studio sound - American Radio History

studio sound - American Radio History
studio sound
March 1977 45p
AND BROADCAST ENGINEERING
AMPLIFIERS
reo
IFN
Cadac Automated Recording /Remix Equipment
*Care® is a system of digital data storage which
can store, retrieve and update the settings of
analogue and switching functions of a mixing
console.
Pye Records chose a Cadac Care equipped
console for their new London studios.
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Cadac, first in European audio technology.
Cadac (London) Ltd.
141, Lower Luton Road, Harpenden, Herts AL5 5EL
Harpenden (STD 05827) 64351 Telex 826323
Cadac (Holland) B.V.
G.V. Amstelstraat 97, Hilversum, Holland
0215017722 Telex 43834
EDITOR RAY CARTER
TECHNICAL EDITOR FRANK OGDEN
EDITORIAL PRODUCTION
DRUSILLA DALRYMPLE
CONSULTANT HUGH FORD
SECRETARY WENDY SMEETH
EXECUTIVE ADVERTISEMENT
MANAGER
DOUGLAS G. SHUARD
ADVERTISEMENT MANAGER
TONY NEWMAN
THE LINK HOUSE GROUP
Editorial and Advertising Offices:
LINK HOUSE, DINGWALL AVENUE,
CROYDON CR9 2TA, ENGLAND
Telephone: 01 -686 2599
Telex:
947709
Telegrams: Aviculture Croydon
7 Link House Holdings Ltd 1976
11 rights reserved.
STUDIO SOUND is published on the 14th of the
preceding month unless that date falls on a Sunday
when it appears on the Saturday.
SUBSCRIPT IONS
All enquiries to: Subscription Dept, Link House, 25
West Street, Poole, Dorset 8H15 ILL. Poole (02013)
71171.
DISTRIBUTION
STUDIO SOUND, published monthly, enables engineers and studio management to keep abreast of new
technical and commercial developments in electronic
communication. It is available without charge to
qualified readers; these are directors managers,
executives and key personnel actively engaged in the
sound recording, broadcasting and cinematograph
industries in any part of the world. Non -qualifying
readers can buy STUDIO SOUND at an annual
subscription of£7.60(UK) or £7.20 (Overseas). Express
(air mail) as follows (extra charge over paid or free
subscription): Argentina (B), Angola (B), Australia
C), Austria (X), Barbados (B), Belgium (X), Bermuda
B), Botswana (B), Brazil (B), Bulgaria (X), Canada
:), Chile (B), Colombia (B), Cyprus (X), Denmark
X), Finland (X), France (X), Ghana (B), Greece (X),
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1, New Zealand (C), Nigeria (B), Norway (X), Peru
=), Philippines (C), Poland (X), Portugal (X),
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(B), USA (B), Virgin Islands (B), West Germany (X),
Yugoslavia (X), Zambia (B).
studio sound
AND BROADCAST ENGINEERING
Pure coincidence
?
With mic technique, it's not always wise to come off the fence and become a strict
adherent to
either close miking or crossed pair. Such polarisation usually indicates partial loss of
sight of
the final objective, a pleasing interpretation of a musical scenario. Further, it tends
to show a
lack of experience in practical recording.
For instance, no intensity of commitment could justify the Blumlein approach in the vicinity
of a motorway or the flight path into an airport whereas, perhaps, the atmospherics and
ambience of a Marlboro Medium Tar cough might be permitted. Conversely, some things
are
just too big for close miking even though a lot of recording channels may be used. In this case,
many crossed pairs can create a series of stereo images of the individual instrument
sections
which together make up a larger crossed pair picture.
Practical recording technique has always been an empirical science usually defying established
doctrines; the best known engineers have never been doctrinaire. They make decisions on
experience rather than esoterics. After all, strict phase relationships may be important but can
be discounted provided it sounds ok when the mono button is pressed, assuming the
mix was
right for stereo in the first place
open mind instead of closed technique.
...
APRS & Co. Ltd.
This year, 19 manufacturing members of the Association of Professional Recording Studios
will go to Paris to exhibit their wares at the 56th AES exhibition and, deservedly,
do well as a
result. Nobody would, or should, resent this -for too long British equipment manufacturers
have suffered the constraints of a strongly parochial attitude towards their own craft. Indeed, it
seems a shame that more of the manufacturing membership of the APRS didn't go along with
the others to market an advanced technology par excellence.
What is less understandable concerns the basic dichotomy (or lack of it) between the manufacturing and recording aspects of the APRS. Which particular ethnic group does the organisation
provide for? Without doubt, certain members among its ranks deserve nothing but credit for
propagating degrees of intelligence within the recording industry. For instance, John Borwick's
engineer refresher course at Surrey University, accepting the limitations of five days, earns
nothing but praise for its aims. Communication is education and should constitute a fundamental
concept of the Association.
From a functional aspect, the APRS should recognise its role as a communicative body rather
than be mostly pre-occupied with the interests of its manufacturing members; they should be
termed a separate entity and organised accordingly, even within the ranks of the AES which
would seem to be an organisation better suited to their needs.
The APRS should serve the recording industry rather than its peripherals.
contents
FEATURES
THE CADAC APPROACH TO AUTOMATED MIXING
Robin Bransbury
32
AES 56th CONVENTION: A PREVIEW
38
A QUESTION OF COINCIDENCE
Trygg Tryggvason
48
SURVEY: POWER AMPLIFIERS
50
Zones
X
A
B
C
c
Europe goes air mail regardless 2nd class air mail
£18.78 (12 issues)
£18.84 (12 issues)
£22.56 (12 issues)
INDERS
Loose -leaf binders for annual volumes of STUDIO
SOUND are available from Modern Bookbinders,
hadwick Street, Blackburn, Lancashire. Price is
2.00 (UK and overseas)
Please quote the volume
umber or date when ordering.
COLUMNS
NEWS
26
WORK
62
REVIEWS
STUDER A68 STEREO POWER AMPLIFIER
Hugh Ford
68
ALTEC POWER AMPLIFIER 9440A
AB C
YIYII.
OF
WIMOO.
TMl OOIT
MN4TpNl
otal average net circulation of 8899 per issue during
975. UK. 5689 overseas: 3210. Total average net
irculation of 10030 for January 1976. UK: 6003,
- erseas: 4027
Hugh Ford
DUNLAP CLARKE DREADNAUGHT
74
1000
POWER AMPLIFIER
Hugh Ford
80
MARCH
1977
VOLUME
19
NUMBER
3
Roger Squiie!i
the specialists in equipment for radio studios
PROFESSIONAL EQUIPMENT AT COMPETITIVE PRICES FOR BOTH
BROADCASTING STUDIOS -AND RADIO RECORDING STUDIOS
ALL PRICES ARE NETT PROFESSIONAL
BROADCAST TURNTABLES
CARTRIDGE MACHINES
/MIL
sqvlHe
^
INSTANT
START
MEE
SQUIRE S3000 Mk.
R/Playback compat.
II
íI75
TAPECASTER
X700
full range, from
£470
BRAND NEW PRODUCTION
MIXER FROM ALLEN & HEATH.
STEREO D.J. SELF -OP, 6CH,
RUSSCO from £202
!
MANY FEATURES
S
MOM
f
-
.
IIIND
4
4 a
Ai
.
v
v
o
Chilton Mixers
PRICES FROM £410
ALLEN
FEATURING
4 4
T
!
-
Allen and Heath MINIMIXERS
6 into 2
ONLY E148
£350
&
HEATH
POP MIXERS
Remote starts
Voice auto fade
Full studio spec.
16/2
14/2
12/2
10/2
...
... £645
...
...
...
f587
£529
£471
Squire S4000 6ch M/S Mixer £251
cartridge machines at special prices. Alice STM 6 portable 6 channel stereo transmission mixer ... £46500
...
... £16.60
Stanton 500 AL Cartridges
Budget -priced mit /gram mixers, from ... E6500
... £58.00
AKG Studio Mics, from ...
...
Uher Interview Recorders
... E242.00
...
Anglepoise Mic Stands
...
... £1475
...
... £134.00
HH variable echo units
Ex -demo Spotmaster Model 1000
ALSO
UK CUSTOMERS VAT EXTRA
DELIVERY ANYWHERE IN
UK PLUS EXPORT SERVICE
Most items available ex- stock. Prices subject to change without notice.
Imported goods subject to changes in exchange rates.
SHOWROOMS OPEN TUESDAY
OPENING TIMES 10.00 a.m. -5.00 p.m.
Talk to our Manager Tony Kingsley.
He knows about Radio Studios.
SOME ITEMS ALSO AVAILABLE FROM
OUR MANCHESTER BRANCH.
4
STUDIO SOUND, MARCH
1977
- SATURDAY.
Roger Squiis!a
CLOSED
MONDAYS
LATE NIGHT WEDNESDAYS UNTIL 8.00 p.m.
STUDIO EQUIPMENT DIVISION
55 CHARLBERT STREET, LONDON NW8 6JN
Telephone 01 -722 81
I
I
complete the
picture...
...with their new NAGRA E
A dilemma Nagra were
suffering for some time, was how to produce a self
contained Professional Tape Recorder which incorporated all the qualities of
their highly acclaimed Nagra 4.2, but could be marketed in the lower price
range. Almost anyone can manufacture a cheaper version of a successful
product but Nagra were determined not to sacrifice standards for economy.
Well, we are happy to announce they have achieved the perfect solution with
used on the Nagra 4 Series. which has become renowned worldwide for its
reliability and performance.
Good news, for the operator in the field, is that the new model is slimmer and
lighter than the 4.2 and comes complete with a measuring probe. circuit diagram and some essential spares. This means that bias adjustment resulting
from tape type change can be easily carried out away from base. A single
microphone input is provided which can be switched to accept dynamic or
condenser types.
-
the new Nagra E.
The astounding saving of around 50% has been principally achieved by the
simplification of the speed stabiliser
single operating speed of 71/2 ips is
provided. The tape deck and transport mechanism are closely similar to that
-a
TECHNICAL DATA
Dimensions: 13.8 x 9.3 x 4in (351 x 336 x 104 mm)
Weight: 12.6 lbs (5.75 kg) with tape and batteries
Wow and flutter: + 0.1%
1
Reels:
7 in cover open, 5 in cover closed.
Loudspeaker:1.0W
Headphones output both switchable Tape /Direct
Frequency response recorded at -20 dB: 30- 15.000 Hz f_
SIN ratio, ASA'A ": better than 66dB
Temperature range: 4
158 °F( -30 to + 70'C)
°-
2
dB
Please send me further details of the new NAGRA
in the range.
E
and other models
1
Name
1
1
Address
1
1
'
1
1
HAYDEN
I
HAYDEN LABORATORIES LTD
Hayden House, Churchtield Road, Chalfont St. Peter,
Bucks, SL9 9EW Tel: Gerrards Cross 88447
SS2/NAG
1
AA
5
ROLAND SYSTEM 700 Synthesizer
=IIIIIIIU
111111
IIIa
FEATURES OF THE SYSTEM 700 SYNTHESIZER
SPECIAL POINTS:
The remarkable Roland System 700, not only the ultimate in synthesizers but a system offering an infinite variety of applications!
For use by musicians and composers, for audio research and for
the teaching of acoustics. The unit on display in our showrooms
is probably the only one on public view anywhere in the U.K.
£9,200 in complete form as illustrated, and also available as a
modular unit.
The System 700
optional sections.
Cost
629, High Road, leytonstone,1.11
NEAL'
NEAL
NEAL
STEREO
3 CHANNEL AUDIO VISUAL
4 CHANNEL RECORDERS
I
4
40Series
Channel
MONO AV DOLBY
GRPHRS
Having quietly reached the top in the domestic hi fi
market, we have taken the logical step towards semipro and pro equipment. With great interest we are
investigating equipment to fill a new showroom for
musicians and the more budget conscious studios.
We have found much to recommend from Keith
Monks, Beyer, Teac, Revox, Calrec, PWB, DBX and
the redoubtable Naim NAP250 power amp.
Special models
to order
110
-fast
01.539.0228
Starting with the Teac Creative Centre we are working on DBX, Dolby, various mixers, 2 and 4 channel
recorders, mics, stands, monitors, amps and accessories,
to see how they fare under live conditions. From this
build up of information and experience we will be
able more easily to advise what is, and isn't, going to
work well for you.
CASSETTE
RECORDERS
FOR THE
PROFESSIONAL
USER
NEAL Range includes.
STEREO DOLBY
102,103
modular console type synthesizer with five
There are 47 highly dependable and durable
modules to choose from for making any desired arrangement.
and
outputs
of the modules are compatible with all
The inputs
professional audio equipment, so they are easy to use in any
In the main console the modules are logically
arrangement.
arranged according to the signal paths. The System 700 has DIN
jack connections for two separate 61 key keyboard controllers and
provisions for control by external musical instruments.
tú FREEDMANS
of the basic unit starts at around £2,700.
is a
MULL
102AV, 103AV STEREO AV DOLBY
4CHANNEL
140 SERIES
HEAVY DUTY REPLAY
104
Come in and listen
GRAHAMS
TRANSCRIPTION CASSETTE RECORDERS
NORTH EAST AUDIO LIMITED
5
6
Charlotte Square, Newcastle upon Tyne
NE
STUDIO SOUND, MARCH
1
4XE Telephone 10632126660
1977
88
PENTONVILLE
Telephone
01
-837 4412
ROAD,
LONDON
NI
fl hit in the ma/thig.. clearly
fl Tirerltconsole...naturalll,
.
'A' and 'B' Series studio consoles and the Fleximix portable mixer are developed
from the first -hand experience of our own engineers working in the recording environment.
This, together with the painstaking assessment of user requirements, has resulted in superlative
equipment which frees the recording engineer to exercise his creative talents to the fLlll.
Trident sound desks are used by discerning people the World over.
The Trident
Trident Audio Developments Ltd.
Sales
36-44
United States Agents:
East Coast:
Office:
Audiotechniques Inc.,
142 Hamilton Avenue, Stamfordl, Conn.
Brewer Street London WI.
Tel: 01 -439 4177
Telex: Tridisc 27782
06902.
Tel: (203) 359 2312
Contact: Adam Howell.
West Coast:
Factory Address:
Studio Maintenance Service,
2444 Wilshire Blvd., Suite 214, Santa Monica,
Shepperton Studios
Squiresbridge Road
Shepperton Middlesex.
Ca. 90403.
Tel: (213) 990 5855
Contact: David Michaels.
Tel: (09328) 60241 Chertsey
TRIAD
7
a
question of ECONOMICS
?
We manufacture what is generally called portable mixing
desks although for many applications are permanent fixtures.
The facilities supplied and performance achieved are in no
way indicated by the basic price. We offer these basic units
not to give on first sight a price advantage over our competitors, but as a genuine attempt to streamline production with
its ECONOMIC and time -saving advantages.
A purchaser either on a tight budget or with limited experience
can custom -build over a period without (in most cases *) a
factory return.
The confidence in and ECONOMICS of our products are
expressed by the fact that over 75% are exported.
seen from the
professional
angle
The front fader box is extended by 10cm if HF and LF Filters
and/or addition Auxs are fitted.
Basic Unit contains: Per channel, Line input and
Gain, HF and LF Eq, Two Aux Sends, one with
pre /post, PFL, Pan, Channel routing, Ch fader.
OUTPUT GROUP: PPM with line /monitor Sw,
Oscillator, Switchable 40 Hz, 100 Hz, kHz, 10 kHz,
15 kHz, 2 Line/2 Monitor /2 Phones. Outputs +19
dBm, Mono /Stereo Sw, Aux Return (echo),
Tape /Line /PFL Sw, select on Monitor or Phones
output (Monitor mix 12/4 only). Optional Extras:
Balanced Mic, Gram, Presence, Talkback, Limiter/
Compressor, HF and LF Filters, 24v Power Supply.
1
the 201 is something
quite personal ...
The M 201 Hypercardioid moving coil
microphone is designed for recording or
broadcasting. The M 201 offers excellent
Separation characteristics in extreme
accoustical conditions.
Specifications:
Frequency Response: 40 -18000 Hz.
Output Level at kHz: 0,14 mV /;j bar
^_ -56 dbm (0 dbm
1 mW/10
dynes /cm2). EIA Sensitivity Rating:
-149 dbm. Hum Pickup Level:
Tesla (50 Hz). Polar Pattern:
5 IL V/5
Hypercardioid. Output Impedance:
200 12. Load Impedance: > 1000 2.
Connections: M 201 N (C) = Cannon
XLR -3 -50 T or Switchcraft: 2 +3 =
200 4., 1 = ground. M 201 N = 3 -pin
DIN plug T 3262: 1 +3 = 200 52
2 = ground. M 201 N (6) = 6 pin
1
P.
.
Tuchel.
Dimensions: length 6 ", shaft
Weight: 8,60 oz.
Basic
£410.00
input
in 4 out
£585.00
M10;'2 Mk4
M16,2 16
M12/4 12
0 0,95 ".
£675.00
All -I-8% VAT UK Sales
MAGNETIC TAPES LTD.
Chilton Works, Garden Rd, Richmond, Surrey
Telephone 01 -876 7957
TW9 4NS
8
STUDIO SOUND, MARCH
1977
BEYER DYNAMIC (GB) LIMITED
Clair Road, Haywards Heath, Sussex.
Tel: Haywards Heath 51003
1
Standing Room Only for
SR
Shure's SR auditorium -size professional sound reinforcement componentry
is probably the only equipment that's been field -proved in Opryland, Las
Vegas and Moscow. The SR's modular flexibility has proved its adaptability
in outdoor rock festivals, theatres, and on the road with many of the world's
popular entertainers. Best of all, the SR's rugged durability and enormous
power potential make it the expandable sound investment of a lifetime. SR
components can be used as a system, or inserted as individual links within
a system of quality componentry in virtually unlimited combinations.
Shure Electronics Limited
Eccleston Road, Maidstone ME15 6AU
Telephone: Maidstone (0622) 59881
ri SHURE
9
Alice BROADCASTING
- THE NEW GENERATION
of direct and audio assignment switching with a considerable amount
of ingenious lock-out' and priority arrangements to prevent
howl- round.
During the Winter of 1976, John Lumsden (Chief Engineer, Radio
Clyde) and Ted Fletcher (Managing Director, Alice) together and
separately worked on accumulated experience over years of broadcasting engineering to produce a self -drive console, simple enough
for the most non -technical disc jockey but versatile enough to master
control election night.
Monitoring systems are equally revolutionary in that any combination of P.F.L., pre-hear (any incoming signal) studio output,
station output etc. etc. may be applied to headphones or loudspeakers
in almost any combination. Thus, an experienced operator could
listen to mono studio output in one ear while at the same time feeding completely different combinations to two other headphone
systems in stereo. (An extreme case, but possible).
The aim was to design, construct and install the systems by 31st
December 1976 -Alice was late. The new thinking throughout the
system could not be telescoped into such a frenetic time scale and,
even with wire men working throughout the Christmas holiday,
completion was not until early January.
light column P.P.Ms monitor desk output left and right with
standard P.P.M. indicating mono output. A fourth P.P.M. allows
monitoring of P.F.L. and other systems.
Plasma
Tuesday Rh January at 4.00 p.m. was the magic moment when the
new console (the first of two) went on the air with no fuss or bother
-but a lot of very tired engineers.
a
I
Time keeping is accomplished by a digital clock with count up and
down facility centrally mounted in the mixer above a substantial
The Alice AM 2G system is almost certainly the most advanced
broadcasting mixer in the world at the time of writing. Not only
does the technical performance set new standards but the facilities
offered put both programming and operation into a new dimension
where all things are possible.
script area.
Control and monitoring of all trans nission systems is achieved with
system of push buttons and status indicators on the central panel,
controlling delay systems, studio to transmitter switching, transmitter status and studio status.
a
The basic system incorporates microphone inputs with individual
peak limiters pre- assigned from various studio positions. Stereo
channels at line level with selectable inputs handle all other signal
sources switched in such a way that any source from anywhere in
the station or on line circuits to the station can be immediately
switched to any stereo channel. This is achieved by a combination
This new generation of broadcasting technology is now a working
reality and we at Alice thank Radio Clyde for giving us the
opportunity to make it so.
(we've always made quiet mixers)
STANCOIL LTD.,
Alexandra Road, WINDSOR 51056
EVENTIDE CLOCK WORKS
IM
ANNOUNCE THE
11,
FEEDBACK
INPUT LEVEL
MOOEL
H
HARMONIZER
1.3
U
ANTI- FEEDBACK
MANUAL
EVENTIDE
r,
CLOCK WORKS
HIC
PITCH PATIO
0,175,,
voo
Si
1111111111111111
10
STUDIO SOUND, MARCH
SPECIAL EFFECTS
DIGITAL DELAY
PITCH CHANGER
The HARMONIZER employs digital circuitry and
Random Access Memories to actually
transpose input signals by up to a full octave up
or down. Unlike the so- called "frequency
shifter" which creates dissonances, the
Harmonizer preserves all harmonic ratios and
thus musical values. Any musical interval can be
achieved by the continuously variable control,
and an optional monophonic or polyphonic
keyboard allows real -time "playing" of the
Harmonizer, so that the musician can
harmonize with himself.
1977
The HARMONIZER is a low -cost, very versatile
digital delay line. The delay is variable in
7.5 ms steps up to 112.5 ms a second output is
optionally available that varies up to 82.5 ms.
;
ANTI -FEEDBACK
POWER
-111111111111
Feedback caused by energy build -up due to
room resonance is decreased by shifting
successive repetitions of the same signal away
from the original frequency.
It can be used to speed up and slow down tapes
without affecting pitch. It can create some of the
wildest effects on record
!
Feldon Audio Ltd Dept SI
126 Great Portland Street
London W1
Tel: 01 -580 4314
Telex: 28668
Speeds 33/4.71/2.15 or 71/2.15.30
Motion sensing + logic.
Vari speed
Edit function
Built in tone generator
End of tape lamp defeat
Capstan motor off
Edit dump
Exclusively from ITA
3
£575 + VAT
1
Over 400 versions available
for immediate delivery.
R diOX fromTA
-7 Harewood Avenue, Maryiebone Road, London NW1 Tel: 01 -486 6162/7833. Telex: 21879.
.
www.americanradiohistory.com
INVITATION
Come and visit ITA snow
UK s biggest for
Showroom
all Studio requirements. All the
following equipment on
demonstration.
-
ALLEN & HEATH
Full range of these
popular mixers available for
demonstration and delivery
NOISE REDUCTION
Both dbx and Dolby
systems in stock..
B
H &H
Echo systems and
high quality at
amplifiers
reasonable cost.
TRIDENT
The superb new Fleximix
system on show for inspection.
ACCESSORIES AND TAPE
Microphones and
headphones from AKG and
Revox. Scotch and Agfa tape at
lowest prices.
NOTE NEW ADDRESS
- ... Mil. MN*
Please send details
EL
ALLEN &HEATH
NOISE REDUCTION
H &H
TRIDENT
ACCESSORIES AND TAPE
Name
Address
-7 Harewood Avenue,
Marylebone Road, London NW1.
Tel: 01 -485 6162/7833.
1
1
Telex: 21879.
www.americanradiohistory.com
ITA - London's
Multitrack Centre
At ITA you can find London's
biggest range of tape recorders,
mixers and ancillary equipment.
Backed by fully professional
service by our own technicians.
TEAC
Four 4- channel machines
from £405
TEAC TASCAM
New range of mixers
including the mini 6 -input Model
2 and two 4- output mixers,
Models 3 and 5
ITAM
4 and 8 output mixers
£690 -E1260
ALICE
AD62 well established
stereo mixer £249
OTARI
Wide range of
professional equipment
including stereo, 4- channel and
8- channel recorders. And the
world's finest in- cassette
duplicator.
TAPE
Lowest prices on Scotch
207 and Agfa PEM368
IMMEDIATE DELIVERY
FINANCE AVAILABLE
Prices exclude VAT
TA
-7 Harewood Avenue,
Marylebone Road, London NW1.
Tel: 01 -485 6162/7833.
Telex: 21879.
1
I
I
Please send details
TEAC
TEAC TASCAM
ITAM
ALICE
OTARI CI
TAPE
Name
Address
..
TRAD
SALES and
SERVICE
NOW
Telephone: Cardington 404
AT OUR
WATFORD SHOWROOMS
Specialists in Service and
Repair of T.R.D. recorders.
All parts, motors, etc.,
available. Collection and
SPECIAL OPENING OFFERS
London
Home Counties.
and
delivery:
A MINI
Neve 24-8 Desk, 4 Compressors,
...
Sends
Echo
8
£9,500
...
Helios 20 -16 -16
Spectrasonics 24 -8-24 eight months old ...
Audio Developments 20 -20 with 16 track
£4,500
Techniques 24 -8, nice condition
Sound Techniques System 12, 18 -4 -16
API 24 -8 -16 12 months old...
COMPLETE WITH REMOTE
£ 16,500
...
...
12300.00
E.G. TEAC A- 3340 -S NEW!
£9,750
.
£3,750
Sound
AMEK 12/4 DESK
VERY COMPREHENSIVE FACILITIES
£5,000
6
£ 16,500
...
16 track
£16,000
Ampex 100 24 track, from
£19,250
Ampex MM 1200 24 track
£9,000
...
100 16 track, from
3 MM
£1,100
2 Studer A62's on trolleys with V.U.
£3,800
Leevers -Rich 8 track
£550
Teac 3340 'S', as new
new
and
secondhand.
All A.K.G. mics in stock,
Selection of Beyer mics in stock.
£320
Pair Lockwood Majors with Tannoy Golds
immaculate
J.B.L. 4502 Studio Monitors,
£650
condition, per pair
AKG MICROPHONES
WITH LEADS
£7,500
3M M56
6
TRACK STUDIO
COMPLETE FOR
FOR SALE
monitor desk
4
1
I
6
MICROPHONE STANDS
1
I
Brand
new
Microphone
with Mic. Clip,
each
Boom
...
Stands
LIS
Dolby A301 units, each ...
2 Dolby M 16 units, each ...
Urie Graphic Equaliser 27 frequency
...
Klark Teknik Graphic Dual II
440
...
Delay
E.M.T. Digital
£3,500
£320
£340
£ 1,000
£2,600
EMT 240 Gold Foil Echo Plate
-
2
303
TANNOY LANCASTER
SPEAKERS (Reconditioned)
2 PAIRS
H/ PHONES
£300
2
WANTED
QUAD
£325
Pair Spendor BC3's
I
REVOX STEREO HS77
ALL STUDIO EQUIPMENT
Desperate for A80 16- track.
Come and see us
and try it out
NOW!
SHOWROOM NOW OPEN AT
DOG HOUSE,
BEDFORD ROAD, COPLE,
BEDFORDSHIRE MK44 3TR
Telephone: CARDINGTON
14
STUDIO SOUND, MARCH
1977
404
149B ST. ALBANS ROAD
WATFORD, HERTS.
Telephone: WATFORD 47988
The 805
in use
Worldwide:
UK
Turkey
USA
S. Africa
Philippines
Switzerland
Denmark
Greece
Sweden
Holland
Belgium
Germany
France
Australia
Finland
ita
1
-7
Itam delivers....
The Itam 805 8 channel recorder gets
you into the Big league FAST. It
provides a new area of penetration
for budget studios.
Facilities like track
bouncing, variable
speed and silent
"drop ins" appeal to
every studio AND
THE CLIENTS
WHO BOOK
YOUR STUDIO
TIME. Get the facts
from our sales desk
who will fill you in on
the details and set
up a finance deal
with your trade -in Portable £790 VAT
Console £1930 VAT
right now.
....the rest only
promise
rn7
Harewood Avenue, Marylebone Road, London NW1. Tel:
Immediate Delivery
01
-485 6162/7833.
Telex:
21879.
STUDIO
EQUIPMENT
SERVICES
r
V-IE FfiCLY
Provide technical services for studio sound equipment
in broadcast and recording applications. We have a
wide range of test equipment which includes 2", ", Z"
and ," test tapes for normal maintenance and line ups.
I
We also plan, supply, build and install equipment.
01 -200 1229
To let you hear the difference
between top flight recorders. To
demonstrate the difference between
microphones, mixers, and speakers.
To reproduce sound in an
environment similar to that which
you are likely to be using. This is
THE FACI LITY. A working model
recording studio and showroom to
let you experience the best
equipment in an 'in -use' situation
without paying 'over- the -moon'
prices.
This is THE FACILITY, which
can accommodate solo artists,
a medium size choir, a pop group.
Can produce radio commercials,
sound tracks, P.A. system tapes.
It's THE FACILITY and it's at
RADFORD HI -FI. The innovators
in Sound.
Al
0
visunL
CHARL_ESFIEL_D
41 Newbold Rd Rugby. CV21 2ND.
Tel
;
(0788)75908
WX Monitors ...
AMCRON VFX 2 Filter /X 'over
AMCRON DI50A
TEAC 3340S. Pro. Spec
NEUMANN U47 fet. ...
NEUMANN KM86
2 JBL 431
I
i
250 00
235 00
320 00
585 00
212 00
222 00
All the above new and unused.
OTARI MX7000 2T with 4T replay 1400 00
OTARI MX7000 4T
...
... 1600 00
Both the above little used console versions.
I 19" Rack cabinet.
42" high, 15"
45.00
2
AMPEX VR5103 Video recorders,
plus 50 tapes (1") and Decca 26"
monitor ...
...
...
...
46500
We buy, sell, repair, hire and install all types
of professional recording and sound reinforce-
Talk to Roger Wall at
ment equipments.
THE FACILITY, RADFORD HI -FI LTD.,
52 -54 GLOUCESTER ROAD,
BRISTOL BS7 8BH.
Telephone: (0272) 422709 Telex: 449315
Griffiths Hansen
EQUIPMENT ON DEMO INCLUDES
ALLEN & HEATH
A.K.G.
BEYER
REVOX
FER ROGRAPH
KLAR K TECHNI
AG FA
SENNHIESER
TEAC
NAKAMICHI
L
16
K
B.G.W.
QUAD
TASCAM
RADFORD AUDIO
BRENELL
TANNOY
J.B.L.
T.D.K.
(Recordings) Ltd
Recording studio specialising in speech and drama for
education, advertising, industrial training, sales and
promotion work.
Open reel and cassette duplicating.
SPENDOR
CHARTWELL
MONITOR AUDIO
STUDIO SOUND, MARCH
1977
J
Public address installation and hire for conferences and
exhibitions etc.
12 BALDERTON STREET,
(Opposite Selfridges)
LONDON WIY ITF
01
-499 1231
GAUSS SLAVES NEVER
STOP WORKING
All over the world they are to be found working away ... in the USA, Argentina,
England, Scotland, Netherlands, Italy, Malasia, France, Australia, Canada, Sweden,
Germany, Norway, Japan, Mexico, Greece, Switzerland, Spain, Portugal, Belgium,
Hungary, Indonesia, South Africa, Egypt, Singapore, New Zealand ... in every major
duplicating company Gauss slave recorders keep up the world's highest production
rate, all the while raising the standard of quality tape duplication and retaining that
extraordinary sound that has kept Gauss the leaders in tape duplication worldwide.
-
1200 System comprises a Master Reproducer model 1210 (1",
versions available) in conjunction with Gauss' exclusive horizontal
pneumatically driven Loop Bin. Up to 20 slaves can be controlled, each
using the Gauss unique Ferrite record head (10 MHz bias).
The Series
l' and
* With duplicating ratio of 32:1.
* The ultimate in gentle handling of master tapes.
* The World Standard in pre - recorded music duplication quality for
cassette and cartridge programmes.
Cetec
ãüdiö.
a
Division of Cetec Systems Ltd.
EUROPEAN OFFICE
SAPPHIRE HOUSE, 16 UXBRIDGE ROAD, EALING, LONDON
MAIN OFFICE
CETEC
W5
2BP.
Telephone: 01 -579
9145 Telex: 935847
AUDIO a Division of Cetec Corporation, 13035 SATICOY ST., P.O. BOX 3941, NORTH HOLLYWOOD, CALIFORNIA 91605, USA. Tel: (213) 875-1900, T.W.X. (910) 499-2669.
'MAC
Tascam 80 -8 and
Models 2, 3, 5 Mixers.
TLC
ti
TEAC 3340S and 2340SX.
The best 4- channel recorders
available, ideal for demos
and multitracking.
The excellent
Brenell range including
the Mini 8 1" machine.
11110
0 ,0
e1111.1111e
00
REVOX A77 mk. 4. Available
standard, high speed,
varispeed, selsync.
v
o
=
Complete range of Allen & Heath
mixers including the famous
Minimixers, Quasi's and Popmixers.
ó
We stock all Nakamichi professional
cassette recorders.
76
Lyndhurst Gardens, Finchley N3
Telephone
Complete range of Tannoy speakers ex- stock.
01 -346
. .........I _.......,...
-
Leading Equipment suppliers to professional and home recording studios.
18
STUDIO SOUND, MARCH
1977
4469
Export service available.
Sweep equaliser,
compressor,
expander, limiter,
all in one unit:
The ADR Vocal Stresser
Its a unique audio package.
And here's where to use it.
in the Broadcast Studio
Make wide adjustments to programme material before broadcast;
eg. 'doctor' telephone lines to make
them more suitable for broadcast.
The equaliser improves signal
quality; the compressor improves
mean level; the expander in gating
mode attenuates noise during
pauses, and the limiter controls
peaks.
In
the Mastering Suite
Control every medium, from disc
cutting to cassette duplication, particularly reducing sibilance and
adjusting overall dynamic balance.
In the Recording Studio
The sky's the limit, or at east the
creative ablity of the artist and the
engineer is. With vocals, or indeed
any signal source, you can get very
exciting sounds.
The Vocal Stresser is basically the
F760X Compex -Limiter and the
E900 Sweep Equaliser integrated
as one, with all functions switch selectable.
For instance, the equaliser can
be switched out of the system and
used as a separate unit, accessible
through is own inputoutput from a
different channel.
Or switched before or after the
Compex -Limiter or even In its side
chain.
The benefits of these three modes
are considerable.
Used before, you get maximum
signal conditioning and still maintain
-
critical overload control.
Used after, you get an enhanced
compression effect although the
limiter gets equally affected by the
varying signal shape.
And intheside chain, the equaliser
becomes an extension of both the
threshold and compressor controls,
making them particularly sensitve to
chosen frequency bands.
Send for full technical specifica
tions.
audio & design recording lid.
St. Michaels, Shinfield Road,
Reading, Berks, UK.
Telephone: Reading (0734) 84487.
Telex: 847605.
Manufacturing members APRS.
REPRESENTED IN; USA- CANADA AUSTRALIA -NEW ZEALAND -JAPAN -SOUTH AFRICA -BRAZILEASTERN EUROPE- BELGIUM- DENMARK- FINLAND-FRANCE -WEST GERMANY-GREECE -HOLLAND ITALY -NORWAY-SWEDEN
-
-SWITZERLAND.
sound
sound better.
We make
Five monitors. One sound. Five JBL studio monitors.
You could record with any one, play back on any other,
and take your pick among the rest for mixing or mastering.
The only differences are acoustic output, size and cost,
No matter wnat size your studio is, you can cross reference with any other studio using JBL's.
But reading isn't knowing for sure. Come listen to
one. Or two. Or five.
C.E.HAMMONDEtCO LTD 105109 Oyster Lane Byfleet Surrey KT147LA
Telephone Byfleet 41131
20
STUDIO SOUND, MARCH
1977
JBL
MIL63
T
111
1111Elaini
WM4
*
The ARA1 Test Set quickly gives yoi
accurate traces f audio system frecuency
responses. In just a few seconds, th s
self-contained instrument clealy displays
response as a gain/frequency olot cn a
long-persistence CRT. Outputs are
provided for operating an V( clottex
Whether yoi use the internal sweep oscillato-,
or an exterral signal, the ARAI
requires no synchronisation and adjists.,
automatical y to the incoming frequency. I:
covers 20Hz to 200kHz. with resolution down
to 0.1dB over a very wide dynamic range.
Switched attenuators for output
level and input sensitivity ensure
fast and p-ecise evaluation of all audio devices,
whether laving nominally flat response or a
steep-cut characteristic. You can adjust the
sweep rate, set upper and lower limits
independently, and use one-shot or repetitive
sweeps triggered electrically or manually.
I
-----
The Fer-ograph Professional ARAI.
Fast. AccLrate. And easy to use.
Send for Lill information today.
FERROGRAPH PROFESSIONAL ARAL
Wilmot Breeden Electronics
Ferrograph
Please send me information about the
Name
Position
Company
Address
Rendar
Wayne Kerr
rrograph Professional ARA1.
Telephone
Wilmot Breeden Electronics Limited, 442 Bath Road, Slough, SL1 6BB, England.
Telephone: Burnham (06286) 62511 Telex: 847297
SS
3
77
21
BßOADCA$TIIYIi
PERFECTION
Hampstead High Fidelity-professional equipment
for professional people, and distributors for the
complete range of CE (formerly STC) microphones;
a range of microphones covering the whole
spectrum of inside and outside broadcast uses.
ALL IN STOCK AT OUR LONDON SHOWROOM
We also supply the Keith Monks range of
microphone stands, booms and accessories.
ALL IN STOCK AT OUR LONDON SHOWROOM
Choose from our range of professional equipment.
REVOX, YAMAHA, NAKAMICHI, HARMON KARDON,
GALE, DAHLQUIST AND SENNHEISER
For the home market we carry in stock at our London
Showrooms a comprehensive range of superb professional
equipment.
EXPORT IS OUR SPECIALITY.
24 HOUR SERVICE WORLD WIDE.
Hampstead High Fidelity
Ltd
Hampstead High Street
London NW31QH, England
Tel: 01 -435 0999/6377
63
All microphones shown are used by the major TV and radio
networks worldwide.
An introduction from TWEED
the
P104
Portable
-designed as a true
portable, without compromise
-the
same modular
high quality,
top performance
plus extra facilities
an even
For o
Specialists in Audio Control
Equipment for the Sound Recording
and Broadcast Industries
22
STUDIO SOUND, MARCH '977
in
smaller package.
full specification leaflet write or 'phone:
TWEED
audio
ELECTRONICS
ROSEWOOD INDUSTRIAL ESTATE, KELSO, ROXDURGHSHIRE
STD 057 32
TELEPHONE 2983
SCOTLAND
et t
e New deader....
\;.,,.;,
\\\\\\
\\.,
S.500D Specification Features
*
*
Power output 340W R.M.S. into 4 ohms
500W R.M.S. into 2.5 ohms
Bridged Mono output 900W R.M.S. into 5 ohms
640W R.M.S. into 8 ohms
* Intermodulation Distortion
20Hz to 20KHz
F1
Less than 0.02% from
60Hz.
* Integral "Force Cooled Dissipators" for reliable
operation into adverse loads.
Power Bandwidth +0, -1dB from D.C. to 20KHz.
Very low Transient Intermodulation Distortion.
Restricted rise time, fast slew rate.
Input sensitivity 0.75V for 300W into 4 ohms.
* Noise 105dB Below 180W into 8 ohms 10Hz to
20KHz. Unweighted.
* Elaborate system protection against short and
open circuit operation
* Small size 3½" x 19" Rack mounting.
* KVA Toroidal power supply providing 55 joules
of energy.
*
*
1
The 5500-D
A higher standard of power
amplifier design
From the most experienced, well equipped specialist manufacturer
of 'Professional Power Amplifiers' in the U.K.
HIIH
electronic
VIKING WAY, BAR HILL
CAMBRIDGE CB3 8EL
TEL: CRAFTS HILL (0954) 81140
TELEX: 817515 HH ELEC G
PROFESSIONAL
AUDIO
ELECTRONICS
the revolutionary
audio recorder!
When something new arrives in the
recording industry you can bet it's
from Ampex like the revolutionary
-
ATR-100 audio recorder we're just
introducing.
It has a mass of exciting features
that will give you top class recordings
and remarkably good performance. In
AMPEX
24
STUDIO SOUND, MARCH
1977
its transient response, headroom and
improved tape handling, the ATR -100
is starting a quiet revolution in professional recording.
Call your Ampex audio sales engineer at the number below; he's got
some very interesting literature
to send ,you.
Ampex Great Britain Limited,
Acre Road, Reading, Berkshire,
Tel: 85200 Telex: 848345
Geoff Emerick
Didyou ever think you'd have
this many hands?
s
,
14- 144
Well, you will with NECAM. As Chief Engineer of Air
Studios, you and your colleagues are the first in the world to
use a computer assisted mixing system that will give more
hands than you ever imagined and a memory that would be
the envy of Beethoven, Bach, Gershwin and McCartney
rolled into one.
No, NECAM won't do your job for you. But it is
the best tool around to help you eliminate the dull and
repetitive tasks that are part of the every day life of the
mixdown engineer. It will enable you to concentrate on
what you are really there for, the final artistic results.
14.-
N ECAM will let you be creative because it provides
the simplest possible interface between you and your
equipment. It breaks real time and memory barriers, offers a
unique merge function, is incredibly adaptable and versatile.
And at all times has a control system that keeps you informed
of what is going on.
Geoff, Neve spent years talking to people like you
before it developed N ECAM. It had to, to give you the
market's most effective system for the management of the
mixdown process.
So enjoy yourself and NECAM and let the world
hear from you both.
Neve
N
The Sound of Neve is Worldwide
Rupert Neve Et Co., Ltd., Cambridge House, Melbourn, Royston, Herts.
SG8 6AU, England. Tel Royston (0763) 60776 Telex 81381. Cables NEVE Cambridge.
Rupert Neve Incorporated, Hollywood. Rupert Neve of Canada Ltd. Rupert Neve Gm6H.
25
Amcron equaliser
This company now manufactures a
stereo equaliser for professional
use'. The EQ2 features 11 bands
of parametric eq spread from 20 to
20k Hz with up to +15 dB of control. It also incorporates an
unusual, if not unknown, facility.
Each band has a control allowing
4- octave variation of centre frequency.
Balanced inputs offer either unity
of -i -10 dB gain; leds are provided
to monitor and indicate overload.
Claimed frequency response is
within 0.1 dB from 20 to 20k Hz
with im distortion of below 0.01
at rated output of 2.5V.
Ltd,
Laboratories
Macinnes
Macinnes House, Carlton Park
Industrial Estate, Saxmundham,
Suffolk IP17 2NL.
Phone: 0728-2262/2615.
puts and quadraphonic mix -down.
Sound monitoring is by JBL
speakers and ancillary equipment
includes an auto phase unit.
In the studio area, a balcony has
been built to accommodate ten
musicians, enlarging the total capacity to 30 performers. The mobile
unit has been very active with a
seven day session in Munster,
Germany just completed, where a
live recording of massed bands and
London WI. Phone: 01 -439 4177. choirs was recorded for the GerFactory address: Shepperton man Red Cross.
Studios, Squires Bridge Road,
Shepperton, Middlesex. Phone:
09328 -60241.
US agent (West Coast): Studio
Maintenance Service, 2444 Wilshire Matrix H
the best so far?
Blvd, Suite 21 I, Santa Monica, Ca It's nice to know that the British
90403, USA. Phone: (213) 990 Broadcasting Corporation spends
5855.
our licence money on things other
than turgid soap box drama such as
The Brothers and famed BBC tea.
The Corporation's engineering re-
-
Haggis
After eight weeks of non -activity in
the recording scene, Craighall
Studio is now back in operation
after the completion of major
alterations. The control room has
been completely redesigned, and
the floor lowered by three feet to
give a larger cubic capacity. A new
Neve 80.58 Sound Console has been
installed -the first to be commissioned in a UK studio -with
facilities for 24 inputs and 24 out-
search department, after experimenting with matrix A, B, C, etc,
has hit on the H variation which
seems to be aurally the best matrix
system so far devised.
It is almost certainly the most
workable; the strongest feature of
Matrix H concerns the claimed
compatibility with both stereo and
mono. This was convincingly shown
at a recent system demonstration
organised by designer David
Meares using 'H' encoded discrete
Small Studer mixer
Studer has introduced a modular
construction mixer allowing incorporation of up to 12 modules. These
may comprise of either eight inputs
and four masters or 11 inputs and
one master; naturally, any combination in between is feasible.
It occupies the same space as an
A67 tape machine. It contains rechargeable batteries giving five
hours of continuous use. It can
also be conventionally mains
powered, or it may be run from an
external 12V car battery using an
internal dc to dc convertor.
Designated type 169, each input
section features balanced input, hi,
lo and mid eq, pfl and solo switching. Modules also carry reverberation and foldback lines. The stereo
version with twin ppms costs
£3500.
FWO Bauch Ltd, 49 Theobald
Street, Borehamwood, Herts WD6
4RZ.
Phone: 01- 953 0091.
Studer 169
portable mixer
Trident change of address
The January survey of multitrack
mixers contained an incorrect
address for Trident Audio Developments Ltd. The entry should have
read:
Sales office: 36/44 Brewer Street,
26
STUDIO SOUND, MARCH 1977
quad material from the tape vaults
of the BBC. He acknowledges that
this isn't perhaps the fairest way
since it precludes the use of existing
quad system material for a/b comparison purposes. However, he did
state that no special recording
techniques were used to produce
the discrete four channel master
tape; mic placement 'optimisation'
would clearly have been impossible
with many of the demo examples
since some had been recorded before the inception of Matrix H.
The men from the BBC stated
that they developed their own
matrix system because all the existing concepts were inadequate for
broadcast use. Carrier systems, such
as CD -4 and UD -4, were ruled out
because of transmission bandwidth
limitations. QS was excluded solely
through lack of mono compatibility; everyone agreed that it was
capable of very good quad performance and excellent stereo compatibility but things tended to
disappear when mixed to mono.
SQ was regarded with little enthusiasm for both quad and mono
performance although it offers
good stereo. Any 4:3:4 system was
discounted because the cost of
small market volume tuners would
be prohibitive since three channel
transmission equipment requires
more than just a simple decoder,
connected to the detector output.
Matrix H represents a hybrid
approach using the BBC's own
encoding phase vectors and a logic
decoding system `mainly based on
a commercial variable matrix decoder' believed to bear more than a
passing resemblance to the Sansui
Variomatrix. If the Corporation
decides to adopt Matrix H for regular quad /stereo transmissions (and
this is nowhere to being decided)
then it will simply publish details
of the matrix characteristic for use
by anyone without payment of
licence fee.
As demonstrated, Matrix H
represents a real broadcasting advance enabling both four channel
ping pong and rather more useful
ambience. Sound images could be
and were located solidly in almost
any position except the side where
they became very diffused, appearing to come from high overhead.
The BBC played an extract from
the Britten opera Paul Bunyon. The
solidity of the aural stage was quite
remarkable, forming a semi -circle
around the listener. If anything,
images were almost too strong; at
one point it seemed that the cast,
walking around, must inevitably
collide with musicians in the
orchestra pit. Still, subtler mic
technique should solve that.
Frank Ogden
28 *-
Price/Performance Leaders
from Orban /Passound
Model 245E Stereo Synthesiser
Uses a unique and patented
process to create realistic and mono compatible
synthesised stereo from a mono source.
Model 516EC Dynamic Sibilance Controller
Three independent channels of easily
adjusted and effective de- essing. Tracking automatically
over a wide range of input signals.
.....
.:
171,
Model 621B Parametric Equaliser
Two channels of overlapping four band
parametric equalisation with continuously variable
tuning, equalisation level and bandwidth.
'Constant Q' rather than reciprocal equalisation curves
for musically useful extremes of EQ.
For full information or a demonstration of any of the Orban
price -performance leaders, contact
:
Scenic Sounds Equipment, 27/31 Bryanston Street, London W1.
Phone 01 -935 0141
In Scandinavia
Ing Firma Jan Setterberg, Kungsgatan
:
5, S411 -19
Gothenberg, Phone 031 1302
16
Orban/Parasound, San Francisco, California 94109
27
NEWS
MFB Studio speaker
Philips, normally known for its
dedication to the consumer market,
has introduced a motional feedback
loudspeaker aimed specifically at
studio monitoring applications.
Using a tri- amplified array, the
545 100W unit produces a claimed
108 dB spl measured at 1 m. The
power amplifier electronics, housed
within the speaker enclosure (70
litres) incorporates a 50W bass
amp /driver utilising the mfb correction principle, a 35W mid range
amp /dome driver and a 15W hf
amp /dome driver combination. All
three amplifiers and their associated drive units feature electronic
cutouts in the event of excessive
power dissipation. Input is balanced
line with both DIN and Cannon
plugs as standard fittings.
The mfb principle used in conjunction with the bass driver is
fairly well known. Philips use a
piezoelectric transducer element
attached to the bass cone centre
which continually monitors acceleration of the cone assembly.
The output from this is differentiated to yield positional information which is then compared with
the input signal in a simple comparator. The difference signal
produced drives the bass amp/
driver combination.
The manufacturers state that the
main advantage derives from the
reduced distortion produced at
high level, low frequencies. Further,
the system claims to extend the bass
response further down the frequency
range to a point not normally
associated with the actual enclosure
size used.
A brief demonstration of the 54.5
speakers proved fairly convincing
as to system operation. However,
this was a subjective impression
without any kind of reference point,
but even so .. .
They cost about £670 each.
Philips Electrical Ltd, Century
Avenue,
House,
Shaftesbury
London WC2H 8AS. Phone: 01 -437
7777.
Automatt
Situated in San Francisco, it provides both coffee and studio time.
It also claims to be the first studio
in the world to interface an Allison
Memory Plus automation system
with a Harrison 4032 mixing desk.
David Rubinson -once fired by
Capitol Records in 1964 -built the
studio as a logical extension to his
recording and record production
interests; Fred Catero, long time
buddy and constant engineering
companion, will head the engineering staff. As such, the operating
company is called David Rubinson
& Friends Inc.
They describe their studio as `not
gigantic'; rather, they refer to it as
'small and intimate allowing complete interchange between and
among the various people involved
in recording'. One of the most interesting features is musician foldback
system. Designed by Eric Porter-
q\' id
Hnd5
LNG-
Fred Catero
of Automatt
smiling
28
STUDIO SOUND, MARCH 1977
&.
This Canary 1012 mixer costs only £255
New Canary for £255
Canary Mixing Desks Ltd has
enabling each and every musician introduced a 10/2 portable mixer
in the studio to mix his own cue for use by either small bands for
balance. This means that any and live performance, or in small scale
everyone may make his own mix of recording applications.
It features 10 low impedance
all the relevant inputs potentially
supplied to the foldback cans; he balanced inputs, three band eq on
doesn't need to rely on a compro- all channels, foldback and echo
mise balance selected by the session send /channel, pfl, panning, master
vu meters and master eq. There is a
engineer. Very unusual.
The studio address is: The headphone monitoring facility. The
Automatt, 827 Folsom Street, San unit is housed in a flight case complete with power supply and costs
Francisco, Ca 94107, USA.
£255.
Phone: (415) 777 9230.
Cannons will set you back a
further £25.
Canary Mixing Desks Ltd, 17
West Hill, Wandsworth, London
RCA custom consoles
A new booklet is available which SW 18 1RB. Phone: 01- 870 7722.
provides detailed information on
the RCA BC -50 custom audio Response plot
modular self build mixing system. The UREI response plotter is now
It includes instructions intended to available in the UK from FWO
help potential users self design Bauch Ltd. The model 200 is reladesks to individual specifications tively low cost and is said to provide
within the standard ordering frame- high resolution plots from a variety
work. It describes each of the of audio equipment at high speed.
It consists of a basic mainframe
modules and the submodules that
are combined to form either a mono housing a Hewlett-Packard high
or stereo broadcast mixing system. resolution 51 cm /s chart recorder.
The booklet, RCA catalogue A plug -in electronics module pronumber 3J5924 -i, is available from vides swept frequency and signal
RCA Broadcast systems, Audio/ reception facilities covering the
Radio Equipment, Building 2/5, range 20 to 20k Hz. Sweep time
is adjustable from 15s to 20 minutes
Camden, NJ 08102, USA.
using a vernier control, or preset
times of 15, 30, 60, and 120s. In
addition to sweep, frequencies may
be manually selected or calibrated
NAB 77
The annual convention of the against spot tones.
National Association of BroadcastThe unit claims an important
ers will take place at the Shoreham design feature in that automatic
Americana Hotel and Sheraton rate sensing slows down the sweep
Park Hotel, Washington DC from rate when amplitude excursions beMarch 27 to 30, 1977. Reports come very involved; this has the
suggest that there will be about 200 effect of increasing the resolution
exhibitors at the accompanying of the instrument where it matters.
exhibition.
Further, it optimises the time taken
In the States, the contact phone for a complete sweep.
number is (202) 293 3500. In the
Specifications include a 0.05 dB
UK, the US trade enquiry service resolution from 20 to 20k Hz with
should be able to help. Phone: a claimed 64 dB dynamic range.
field of CBS, it uses a special four
track headphone cue arrangement
.
01 -499 9000.
.
30
At the BBC,ThomesTelevision,Copitol Rodio,Gronodo,
AirStudiO,ROckfield,Decco,EMI & Strowberry...
they hove...
PERFECTION
AT THEIR FINGERTIPS
Illustrated is our DN27 Third Octave 27 -band
Graphic Equaliser. Also shown is our
DN22, dual -channel, 11 -band unit. Both
have many technical plusses which our
literature describes.
WORLD WIDE DISTRIBUTORS
Klarion Enterprises, So J :h Melbourne, AUSTRALIA
ARC. Sprl., Brussels, BELGIUM
Camtek, Dorval, Quebec, CANADA
Team Sound APS, Charlottenlvnd, DENMARK
Studio -Center, R.E.D. Paris. FRANCE
Audio- Ouipment, Aachen, WEST GERMANY
Pieter Bollen, Eindhoven, HOLLAND
Siv, Ing. Benum & Co., Oslo, NORWAY
Colosseum Acoustics, Johannesburg, SOUTH AFRICA
SATT Elektronik AB, Stockholm, SWEDEN
Ultralinear International, Sinuapora, SINGAPORE
Hammond Industries Syosset N.Y. U.S.A.
Laboacu<ticaSRL, Rome, ITALY
Dr. W. A. Günther ING. SIA. Zürich, SWITZERLAND
,
It's not surprising to find our equipment with
these and many other users: after all, we are
technically superior - as both operator and
engineer can testify, and you may be surprised
to learn that we are no more expensive
This perfection can be yours. Give us a ring
KLA RK
RESEARCH LIMITED
Summerfield Kidderminster
Worcestershire DY117RE
Telephone (0562) 64027
.
NS
5
'
°C.,
29
ember 16; after signing contracts,
the Eastlake crew started work on
Both metric and imperial scaling the 22nd. Work was completed by
can be pushbutton selected with the Eastlake on December 12 with the
chosen scale being shown by leds. finishing touches being put by
Electronics Marquee's Jerry Browse by DeRecording
United
Industries, 11922 Valerio Street, cember 15. The result is a 24 -track
North Hollywood, Ca 91605, USA. room equipped with a small overPhone: (213) 764 1500.
dub facility. The desk is an MCI
UK: FWO Bauch Ltd, 49 Theobald 5-1I with 36 input channels and 32
Herts. outputs.
Borehamwood,
Street,
Phone: 01 -953 0091.
NEWS
Partridge change of address
Partridge Electronics has moved to
a temporary address although the
present telephone number remains
the same:
the new NECAM system manufactured by Neve. This is undoubtedly
a first for the studio already well
known for not being slow with
systems technology.
Naturally such an auspicious
occasion produced a considerable
number of clichèd words from
many people, several of which
came from Air Chairman George
Martin: 'NECAM is the logical
step in our continual aim to be at
the forefront of technological developments in the sound industry and
Fresh Air
Amidst the gentile tinkling of to provide the best recording facilichampagne glasses, AIR studios ties available anywhere
opened their No. 3 equipped with NECAM is another first for AIR.
introduction (see
May 76, pl4) and
tends to overshadow the other
lavish facilities which make up
Studio 3. The basic desk is a 30/24
with servo faders: you could hardly
tell by looking that it wasn't the
Williams, David standard Neve product. This must
.
Marquee remix; L to R. Gery Collins, Tom Hidley, John Eden, Pip
Hawkins and Simon White
.
little
further
STUDIO SOUND,
.
come as an advantage to unaccustomed NECAM users. There are
no less than six tape machines: two
Ferrograph Studio N for special
effects, a 3M 24 -track master and
three Studer A5OR for reduction.
To go with these, there are 36
Dolby channels.
Other equipment includes Tan noy monitors, Crown DC3IIOA
amps, Eventide Harmonizer, Delay
and Flanger, two UA and eight
Neve compressor /limiters, a complete Audio and Design Scamp
system as well as a couple of Klark
Teknik graphic equalisers.
Not bad for one control room.
Partridge Electronics, Homestead,
Canvey Road, Canvey Island,
Essex.
...
a Marquee
Tom Hidley of Eastlake Audio was
Erecting
Before choosing it, we looked at all
the automated systems on the
market and decided that it offered
the most flexibility and efficiency
to the mixdown process.'
Much the same sentiment was
echoed by another, less well known
person who left his glass in the path
of a serve- controlled fader: 'Christ !'
Fortunately, it was empty.
The Neve NECAM system needs
asked by Marquee Studios to finish
off and revamp the new remix suite
in November following rather
harrowing scenes with others inerstwhile
the
during
volved
construction work.
He arrived in England on Nov-
INTRODUCINGA NEW
TAPE DECK FROM A
COMPANYTHAT NEEDS
NO INTRODUCTION.
Besides the standard inch 8 track you
see here, there's a inch 8 track and a 2 inch
16 and a 24 track.
Their features include full solenoid
transport functions. Full sync facilities. Full
modular electronics. Silent drop -ins. Instant
1
1-
start cue. N.A.B. and C.C.I.R. equalisation.
See and hear it at our demo studio.
Pembroke House, Campsbourne Road,
Hornsey, London N8.
Where you can also take the opportunity
to look over the Allen & Heath Mod II mixer.
It's offered with the tape deck in a uniquely
priced package deal.
Or for more information call.Andrew Stirling 340 3291.
30
STUDIO SOUND, MARCH
brn"II
1977
Soundcraft Series 2 Mixers.
Unbeatabl- ve-satility.Immacul_to
specifications.
Six standard consoles:12/4;12/8;16/4;16 /8;
24/4; 24/8.
Dual track sw tch ng, so you can hook up an
8 -group conscle -o a 16 -tra :k recorzer without
repatching. Direct lire outpJts from each input
channel, pre- and ocst -fade.
Four independent auxiliary mixes, pre- or
post -fade.
Options includeVU or Peak Prog-amme
metering, sweep - recuencyequa isa-icn,
Penny & Giles conductive p antic =aders and
special modifications for 16 and 24 track
operation.
THD @ 1K1-z and +4dBm less then 0.02%.
Max mic gain 90dB. relative input noise
128dBm (200a f. IS/1Dx output +22dB-n intc 600
And if you seed studio quality on the road,
we'll sell you an al JminiumflightccE-e as well.
Soundcraft Ele_trcnics Limited
5 -8 Great Sutton street London ECIJOBX
England Telephone 31- 2513631 Telex 21198
Telegrams Sounda-cft LDN EC1
P.O. Box 883 JFK Station Jcmaico
NewYork 11430 USA
Telephone (212) 528 3158 Telex 01 -2203
-
=_
The (adac approach to automated
mixing
ROBIN BRANSBURY'
The design philosophy behind the new system.
*CADAC (LONDON) LTD.
THE concept of automation in sound recording is not new.
As far back as 1939, RCA were working on methods of tying
the audio chain of film soundtrack recorders to the frame count
along the piece of film concerned. Surprisingly, almost all aspects of
modern computer -assisted mixing were used in such early
applications; even voltage controlled amplifiers using variable
valves were incorporated.
During the war years, though, the entertainment industry remained
very largely static; the use of analogue data storage for flight
simulation developed by leaps and bounds and a good many
techniques exploited then find application in present -day technology.
During 1959 -60 Teldec (Telefunken -Decca) conceived the idea
of motorised control elements as a means to automatically adjust
gain, equalisation and disc cutting commands using a system of
optical pick -off from the master tape in an attempt to achieve the
elimination of human error in disc cutting and tape copying.
Polygram introduced a system of recording desk data on the master
tape in 1971 which used a high frequency data stream recorded
between audio tracks. This system was never commercially exploited
outside the company; it is installed and used in Polygram studios
at Paris and Hilversum.
The ill -fated Olive company managed to get a system of desk
automation running before they closed in 1973. The first commercial
exploitation of automated mixing as a package for fitting in mixing
E..
consoles was the Allison system which was relatively successful in
terms of sales. Since the concept was so new to those customers
who installed the system, they were content to overlook the
inevitable drawbacks which were found on the early models and
cheerfully nursed the system along, getting some very
presentable results.
produce magnetic saturation in the coating even if this is spaced
away from the gap by small quantities of dirt, grease or dust, and
even when the area of medium concerned was previously saturated
in the opposite polarity. No erasure of previous information is
needed nor is bias used. Obviously this technique is not applicable
to audio recorders unless the data track is spaced a very long way
away from a used audio track and the record amplifier beefed
up considerably, otherwise crosstalk of data to audio tracks is
inevitable and full medium saturation will not be achieved.
If the amount of information per unit time is severely limited
so that the influence of dropouts is negligible, then the audio machine
can be used with a low -level data signal removing the crosstalk
problem. However this gives a data capacity so low as to be unsuitable
for anything except the logging of simple switch closures and slow
level changes due to the limited number of data characters
stored in unit time.
If all these limitations are true then one may ask how any of
the many audio machine -based systems worked at all. The answer lies
in the phrase 'perfect intelligibility'. If a certain error rate is
allowed then the data rate can be speeded up considerably. The
important factor to consider now is the minimisation of the
impact of such data errors.
Information theory
The main problems experienced in the early days of commercial
automated mixdown systems using the audio machine for data
storage find their root in information theory. In one form, it states
that the amount of error -free information passed in unit time
through any communication channel depends on the applicable
signal-to -noise factor of that channel. If the information is
transmitted at a level which is effectively infinite compared with the
background noise, then obviously complete intelligibility should
result. However, if the channel is momentarily broken for any reason,
this may coincide with an important data character which may be
lost or degraded in some way. Alternatively, when the information
is sent at an infinitely slow rate compared with the rate of the
disruptions on the channel, once again perfect intelligibility
should result.
This far the boundary conditions have been set out; the real
world lies somewhere in between.
Taking the level of transmission first; all dedicated magnetic data
recorders record their signals at full medium saturation. The
current passed through the record head windings is sufficient to
32
STUDIO SOUND, MARCH 1977
Data rate
To memorise the settings of the controls of a system, each
control must create a signal which tells the outside world where
it is at any one moment. In audio consoles, the safest signal to use
is a voltage which varies at the fairly slow rate of the control's
movement and constitutes a dc level when that control is static. For
recording as a digital signal, the dc level is converted to a digital
word in an a to d (analogue to digital) converter. This is a device
capable of producing proportionally ascending steps of voltage,
each step recognisable as a set of digital 0's l's with a binary
numerical value equal to the instantaneous level of the incoming
signal. These can now be stored as data. If several channels
are to be processed, each one can be given a distinct binary code
which is called its `address', and prefixes the stored data. An
8 -bit binary code on eight parallel wires gives 256 different
combinations. If 256 different levels of 256 different controls have
to be stored, each one can be represented by two 8 -bit words
or bytes: one for the address and the other for the data.
To store bytes on a data recorder, they must be converted
from parallel signals on eight wires to serial signals on one track so
that the signal on wire number one is the first pulse encountered
in the data stream and so on. In the reverse direction, when the data
stream is replayed, it is first reorganised to parallel form and,
assuming that the address arrives first, that address activates a
d to a converter which recreates a dc level appropriate to the digital
word which follows.
To estimate the rate of data generation, the mode of processing
must be considered. If each of 256 controls must be encoded
once per second and each must be encoded to 8 -bit accuracy
(256 possible levels), the data rate will be:
256
functions as
8
bit address
_
(8 x 256)
+
(8 x 256)
and 8 bits data
=4096 bits /s
If the scanning must be done at 100 times/s so that continuous
control movement can be regenerated as a virtually continuous
replica, the data rate will be 409 600 bits /s. Clearly, such high data
rates just aren't on. Even assuming that the data can be recorded
by using a special code which only requires the same bandwidth
as the data rate itself, ten scans/s is still going to require
40 kHz bandwidth.
More reasonably, supposing 16 controls are scanned at ten
times/s, the data rate will be:
16
functions
scans /s
bits address
bits data
10
4
8
=10x {(4x16) +(8x16)1
=
1920
bits /s
So it should be possible to record 16 control status on an audio
an error has occurred. Parity checking, as this technique is called,
reduces the incidence of errors quite dramatically and only
introduces a certain roughness of control movement owing to
erroneous information not being passed through.
Data storage
The remarks about keeping the audio machine scrupulously
clean and aligned and not allowing the tape to be touched, if
ignored, can have quite disastrous consequences because low
recording levels must be used. Dust and dirt adhering to grease
cannot be recorded through, resulting in increased error rates.
This problem dogged the early automation systems; some
recording studios are not renowned for cleanliness and some do not
align machines as often or as accurately as they should. The
results of poor data track error rate are sometimes fairly pernicious;
fades, initially recalled as smooth, progressively become rougher
as more data is lost, quick cuts to remove mistakes can stop occurring
altogether or stay down much longer than previously
programmed. The quick cure for these problems was to increase the
data record level, often to peak and beyond, while ping ponging
nearby audio tracks away from the heavy crosstalk areas around the
data tracks.
Other methods of nullifying data faults were tried. The simplest
of these is to send all the recalled data back through the d to a
converter, smooth out any roughness in the dc produced by lowpass
filtering and then take the smoothed dc back through the a to d
converter for subsequent storage. This technique was used on
a number of automation systems produced during the early 1970's.
On the face of it, the technique does produce smoother recalled
control action and, as long as the number of generations the data
track goes through is severely limited, the delay produced by
slowing the rate of change the data can cause will not be
immediately noticeable. If a complicated mix is attempted with
several updating runs it must be borne in mind that all previous data
will be delayed by the a to d/d to a conversion and that recently
recorded data will in fact lead old data in time.
Basic information theory still holds with the analogue smoothing
types of systems and, as shown above, 16 functions to 8 -bit
accuracy is still the practical limit for reasonably error -free data
storage on the master tape, assuming regular maintenance and
highly circumspect tape handling.
To increase the number of functions handled, the only practical
solution was to record the data at saturation, or use a slaved data
machine via a synchroniser. This last solution was finally
adopted by a number of studios who had bought early automation
systems either as packages or as inbuilt facilities. The only
problem with the slave machine technique was that the machine
usually used was in less than optimum condition for data storage,
tending to be an old valved 4 -track dug out from the cellars,
or a semi -professional machine pressed into service and often quite
incapable of reliable data recording as such. To understand why 34)-
machine with a reasonable error rate even using a quite low
recording level. In fact, using good quality tape on a machine
in perfect alignment where the face of the tape is never allowed to
come into contact with any contaminant, error rates of 1 in 10°
bits should be possible, ie one should expect only one bit to
go awry in one million bits of recording. Thus on a 16- function array,
scanned 10 times /s, only one error should occur in 8.7 minutes
of data recording.
1
000 000
seconds /error =520.8 seconds /error =8.7 mins /error
1920
If the error concerned is the least significant digit in one of the
data words for the control level then it will go mostly undetected.
If, however, an open function's address is confused with that of
a closed one, then the error will be very noticeable indeed since the
system then opens another channel. However, one thing is certain:
errors will occur and all that can be done is to minimise
their impact.
By adding check bits to the data byte, some of the data errors
can be eliminated. If the number of 'l's in the byte are counted and a
further bit added at the end, which is one if the count is odd and
0 if the count is even, then the calculation may be performed again
on the replayed data, and bytes ignored if the check shows that
33
CADAC APPROACH TO AUTOMATED MIXING
a proper data recorder was not usually bought, one must realise that
a studio's automation system had by then given so much trouble
and caused so many heated and vitriolic arguments between
producers and engineers that spending any more money on the
system was regarded as useless, and maintenance staff had to use
what was available.
The further thinking equipment manufacturers quickly began
to realise that the promise of expansion of the very simple early
systems to accommodate many more functions simply was not going
to be possible and totally different solutions to data storage
problems would have to be sought. Any computer engineer looking
at the early methods of data storage adopted would, and probably
did, raise eyebrows of surprise finding that media with error rates,
which he would find totally unacceptable, were being used to
store quantities of data that were quite astonishing.
The first and most important task was to reduce the enormous
volume of data. During a mix, several controls are unused or
set and largely forgotten. Real time storage requires that the status
of all controls be known, stored and recalled at any instant. Even
using master tape storage it would be possible to slowly scan
all functions during a lead -in to the material to be mixed and then
only record those changes which occurred afterwards. Such a
degree of data compression would ensure almost error -free
operation. The only snag is that the material must always be started
from the beginning to ensure that the picture built up at any
instant reflects all the changes that have taken place up to that point.
No one seemed very keen on a system that had to run through
ten minutes of playback simply to get the coda just right. But the
idea was, in principle, a viable proposition. All that was left was to
find a store agile enough to be able to run through all the changes
that led to the desk status at any instant when that instant was
selected on the master tape. Further the store must be portable and
non volatile.
Four candidates for the medium were proposed; each has its
benefits and disadvantages. Reel -to -reel data tape is the
first but must be discounted simply on cost grounds, in that a
computer grade reel -to -reel mechanism is not available at a
reasonable price. Nor are they particularly quiet owing to the use of
pneumatic loop storage. Data cassette is a real possibility in that
using two mechanisms in interactive mode, one recording new
data while the other replays the previous attempt, does provide a
fairly agile store. The only drawback is either that of capacity
or error rate. Tape guidance in cassettes is still a problem in that,
given the very confined space around the head assembly, there is
no room for high precision tape guides of sufficient length to ensure
complete absence of wander. Medium utilisation tends to be rather
low for this reason; recording density is kept down so that a
reasonable error rate is obtained. At this point it should be
remembered that the store must be as near perfect as possible since
an error made early in the build -up of the desk's status may not be
corrected later, and in the extreme be carried through. This
apparent fault does have one good point: such errors when they
occur are obvious and, thus, easy to correct rather than being
cumulative or ephemeral as described above.
The third candidate was the true data cartridge with inbuilt
drive mechanism designed and made by 3M. Machines to drive
DC 300 cartridges were rather expensive, and to use two mechanisms
in interactive mode becomes prohibitively expensive. On the
available drive mechanisms researched, the speed of the tape
movement is also kept as low as possible to protect the medium
which, although a very wise precaution, tends to make the store
rather sluggish in response to search commands. The error rate and
capacity are reasonable in that four data tracks can safely be
stored per cartridge, each track taking the data from about 20 -30
minutes of mixing time. The error at this density although not
quoted on the literature appears to be around 1 in 10a from
interpretation of claims made. The criticisms of the cartridge were
mostly aimed at the available drive mechanisms. Owing to speed
limitations on search and shuttle modes, it was found that some
fairly surprising techniques had to be used to keep the master tape and
cartridge in close sync. One system proposed a synchronising
code which could be read by the housekeeping circuitry in the
storage processor even when the tape was being spooled fast. In
order to do this, all the replay amplifiers in the tape machine
34
STUDIO SOUND, MARCH 1977
had to be modified to increase their hf response. Alternatively a
dedicated wide replay bandwidth guide track cleared by ping ponging before mixdown was done on tapes from outside. Spooling
had to take place in contact with the replay head and special cut
circuitry added to those tracks which were not involved with
the timecode track.
It is not known if such a system has ever been implemented but
the fast spooling of high energy tape across heads is not particularly
likely to lengthen head life owing to the uneven wear that usually
results. The other major drawback of using any single data store
which does not run in real time is that of anachronism. Supposing
30m of data tape are used to memorise the intro of a piece of
material and, while listening through the middle section, it is realised
that two or three overdubs are going to be necessary; the middle
is left and the end is worked on consuming another 30m of data
tape. Since the controls were not moved during the middle section,
no data is stored, so the data tape contains the beginning and
end without any room for the middle. Assuming that the middle
section has been left because it is complicated and will consume
around 100m of data tape, it is unclear how the first try at memorising
it can be done when the 30m of store containing the ending's data
are well passed and must be tacked on the new end to maintain
real time sync, even though the start of the 30m end piece is 100m
back down the tape. Obviously if a second mechanism is used
the problem of anachronism cannot occur since the present store will
carry on while the previous store waits to produce its data at
the right moment. Altogether the data cartridge is a most useful
device and will be used extensively when the price and
flexibility of mechanisms allow.
The final candidate for storage is the floppy disc system developed
by IBM as a convenient means of non volatile high agility store.
The point about the disc is that the same information keeps being
made available so, if an error is found in the last try at replaying it,
assuming a reasonable buffer store (enough for say lOs mixing),
the disc can look at the same data 60 times to estimate the possible
data faults that could have occurred before the erroneous data
has to be used. The processing circuitry that lays the data on the
disc performs a set of calculations which result in a certain digital
word being written into store just after each block of mixing and
address data has been memorised. When this data is recalled,
the same calculations are performed again and if there are any
disagreements the entire block is dumped and read again (just like
parity checking but over a longer block of data). The most likely
cause of such an error is a small particle of dirt on the disc surface
which will be wiped off before the next attempt at reading. If
the contaminant is grease, it may take several passes to clear
the fault, hence the use of at least a lOs buffer.
In many ways the construction of a disc store mechanism is
more complex than a cartridge drive. However, owing to an
enormous price battle for supremacy in the disc store market, unit
prices are in fact extremely low. For these reasons it is obvious that
on price and performance grounds, disc storage is vastly preferable
to any other. The only remaining problem is capacity. The
original IBM format for applying data to the disc is immensely
wasteful in that large gaps are left to indicate the start and end of
pieces of data, and the dividing up of the disc into storage areas
is accomplished by information pre- recorded on the disc. Although
the format suited IBM, it does not suit the automated mixdown
process. A floppy disc can hold over three times the IBM standard
capacity by intelligent use of the medium, and stores which use the
extended format are now available. It is interesting to note that the
three most recent entries into the console automation field all
use disc stores.
Mnemonic mixing at Cadac
Under consideration for some years (see STUDIO SOUND May '72),
Cadac's programme to convert a standard audio console to
voltage -controlled operation was realised in March 1976. Initial
studies prior to that date had shown that most of the systems already
on the market had serious drawbacks in several areas.
The first and most basic problem to be solved was that of
voltage control itself. With one exception all the proposed or
available systems used the classic voltage -controlled amplifier whose
advantages and disadvantages are too well known to be reiterated
here. Suffice it to say that if Cadac had used classic voltage- 36 O.
THE ONLY COMPLETELY FLEXIBLE TIME CODE
EDITING /DUBBING SYSTEM DEVELOPED WITH
THE AUDIO ENGINEER IN MIND
NO
nasty square waves to worry you
NO
crosstalk problems
NO
Tape in contact with heads whilst still recognising
tape position
NO
complicated and expensive modifications to existing
machines to interface with maglink system
NO
special requirements to record sine -wave based
code on any audio recording system or material
Now fully compatible with SMPTE EBU time code
Now manufactured and marketed solely in the U.K. by:
ARLTD
AUDIO PERIPHERAL LIMITED
ERNCROFT WAY
TWICKENHAM
MIDDLESEX TWI IDA
TEL 01 891 -7770
35
CADAC APPROACH TO AUTOMATED MIXING
modules are simply run in parallel from low current busses. When
more than 50 modules have to be driven, without interaction,
from any of the command busses, it is not hard to see that a high
input impedance at the command input ports is essential. Using the
cmos series allowed a very comprehensive logic system to be
devised without producing large amounts of heat and buss loading
problems.
The basic commands are `ISOLATE' where the fader controls
the audio via the V-CAT and the voltage corresponding to the
fader's position is ignored by the store. `WRITE' which is identical
to isolate except that the position voltage is stored for later
retrieval. `AUTO REPLAY' where the voltage replica of the faders
position is used to control the audio passing through the V-CAT.
Using these three commands, the engineer can rehearse a passage,
store the mix created when it is encouraging and then listen to
the result.
Each module also has a `READY' button which allows those
modules selected as `ready' to be placed in `write' when a central
control or a roving switch is closed momentarily. A second switch
closure reverts the ready modules to their pre-selected conditions.
Other logical inputs to the module cancel any write function at
the end of a mix, and allow all modules to be forced into a
specified function at once.
controlled amplifier technology, some aspects of the console's
performance would have been affected, and the reputation for quality
gained by many years of refinement would have been compromised.
A research programme was launched to find the most suitable
method of voltage control which could be economically incorporated
in the confined space under a standard fader. The avenues explored
included electro-mechanical methods; electro- optical methods,
purely digital methods and mixed analogue -digital methods. Each
contender offered initial promise and each proved unacceptable for
one or many reasons. It should be said also that each method
produced interesting spinoffs in related and non -related fields of
general studio technology, some of which will become available as
products during 1977 and 1978. Finally during a weekend
brainstorming session, the answer appeared and the V -CAT
concept was born.
It may be known that Cadac uses thick film techniques to solve
some of the more intractable problems of signal processing in
console design. Close liaison with the same thick film engineering
facilities led to a unit which fulfils the requirements of voltage controlled attenuation in a confined space and with minimal impact
on the audio path through the gain controlling section.
In the vast expanse of a typical studio console, one may wonder
why space for voltage control circuitry is at such a premium.
The answer is that to produce a system which can be retrofitted to
existing consoles requires the extra circuitry to be packaged in a
module that occupies the normal volume allocated to a fader
and its connector.
The greatest boon to the designer of this type of circuitry is the
cosmos logic series. It consumes next to no power, it is incapable of
switching at massive interference generating speed and it can be
used to switch both digital and analogue signals with logical
commands. Using a simple command buss system to link all the
modules together highlights the other valuable property of the
series -its high input impedance. Most of the command inputs to
To implement the ganging of various faders together so that
they may all be moved up and down in perspective, all that is
required is to mix a variable external voltage with that provided by
the local fader or its stored replica at the V-CAT driving busses.
This external voltage may be derived from another fader or indeed
any external source which is either fixed or varying. Clearly any
logic command applied to the source of the ganging information must
be similarly applied to those faders which are receiving the
information, thus ensuring that the read and write configuration
is constant inside a ganged formation.
In theory any fader could be used to supply the variable offset
voltage. However, using channel faders could result in confusion in
¡ANALOGUE
Q'AUTO SWITCH
---I
I
Ganging system
'DATA
TO STORE
COMMAND
ANALOGUE GATA
FROM STORE
ISO
AAR
WRITE
READY
TO STORE
c
AUpO
OUT
LOGIC
VOLTAGE
GANG
ISO
GANG
GA
WRIT
GANG ANALOGUE
BUSSES
GANG 7
ENABLE
READY
MASTER' PRESENT
AOINS LM:
WRITE
OR
ISOLATE
CANCEL
0
ALT,
WRIT
ALL ISOLATE
INTERPOLATION
CIRCUITRY
REPLA`r
ALL AUTO REPLAY
GANG LOGIC
ALL WRITE
EUSSES
-r--o
GANG 7
LOGIC COMMANDS FORM
CENTRAL CONTROL MOOULE
TO ALL MODULES
GANG LOGIC
LOCA,
36
îAHG SR91CP
STUDIO SOUND, MARCH 1977
STATUS DECODER
AUTOMATED FADER SHOWING INTEGRATION
WITHIN THE DESK SYSTEM
that signals passing locally through that fader would be varied
in sympathy with the gang condition. Further, the presence of two
or more faders sending different gang information would have to be
sensed and allowed for. For those reasons separate gang sending
faders are provisioned, each hard -wired to separate control busses.
Each channel fader can access the various busses from a local
push button command alternately counting through the busses in
order. An external voltage source can cause each fader to assume a
gang status determined by the level applied to an analogue input
to the module. An analogue voltage corresponding to the selected
gang number is also available from the module for storage purposes.
In practice, to keep the intercommunicating lines between the
console and the external store to a minimum, provision is also made
to switch the control voltage input /output ports from the V-CAT
and fader to the gang number send /receive lines, either individually or
collectively so that an external analogue store can memorise the
desk's ganging status for later retrieval.
In order to simplify the desk wiring, the gang logic status is
encoded on to the logic busses as one of 3 dc levels since the three
different commands would require two logic lines if simple binary
accessed by the channel faders if required. In this way, the entire
desk can be faded, channels and gangs, by a single control. The
gang faders can be set up to control subgroup audio if required so
that both subgroup, gang and channel audio can be faded at once.
Echo returns are also functions which are normally automated
and these controls can also access the gang busses, so with echo
returns on a local gang and channels on the master gang via sub
gangs if required, the direct and reverberant audio can be faded
at different rates. While almost all these functions are available by
audio routing, the setting up of a gang control path is a great
deal easier than setting up the necessary audio path to accomplish
the same result.
The other great advantage of ganging is that it allows the
engineer to mix from a central position. He can assign remote
faders to the central gang senders and control his audio levels from
these and the nearby channels without changing the audio
assignments he would normally use. Like the man said: `I have
always wanted ten foot long arms and now I've got them'.
In common with most European mixing consoles Cadac normally
incorporates a separate monitor mixing bank so that when the
session is in progress, a fairly accurate picture of the final mix can be
obtained, and a quick check made on the overall balance by a
glance at the fader bank. One useful technique borrowed from the
Americans is to interchange the monitor and channel faders so
that the monitor mix can be controlled, ganged and, most important
of all, stored as a basis for automated mixdown later, using the
channel faders.
were used. This refinement only comes into its own where a
large number of gang busses are incorporated; however, it has made
the wiring harness surprisingly simple when only seven gang
master faders are incorporated.
The gang logic communication network was designed with two
considerations in mind. One is that the number of wires linking
the system must be kept to an absolute minimum to allow for
retrofitting in the tight space normally available in a console's fader
area. The other is that no form of clocking of data can be allowed
to occur during a mix since the clock waveform would be bound
to be injected into the audio paths unless all data lines were screened,
thus adding to the harness bulk.
As a further refinement, the source of offset voltage on the
gang sending fader is switchable from local reference to external
input. This external input is normally provided by a master gang
fader which is accessed by the subsidiary gangs in the same way
as the channels access the gang senders. This master line can also be
Analogue section
In the module the voltage tapped off the fader is used to control
the V-CAT when the module is in its 'write' or isolate modes.
Since this voltage will be stored digitally via an a to d converter,
provision is made to convert the fader's output into a logarithmic
function. Most a to d converters operate on a linear ramp where
each least significant data bit change is caused by an equal step
up or down the input voltage scale. If the fader's output were sent
460.
SANG
LOG[
GANG LOGIC
LOGIC STATUS
ENCODER
DECODER
VT/EF
FADER
LOGE
'WRITE
DATA TO STORE
OUR
EVER
DATA FROM STORE
A/R
DATA TO STORE
GANG MASTER
ME
DATA
111.1
FRp4 STORE
101°'
450 -A
R
HUI
CHANNEL /ECHO
AUDIO IN
AUDIO OLl
LOGIC DECODER
LOGIC
l
LOGIC
GANG SW
o
S`AiUS
ÉNCODFF
-
VREí
:
1
WRDE/
'WRITE
D
lo
A/R
A TO STORE
ME'ER
I
IA FROM STORE
I
r---i
GANG SUB
AUDIO IN
VCAI
H
AWG
GUT
1
1
I
I
GANGING ARRANGEMENTS
111
GANG
US-
37
AES
56th Convention: a preview
Hotel Meridien, Paris
March to 4.
Contact : Titia Bakker
1
010 31 2154 19911.
The prize for most ingenious design of any piece of equipment
must surely go to hie Electronics for their /E-20A pink noise
generator. When used with the 1E-10A audio spectrum analyser, it
provides a complete audio analysis system. The most interesting
feature is that each unit can be held in the palm of a hand;
fairly amazing when you consider that both can monitor the
spectrum from 20 to 20k Hz.
For those wanting a 'quick audio tester', Laboratoire ElectroAcoustic of Rueil, France offers I different measurement functions
selected by a single knob. It combines Ido, distortion set,
psophometer and attenuator; it also offers wow and flutter
measurement to DIN standards.
NTP are going to show their standard range of vus and ppms
with all manner of display formats. They will exhibit a new version of
their gas discharge ppm. Designated the 177 -400, it is in a
standard module and features 20 dB of additional gain (switchable)
peak hold facility and balanced line. There will be vus 177 -900
and 177 -950; these possess the same mechanical outlines as type
177 -800 but with a gas display. Hopefully, the company will present
a prototype of a filter unit containing 27 i- octave filters for use
as an analyser in connection with a multichannel ppm type 377 -100.
Wilmot Breeden will exhibit the Ferrograph range of professional
tape recorders and the ever increasing number of test equipment
products from that company. The ARAl displays the gain frequency
characteristics of amplifiers, filters, equalisers and tape recorders,
etc, on a 27 cm long persistence crt offering a resolution of
0.1 dB. Frequency range is from 20 to 200k Hz. There will also be
RTS2 and ATU1 test sets on stand.
I
We gratefully acknowledge the help
given by the AES in compiling
this preview.
Measurement
B & K \\ III be showing the following calibration and measurement
equipment: 2429 Psophometer, 3923 rotating mie boom, 2971
phase meter, the 1902 intermod measuring sweep analyser and
generator, the 4400 gating system, the 4416 response test unit for
response measurements on pickup cartridges and other electroacoustic record /replay devices, and the 2131 digital frequency analyser
offering real time octave or third octave. The last two products
are both new.
Microphones
From AKG comes the successor to the ubiquitous D -202, the
D -2279E two -way cardioid dynamic mic. It features a double transducer
40
LIST OF EXHIBITORS
A, B, C: Floor Area D: Demonstration Room
Acousmat Apollo
Electronics
Agfa -Gevaert
AKG
Allen and Heath
Allotrope/Future Film Dev
Amek
Ampex
Audio & Design Recording
Audio Developments
Audio Kinetics
Audiomatic
Audix
BASF
Becker
Beyer Dynamic
BGW
Bruel & Kjaer
Cadac
Calrec Audio
Capitol Magnetic Products
Cetec Audio
dbx
Dolby Laboratories
Eastlake Audio
Electro -Voice
Elipson
EMS
EMT
38
FM Products
B 12
C 02
D 01
A
A
17
25
C 17
C 12
A 24
A 20
A 02
A 36
B 01
C 09
B 02
B 03
A 30
A 34
A 12
B 14
A 03
A 23
D 06
B 04
A 28
C 10 & D 07
D 14
D 06
A 39
STUDIO SOUND, MARCH 1977
Freevox
Girardin
Gotham Export
Harrison
Helios
A
A
A
A
ITAM
B
IVIE Electronics
D
JBL Sound
D
JVC
C
Kajaani oy Electronics
A
Klark -Teknik Research
B
Klein and Hummel
D
Kudelski -Nagra
Laboratoir Electro Acoustique C
Leevers Rich
LEM Materiel Electro
Acoustique
Lyrec
3M (France)
Macinnes (France)
Otari
D 02
C 04
B 08
A
05
26
18
07
11
04 &
A
11
03
01
27
05
15
14
16
B 07
A 13
A 11
C
11
MCI
A
31
Midas
D 02
A 09
A 04
A 29 & D 16
D 08
C 16
A 40
Millbank Electronics
Neumann
Neve
Nippon Columbia
Nordisk Elektroakustik
NTP Elektronik
D 02
05
Philips
C
Publison Audio Professional D
Pyral
A
Raindirk
A
D
Reditec
A
Revox
Schlumberger
C
A
Schoeps Schalltechnik
D
Scully
B
Sennheiser Electronics
Sensitive Audio
D
Sescom
Shure
Soundcraft Electronics
Special Audio
Spectra Sonics
Stanford
Stanton Magnetics
STR
Studer International
Telefunken
Trident Audio Developments
Tweed Audio Electronics
Wandel & Goltermann
Wilmot Breedon
Woelke Magnetbandtechnik
Zoot Horn
13
35
32
02
33
07
37
31
10
17
A 19
A
01
D 05
C 03
A
15 &
C
13
B
13
A 06
A
B
A
A
C
B
A
C
38
06
08
10
08
09
22
15
A
21
ASK THE MAN
WHO
BUILDS THEM
If you want to find out wha:'s new in lathes, ask Larry Scully He
has designed "THE LATHE ", a mastering unit which is years
ahead of anything else on the market. RCA discovered this pact
when they were able to increase the average level by 2.5 db with
the new Scully system. Another acrantage is service and partssupport
it's right here ár. Europe, not across the ocean. For all
the details, talk with Larry or any of the boys at Scully. Their
',reputation tor quality manufacturing dates back to 1920. but
their thinking is 1980.
...
L. J. Scully Manufacturing Cotp., 138 Hurd Avenue, Bridgeport. CT 06604 Telephone 203 368 2332
Represented by: MCI (Professional Studio Equipment) LTD., MCI House, 54-56 Stanhope Street London NW 1 3EX. 01.38E
SEE "THE LATHE AT THE PARIS AES SHOW
7867/8
AES 36th CONVENTION
:
A PREVIEW
Sennheiser sound effect Vocoder VSM 201
ARA
1
frequency response tracer from Ferrograph Professional
with an associated crossover network at 500 Hz. The rest of the
product range remains largely the same.
Beyer Dynamic have two new products. The first is an
electrostatic stereo headphone ET1000 together with power supply
N1000. The second is a loudspeaker simulating earphone LSE1.
Unfortunately, there are no further details available.
Calrec are to show examples from the L series of broadcast
consoles in addition to the standard range of microphones
manufactured by that company.
Neumann will show the complete range of microphones including
the QMG9 quadraphonic mie and the dummy head KUSO. Other
products at the exhibition will include the SX74 cutter head for disc
mastering, a rumble meter, as well as other ancillary products
for the cutting room.
Schoeps manufacture superlative microphones; the entire
product range will be shown including a new miniaturised mono
mixer with phantom powering. They intend to introduce a
stereo mie complete with all accessories.
Vocoder. It performs a spectral analysis with a set of filters whereby
specific envelopes are formed for each frequency band. The
overall loudness is also measured, resulting in a series of integrated
voltage envelopes which can control a bank of generators
producing either white noise or frequency tones. Since these may be
given a frequency offset, speech inputs may be modified both in
pitch and tonal quality. The vocoder may also be interfaced with a
conventional synthesiser. This stand sounds interesting.
Mixers
Allen and Heath will show their full range of consoles including
the new SD 12/2. However, the real interest on the A and H
Audio
Shure M615AS audio analyser with frequency response analysing mie ES615
together with the new SR107 audio equaliser
First introduced at the Los Angeles AES, Shure will show
their new equaliser M615AS, which incorporates a pink noise source,
octave band analyser and measuring mic. It is intended for use
with the SR107 equaliser for fast room eq for bands on the road.
There will be a new stereo cartridge, the M70B, which tracks at
3 grams. Shure will also exhibit the full range of microphones.
Normally associated with microphones (which in any case will
be present on the stand), Sennheiser will present a VSM 201
40
STUDIO SOUND, MARCH 1977
12
channel 4 group MXT 1000
stand centres around non -mixing products. There is an eight track
25 mm mastering machine, a forward delay limiter and an adt
black box. These last items represent a considerable departure
for the company's product range.
Amek are showing their M3000 range of consoles providing
either eight, 16 or 24 inputs with four -band parametric eq on each
channel. A two thumbwheel routing arrangement offers up to
16 output busses; more than enough for recording applications. Other
models on show include the M2000 series of 16/8/4 format as
well as a straight 16/2.
Audio Developments will demonstrate their new ADO 45 Pico
mixer offering six/two interface, internal rechargeable 12V battery
with a dc to dc converter for 24V operation. There is a three -band
equaliser on each channel.
Audio Kinetics (UK) Ltd is a company run by Ian Southern of
Sonaplan fame. It will exhibit a large console `integrated with a
multitrack tape machine'. The 4000 console has 40 inputs with 32
42
MILL BANK
Jr,
PARIS®
March 1st -4th, 1977
designers and
manufacturers of professional
audio equipment
ITE
MILLBANK
Millbank Electronics Group Limited, Uckfield, Sussex. TN 22 1PS. England.
Uckfield Sussex.
Telephone: Uckfield 4166 0825-4166)Telex:95505 Millbank G Cables: Euraudio
Millbank- leading Europe by Design
41
www.americanradiohistory.com
AES 56th CONVENTION: A PREVIEW
group busses and features a vca compressor expander,
plus an 11- control parametric equaliser on every channel. Group
routing is digitally displayed including the eight vca subgroup.
It also features Supercue
cue -switching system operating in
conjunction with machine control remotes provided on every channel.
This claims to speed up drop ins. The accompanying WOO series
24-track machine features track cards incorporating the noise
reduction controls. As a result, Dolby and dbx modules simply
plug in, minimising installation and routine maintenance.
Never short of ingenuity, Southern has created a learning
autolocator which would seem to offer even more than his own, very
comprehensive, XT14 autolocator. For use with either Studer
or 3M machines, it features a microprocessor capable of doing a soft
shoe shuffle between up to six aim points, improving its
accuracy with every operation.
Audis will be showing an MXT-100 modular mono pa/broadcast
mixer. The MXT-200 and 800 series of equipment will also
be shown.
Naturally, Cadac will be showing an example of their desk
automation. Fitted with V-CAT vca modules, the quad /stereo
console has a cmos switched routing arrangement controlled from a
central position on the console. The exact routing elected is
displayed by a four -figure digital display on each channel. The
company will also show a cpu and floppy store for use in
conjunction with the console. For further details see page 32.
Cadac have introduced a limiter compressor based on the
V-CAT module, which will also be shown.
Helios will emphasise their custom-building facilities for recording,
sound mixing and broadcast consoles. A particular focus will be
given to 'flexibility of approach
and a willingness to meet
specialised broadcast specifications throughout the world'.
Kajaani Oy, the Finnish console manufacturers, will be showing a
Model 10EA 12 channel input /two output, two foldback
broadcast mixer.
MCI will show the well known J1-124 multitracks and the
increasingly well known 500 series of automation ready consolesvariously known by some, especially Dag Feiner, as the 'Quiet One'.
Neve will have on stand an 8058 28/24 compact console which
will be shipped after the exhibition to the Centre George Pompidou
for installation. Probably more important, they won't have a real
live NECAM system. Instead, there will be a slide and video
tape presentation with Geoff Watts on talk over.
-a
For the Paris AES, Philips will be going heavily on pa installation;
sound reinforcement desks will be represented by the LDC15 and
LDC25 There will also be ancillary products such as cctv, paging and
internal communication, all of which find special application
in theatre sound.
Following US philosophy of desk design using all channels as
inputloutput modules, Raindirk will show representations from the
new Quantum range. Available format.; are 40, 32 and 24. There
will also be a selection of Raindirk Minis such as a 10/4, 18/8,
etc. The latter features 16 track monitoring.
...
Philips LDC 25 mixing desk at the Centre Pavoissale, Geneva
Soundcraff Series 2 console, Demo room D05
At the last two AES exhibitions, Soundcraft have always provided
excellent demo facilities for their range of desks. This year
should prove no exception. They will be doing 16 -track mixdowns
through their series two console. This is available in several
configurations from 12 to 24 inputs /unspecified number of
output busses.
Spectra Sonics will show the 610 Complimiter which is a revised
version with new non -glare vu meter, bi -polar power supply and
improved electronics. They will have on the stand 1026 -26 mixing
desk featuring 26 input /output modules; there will also be a small
rack-mounted mixer with six switchable inputs.
Trident are to show the Fleximix mixer system for either `budget conscious studios or high quality pa' which can be expanded
from small mono to 40 input /ten output with 24- channel monitoring.
These mixers are housed in a flight case. The company will also
show the CB9066 three -band parametric equaliser with high and low
pass filters as well as a bank of led meters using ten green and
four red leds in column a.ray; together these are claimed to give
an indication over nearly 40 dB.
Tweed are showing three mixers: a 10/4 with metering and
monitoring on all channels, a 12/2 standard console featuring
balanced inputs and outputs, a 20/4 desk specially constructed for
Border Television, Carlisle. Also shown will be a Twin Telephone
Hook Up for live bore in programmes which claims several special
features as well as twin power amplifiers and a compressor /limiter.
Zoot Horn will show the PMR 2 series of mixers which offer
equalisation, compression, echo and cue busses and other features.
Power amplifiers and monitors
BGW intend to show a Model 100 `professional' amplifier
offering 30W /channel into 8 ohms or 44W into 4 ohms. It claims to
provide 80W in mono bridge connection. There will also be a
high performance domestic preamp and the 500D power amplifier.
JBL have proved that they can make an amplifier, the 6233,
with the same studio monitoring design standards as the massive 4350
speakers of which the company has sold more than a few. The
amplifier claims 300W/channel into 4 ohms with less than 0.05 % thd.
44
42
STUDIO SOUND, MARCH 1977
www.americanradiohistory.com
Les ROLLING STONES,
LEU ZEPPELIN, ELP
et Gien
d'autres
pourquoi pas vous ?
Le DC 300A délivre jusqu'a 500 Wrms par canal,
dependant de la charge, à des taux de distorsion
inférieurs à 05 %. Sa bande passante s'étale bien
au -delà de J'auditibilité et son rapport signal bruit
(110 dB endessous de 150 watts) en fait un favori de
la
majorité des groupes et studios d'enregistrement.
AMCRON existe depuis
25 ans.
Les premieres creations destinees aux professionnels du son
ont tres
vite interessees les laboratoires de recherche, stations de radio et
studios d'enregistrements.
renommee s'etend maintenant aux musiciens et amateurs de tres
haute fidelite.
Sa
La Societe
avec la
MACINNES travaille depuis
Societe AMCRON.
IO ans en
etroite collaboration
MACINNES vous parlez ditectement au fabricant
Ceci vous assurant donc le meilleur service possible et la mise a
disposition d'un service technique competent.
En vous adressant a
IMPORTATEUR EXCLUSIF
MAC.INNES ;'FRANCE
Rue Botzaris, Paris. 19
Tel: 206 60 70 et 206 73 61
18
43
AES 56th CONVENTION: A PREVIEW
It uses a switching mode power supply which has brought down
both size and weight. For instance, it weighs only 15.7 kg.
Macinnes France are agents for Amcron products. Accordingly,
they will show the product line of Crown power amplifiers, unchanged
and familiar to all, as well as the latest addition: an 11 -band
graphic stereo equaliser EQ2. The most interesting feature is a
control which offers up to half an octave offset to the centre
frequency of each band.
Millbank produces specialised pa gear; one of the company's
products include a PAC system comprising a single mainframe and
slot -in modules to build up custom pa system. Other areas of
manufacture include discotheques and leisure products.
The French company Sensitive Audio manufactures a triamplified
system of 800W total power; this is type OBS1. With that kind
of power the company name seems a slight misnomer. Still, it sounds
They also provide
about right for monitoring music concrète
acoustical treatment for studios and control rooms, etc -how
singularly appropriate.
Stanford of Bruges, Belgium, manufacture audio mixers and
power amplifiers for domestic and discotheque use. They also cater
for live entertainment. As such, they incorporate phono, mic
and tape recorder inputs to the usual unbalanced line impedances.
Power amplifier ratings range from 50 to 150W /channel.
...
Sound processors
Introduced at the last European AES, Audio Design and Recording
will feature the Scamp series of rack modular, low -cost sound
processors at his show. There are three major additions: the first is
a compressor module SO/; the second is led display column;
while the third, SO4, offers parametric equalisation in three separate
sections with overlapping coverage. Also there will be the very
versatile F760-RS offering compression, expansion and limiting in
any combination -very useful.
Dolby will be exhibiting their established product line of noise
reduction equipment including the full range of cinema processing
equipment. The CP50 (new model) provides an economic update
for cinemas with optical equipment; the CPI00 is a control centre for
RV
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Trident Fleximix 19 input -10 mixed output
processing all types of soundtrack.
There are no new surprises from dbx. They will be showing a
12/24 channel mainframe, K9 -22 dbx replacement for Dolby
Cat 22; also on show will be 187, 154, 192 and 142 units.
Tom Hidley of Eastlake Audio will be showing Tom Hidley,
while Scenic Sounds will exhibit David Hawkins freebie tea shirts as
well as the Marshall Time Modulator and the MicMix Time Warp.
Both the latter units effect the time domain with all the
usual implications .
EMS will be demonstrating the Vocoder as well as the more
regular Synthi synthesiser products.
From EMT there are two products of high interest. The first
is the EMT250 electronic reverb introduced at last year's Zurich AES.
The second is the EMT950 direct drive studio turntable. No
further details available.
Klark-Teknik are to reveal, for the first time anywhere, a range
and that's all
of professional digital reverberation and adt units
they're saying about those at the moment. However, there will be
the full range of graphic equalisers: DN27, DN22 and the DN15. The
first two supersede all earlier models while the last is entirely
...
44
STUDIO SOUND, MARCH 1977
Klein
&
1-fummel UE200 Equaliser
new. It incorporates a consumer- looking preamp within a dual
11- frequency unit. The quoted performance of all models include:
less than 0.01 % the at any slider position; less than 90 dB of
noise over the audio bandwidth (20 to 20k Hz) relative to the output.
Klein & Hummel will exhibit a two -channel seven -band
parametric equaliser mainly intended for control room equalisation.
Each filter can be tuned over the range 15 to 20k Hz. Designated
type UE200, it features stepless cut /boost and variable skirt shape on
each band to enable optimum band interaction.
The same company will also be showing a new tri- amplified
monitor speaker, the O 92. The total power is about 210W,
producing an spl of 105 dB at 2m.
Tape machines and tape
Agfa won't be introducing any new products this year;
their display comprises PEM468 and PER525 tape.
Ampex will exhibit both the ATR 100 and MM1200 mastering
machines together with sync and frame tagging EECO equipment
which provides an interface with vtrs, etc. The range of
recording tapes will be shown.
The Audiomatic Corporation manufactures duplicating equipment
featuring record electronics integrated with the reproduce head
assembly. This allows ready interchange without having to go
through the usual procedures of electronic alignment at every head
change. The company will also show a Superscope automatic
cassette loader and other accessories.
From Capitol Magnetics will be the complete line of professional
recording tapes, discs and cartridges. They would draw attention
to the properties of their Formula 19 inevitably high output,
low noise back -coated mastering tape.
Cetec are to show their loudspeakers; however, the main exhibit
will be a Gauss high speed (64:1) duplicating system which is
claimed to dub frequencies up to 14 kHz on to cassette pancakes.
ITAM will show their 805 12.5 mm eight -track tape machine
featuring a variable speed capstan from 17.5 to 53.5 cm /s. It uses
plug -in channels and separate sync electronics. They have also
introduced a new transport, the 810. Using 25 mm tape, it offers
either eight or 16 -track operation. It incorporates dynamic braking,
motion sensing, logic control and motor servo, etc.
In addition to the established range, there will be a new flexible
mixer series providing a mainframe into which any combination of
input and output modules may be plugged.
Leevers- Rich/Bias will introduce the Praline 2000. This 6.25 mm
machine is said to be a `highly sophisticated machine designed to
satisfy the most discerning user'. It features dc servo-controlled
spooling motors, dual do servo -controlled capstans, and full ttl logic.
Standard features include varispeed and electronic tape timer.
In the Proline 1000 range, the company now manufactures a
transportable version; this can be supplied with either
servo -controlled or direct drive.
Lyrec are to show both 16 and 24 -track tape machines complete
with all the usual remotes, etc. A cassette duplication system using a
new bin loop master will also be exhibited.
A digital recording system will be shown on the Nippon Columbia
stand. It uses a pulse code of 14 bits arranged to fit standard tv
picture line format. The advantage of doing it this way is that
virtually standard vtrs can be used as the recording medium. The
system on display will provide 8/4/2 channels of audio as required.
Nordisk of Denmark will be showing a machine capable of
playing the BASF Unisette to broadcast replay standards. There
46
THE "REEL"
BEAUTY OF
SCANDINAVIA
TR53
features:
Comprehensive remote control
unit.
Calibrated varispeed.
High overload margin for
modern tapes.
Simple spot erasing.
Fast search function.
Convenient solo
button.
Small compact size.
Ask for our catalogue and distributor in your area:
Lyrec Manufacturing A /S
Hollandsvej 12 DK
Denmark
Telephone +45 287
2800
Lyngby
Lyrec
0
6322
45
www.americanradiohistory.com
AES 56th CONVENTION: A PREVIEW
will also be an automatic information system using Logmatic
cassette recorders running in variable sequence for applications such
as traffic control in airports, etc.
Pyral will show their range of tapes and disc cutting blanks.
In addition, there will be two spectrum analysers; one of which offers
ten bands on standard octave centres while the other has eight
octave bands to 4k Hz and a further six i- octave bands from
6.3 to 20 kHz.
Reditec of Montreuil, Switzerland, are agents for Otani, Midas
and FM products; all the companies will be represented by their
various products. Otani tape recorders will be featured as well as a
master /slave loop bin duplication set. Three Midas mixers will
be shown, the largest of which will be a 30/8. FM display
includes two large power amplifiers.
Revox will only be displaying one new product, the A740
power amplifier. This is a domestic oriented version of the Studer
A68. Other hi -fi products will also be on show.
This year, Studer have gone for the spectacular. They will
exhibit a functional broadcast facility comprising a 089 mixing
console, an A80 /RC master machine, EMT turntables, A68 power
amplifiers, off-air tuners, Loomatic and jackfield. There will
also be a 169 mixing console, a tapelock 2000 synchroniser and
a pilot decoder.
Woelke manufacture, and will show, magnetic recording heads
in all sizes and track formats from 6.25 to 50 mm, one to 24- track.
Several products in the range are new this year. Regarding
CADAC APPROACH TO AUTOMATED MIXING
direct to the converter, half the available data levels would be
consumed by the first 6 dB of fader movement from the top and the
difference between -55 and -70 dB towards the bottom of the
travel would occupy just one data change. If the changes measured
were to be based on a linear scale then a normal a to d converter
would be ideal, but decibels are logarithmic and thus, to represent
each unit change on an audio signal in decibel form, the voltage
step causing that change must have a logarithmically related step
size. Thus if the voltage from the fader is converted to a logarithmic
scale before sending to the a to d converter, equal digital steps
will produce a scale representing decibel or fractional decibel steps,
and the cramped- expanded resolution referred to previously is
eliminated.
There is another solution to this problem which makes life very
much easier for the designer: the control element (vca) is made to
respond to its control voltage in a logarithmic manner; ie its gain is
expressed in dB per volt of control input). The source of this
control is then a linear track fader which is scaled in dB. Thus no
log amp is involved and cost is very much reduced since linear
faders are also easier to make than audio taper ones.
One of the design parameters laid down for the Cadac voltage
controllable console was the provision of a panic button which
reinserted the fader into the audio lines if any fault was suspected or
found in the system. Obviously, if a linear fader is used in the
control chain, this cannot be employed as a level control and so the
standard audio taper unit is fitted together with a wide range
low noise log amp.
At the store, the data is recorded as fixed values; thus on
replay a perfectly smooth control movement will be represented as a
series of steps. In order to smooth these out so that the recalled
fader does not sound as if it is a switched attenuator, simple
integration of the steps or low pass filtering could be used. However,
in order to smooth out small steps and still respond quickly to
large ones, no one time constant or filter function is found to be
exactly right. In fact the CARE system uses three different time
constants which are brought automatically into play depending on
the form of the step function presented to the analogue voltage
control input. The technique of analogue interpolation allows a lower
than normal scan rate to be used thus reducing the load on the
stores.
As will be recognised by any engineer dealing with inept
46
instrumentation, there is an automatic distortion set ME401 using
an auto null system as well as the longer -established ME102
and 104 wow and flutter test sets.
Miscellaneous
There is a portable Dolby noise reduction system custom- designed
for the Nagra IV on offer from Allotrope/Future Film Developments.
These companies also supply a wide range of connectors and
cables as well as the Sescom range of modules and transformers.
Gotham Export Corporation are the export agents for UREI,
Switchcraft, Lexicon, MRL, Allison and Amber. Show exhibits include
the versatile, low -cost UREI 200 level recorder system incorporating
transmit receive modules for automated response plotting. There
will also be an Amber 4400 test set (reviewed in STUDIO
SOUND February '77).
JVC are running a second house for the Raising of Lazarus;
the stand centre point will be the CD4 -50 demodulator for playing
CD -4 records. It features delay time controls for fine tuning of
separation, noise gate for surface noise and automatic 4 -2 switching.
Striking a consumer chord, Stanton Magnetics will introduce a
new version of their stereo wafer headphones with different cushions
`for better isolated listening and better bass response than in the
original model'. They will also show a stylus timer to tell you
when your needle is getting blunt at the end.
STR stands for Standard Telephon and Radio AG. They
manufacture data transmission equipment; on display will be an
Odilog system which features data preservation in the event
of power failure. A vdu shows inputs and terminations.
artistes, a low scan rate may not allow him to cut out mistakes
quickly, as the scanning section will ignore the fader he is pulling
down so hard while scanning all the others. To overcome this
problem, all CARE faders are scanned at a high rate which then
changes to a low rate as soon as appreciable movement is detected.
Thus if a cough, or malediction, has to be removed, the store will
respond almost instantaneously but long gentle fades do not
fill up the store with masses of data.
Since the detection of movement should be done digitally to
be reliable and free of drift, the fast scanning of all channels with the
a to d converter must be done. When it was estimated how fast
the converter would have to be to complete conversions on all
channels during the meagre time allowed, the answer proved expensive.
Ferranti has recently started to manufacture a monolithic
converter which was cheap enough to allow its incorporation on
every channel for d to a duty and fast enough to convert seven
channels on a to d in the time allotted; a natural choice for the
CARE system.
The store
Keeping all the data in its place is managed by a Motorola 6800
microprocessor. Its basic functions are: generation and recognition
of timecode information; initiating and regulating the a to d
scans and tagging these with the relevant addresses; interleaving
the d to a scans and outputting the store data when this matches both
the timecode and address reached by the scan; scanning and
matching the `write' command lines to ascertain whether the data
received is to be stored; checking the digital data for control
movement and checking this movement to see if it is new or
continuous, and adjusting its scan rate accordingly. However, the
most onerous task occurs when a new mix is started when the
ganging must be stored, or set; the desk status stored and set and the
timecode just received matched with that available in the store
using a directory of store location vs timecodes that it writes for
itself.
The details of the software are outside the scope of this article,
but it has been found that as long as a separate 6800 manages
the stores housekeeping, then one microprocessor can cope with all
the routine desk scanning and data shuffling.
The first phase of the programme of voltage control of a
Cadac console is now completed and although the whole process has
taken a reasonably short time a good deal has been learnt on the
application of what is still considered as high technology to the
very conservative world of the mixing console.
STUDIO SOUND, MARCH 1977
www.americanradiohistory.com
Quartz precision. What it's done for watches,
it does for the F400
In timekeeping, quartz accuracy is measured in
millionths of a second. That's precision.
Now, with the F400 from Schlumberger, quartz
precision comes to professional tape recording.
Because the F400's DC drive motor is crystal -slaved
and phase - locked, setting new standards of stability
in tape transport speeds. Better, in fact, than 0.02 %.
With stability like this, the necessity fora speed
control is eliminated.
The slave facilities make the F400 ideal for
integration into computer -controlled systems. The
DC drive makes possible a wider range of speeds;
forward and reverse tape transport; and easily
controllable cceleration and decelerat on.
Other features include modular construction of
both mechanical and electrical components for
easy maintenance, and hard -tipped long -life
magnetic heads.
So when it comes to the latest technology in
professional tape recording, think quartz. Think
precision. Think F400.
COMPTEURS
Schlumberger
COMPTEURS SCHLUMBERGER AUDIO PROFESSIONAL DEPARTMENT
296, AVENUE NAPOLEON- BONAPARTE 92505 RUEIL -MALMAISON TEL. 977.92.23 TELEX 692474
F
47
www.americanradiohistory.com
A question of coincidence
TRYGG TRYGGVASON
Purist technique raises questions of
practical relevance; exponents of a rigid
doctrine sometimes forget that a musical
interpretation is the final objective.
'UNIVERSITY OF EAST ANGLIA
FOR some time now, I have been concerned that the literary
output of theorists discussing microphone techniques for
classical music considerably outweighs that of those actually
engaged in the art of sound balancing. This concern has been
compounded by current thinking, intended to solve the problem of
quadraphonic recording and reproduction which appears to have
been extended from the analyses of purist stereo recording
methods. I consider these analyses to be based on fallacious
premises. As a practising balance engineer, I therefore feel that the
time has come to question the intellectual validity of the premises
of purists teaching the gospel according to Blumlein, in the hope
that any errors inherent in it might not to extended into current
thinking on how best to use the quadraphonic medium. I have
no desire to suggest that the coincident mie system is inherently poor;
I use it where appropriate, although not often, and it is possible to
achieve excellent results with the method. However, the fundamental
attraction of the system to the theorists appears to be its
`purist' adherence to scientific principles -that is, reproducing the
sound that would have been heard at some position in a hall or
studio at the time of recording. However, a detailed analysis is quite
unnecessary; the scientific basis of coincident microphone technique
collapses without more than a cursory glance at the factors
involved. Few would question that the experience of a `live' concert
is electrifying in comparison with the most sophisticated recorded
representation. We need only to place a Blumlein Pair at any point
in a concert hall, which one might pleasurably have occupied
during a concert, and listen to the result via a recording or an
amplification system in the control room; I contend from direct
experience that there is no basis for comparison, and the reasons are
manifold, as I shall try to explain. First, there is a very
considerable, and usually ignored, psychological factor inherent in
one's evaluation of live music -the sense of occasion, the
personality of the musicians, and the ability to see. This is a refined
extension of the pop concert syndrome -fans go to see and
partake of some social atmosphere, and the music may barely be
heard above the `ambient' noise. A recording made of such an
event may have little musical value as the music is probably less
48
STUDIO SOUND, MARCH 1977
important than the occasion and the personalities which are
dominant. Unless we intend specifically to record, as best we can,
such an event -for historic or nostalgic reasons -it is fruitless
to apply `purist' reasoning to the recording of music specifically
for record, as the psychological involvement in the event is entirely
absent.
We have, therefore, the task of recording music in a medium
which cannot possibly do justice to the event. To attempt to recreate
the sound field present in a concert hall via two point sources.
without the psychological and visual factors, in a completely different
room acoustic and environment, is quite impossible -even the
concept is ludicrous, without even asking the question as to why
every loudspeaker and microphone sounds dramatically different, in
spite of close similarities in technical specification. Whatever it is
that theoreticians are proving with pages of mathematics on
sound localisation etc, it certainly has little to do with the totality of
perceived sound. It has been a chronic trait of human intellectual
endeavour to presume to force natural phenomena into contrived and
formulated comprehensible disciplines of their own making. Thus
the rigorous mathematics of sound localisation etc, with which
we are inundated are no doubt unchallengeable on mathematical
grounds, but the most rigorous mathematical proof is worthless
unless the premises are correct.
Noting once again my observation that the perceived sound
qualities in the control room and live sound are quite at variance with
one another, even using first -class equipment, I feel justified in
suggesting that the premises cannot be correct. Whether the reasons
are the psychological ones I have outlined, technological limitations
or whatever, these are of little interest to the balance engineer at
the time he is required to come up with a satisfactory sound quality
in the control room. I am as suspicious of these mathematical
justifications as I am of those applied to matrix theory in
quadraphonics. Here again we are bombarded by mathematical
pyrotechnics telling us, conflictingly, that this or that matrix w ill
sound subjectively best -yet one might be pardoned for a
sneaking suspicion that it is impossible to solve two simultaneous
equations with four unknowns.
The approach of the balance engineer is to admit that the quality
of music heard in the control room is different, for whatever
reason, and simply to make the best of it. The only premise here is
that a rigorous analysis of sound is counter- productive and that
an intelligent use of observed phenomena according to logical
principles is superior. There is never time during a recording session
for scientific rigour, only cause and effect; the variables involved
are far too interrelated for mathematical analysis in a reasonable time.
I do not wish to suggest that I am anti -scientific -this is far
from being the truth. I am simply saying that in a working recording
session of three hours, the variables and their interdependence
could keep a computer happily occupied for many hours, even if the
relevant information could be defined. These variables, incidentally,
extend far beyond sound structure itself; into personalities,
psychology and physical factors which would be exceedingly difficult
to infer. In short, 1 am saying that the translation of a performed
piece of music in a hall into a recorded piece on record involves
a transformation of an event from one medium to another, and the
only common factor is the music itself. It seems to me reasonable
that a record listener is primarily interested in the music itself,
whereas his attendance at the Proms leads to a psychological
shift of balance from the music to the sense of occasion, which
cannot be captured on record.
What then is wrong with saying that we are attempting to
translate a musical phenomenon into a domain in which it alone is
master, and using any available device to enhance it in the medium in
which it is to be appreciated? Is this not better than to enslave
ourselves in our contrived and superficial attempts to order the
real world? For instance, I would suggest that it is entirely possible
for two recordings of a piece to exist, one with outstanding
positional definition and the other considerably worse in this respect
-yet from the point of view of overall quality, the latter may
well be far superior. This observation is another illustration of the
attempts of scientific dogma to take those factors which are
rigorously manipulable out of a phenomenon, and then using these
manipulations to form `conclusions' and `truths' about the totality.
All that has happened is that the analysis has no complete
mapping to the phenomenon, because the postulates are unsound.
Returning to the coincident microphone system, we see that
the scientific justification is lost because a) it can only be correctly
evaluated using headphones rather than loudspeakers because of
the crosstalk problem, b) because of the psychological differences
already discussed; and c) probably because the overall system cannot
accurately reproduce a sound field present in the original location,
for some reason. Thus this `purist' technique is far from being
pure in any complete sense, as in any case our ears will tell us. I have
never been able to see how a theory can be developed or applied
if elements within it are unsound, and it therefore seems that
there cannot be any meaningful mathematical analysis of the
performance of coincident pairs; we are left with only superficial
and doubtful positional location information.
It is important that a balance engineer should have a degree
of fluency in physical cause and effect bases, but equally important
that he keep the domains of the variables involved in a mathematical
representation of these phenomena open. This requires an
unusual sensitivity and readiness to extend principles beyond
boundaries convenient for mathematical analysis. Data is continually
absorbed, but in a diffused sense, as food for the intuition which
is the all-important tool enabling the human brain to obtain
almost instantaneously a solution to a problem which might occupy
a computer for some considerable time. But at the end of the
day all manipulations are in the interests of the music itself -no event
or occasion. Perhaps I should provoke the purists by asking
whether or not it is possible for recorded music to have greater
intellectual integrity musically than does a live performance, in
which social as well as intellectual factors have considerable play?
Therefore, might it not be entirely reasonable to suggest
that recorded music, in which technology is put to the service of the
music alone, is musically speaking `purist' even if there is little
relationship between the recorded and original sound? All halls,
instruments and performances sound different-why then cannot a
recorded sound, which is not identical to the original (which it
can in any case never be) be a perfectly valid expression of a
musical idea? Those of us who care for music, I venture to suggest,
do not need to pretend that we are present at a concert when we
listen- should we include the coughs and other noises of the
audience also?
Yet another anomaly in reasoning remains unquestioned.
If the `purists' are right, we should obtain a very satisfactory sound,
in a performance, by placing a coincident pair perhaps 10 -20 metres
from the orchestra; a position where a listener might be. Yet, for
the purposes of gramophone records rather than live broadcast,
the recorded sound quality with this method is unsatisfactory and
there is general agreement on this. I cannot believe that all
recording engineers are misguided deviants from the norm of the
populace. I think that a large enough number of people have been
involved in recording to represent a reasonable statistical view of
what people want to hear in their listening rooms, and almost
universally, the microphone distance from the source that is used
bears no relation to the average distance of an audience member
in a live performance. In classical music, the distance used, from
performers to microphone (irrespective of mic technique), probably
centres around 3 metres. Where is the relationship between this
distance and the audience distance? Yet, under listening room
conditions, this order of distance seems to create what most of us
seem to consider a `natural' and aesthetically satisfying sound
quality
another omission in the premises of `purist'
theoreticians which is conveniently forgotten. The reasons, of course,
lie in the differences in the two media (live and recorded) which I
have already outlined.
It occurs to me that I might have given the impression that
engineers formulate balances merely to their own taste, and it may
just
be worth forestalling the predictable sense of outrage that such
a suggestion would create. A good engineer formulates his sound
quality not only in accordance with his own judgement, but by
extending the essential sensitivity that I have described to all those
around him- musicians, producers, tape operators and visitors
order to extract any information that might be useful. The final
result is not often obtained as a consequence of unilateral decisions
by a recording engineer, if he is other than mediocre
is the
best possible statistical straight line through the sensitivities of all
involved. Our subjective evaluations, however, are capricious in
the extreme; we may say one day that something is good, and another
day that it is bad. This frequently happens with artists, who,
without the listening experience of those involved in the recording
industry, cannot understand why it is that things sound different
in different rooms, with different speakers, and perhaps on different
days. Engineers, who are accustomed to collating such data in
their minds, are usually able to weave their statistical straight
line through such difficulties; yet a single session lying well off the
line can be exceedingly problematical.
It seems to me, then, that the qualities of sound on record are
a reasonably statistical representation of that which a relatively large
group of people have wished to hear-within the limitations of the
competence of those who have had to achieve it. What is certainly
not the case is that a handful of engineers or producers have
foisted upon the public a kind of sound which, for some reason,
differs radically from that which the record -buying public
wishes to hear.
One important observation: the indiscriminate use of multitrack
techniques has, it seems, resulted in a depletion of the sensitivity
which an engineer must have to take full advantage of all useful
factors during a recording. Inevitably there is a tendency to
place microphones closer to instruments in order to achieve
maximum track separation, with a view to achieving a satisfactory
balance later. To some extent this is wise insurance but inherent
is also the danger that too much of the aesthetic of the balance
is trusted to the resources of technology. This proposes that
any microphone array can yield a superlative sound quality if enough
time is available to manipulate faders and equalisers later. It is
not unlikely that coincident microphone adherents may have become
more firmly entrenched in their ideological positions, partly as a
result of multitrack balances in which the microphone arrays
were not optimised at the time of recording.
-in
-it
Forgetting multitracking altogether and considering only a
direct stereo mix, very small alterations in the positioning
of microphones and/or musicians result in dramatic differences in
sound quality; microphone types yield equally dramatic differences.
To create, from this amorphous plasma of variables, a multi -mic
system which yields a subjectively satisfying result is difficult, but
possible, and, in my opinion, superior to a purist stereo microphone
recording of the event in most cases. Since I have said that any
instrument cannot sound in the listening room as it does live, is it not
a little pointless to cling to this so-called purism? Is it not more
constructive to subjectively evaluate the quality of different
microphones and to use them in any way we can devise to obtain the
best possible subjective result in each individual case?
But I think the time has come to summarise.
The reproduction of live musical sound sources in a listening
room environment, with any accuracy, is currently impossible. We
who are involved in making records have therefore but one clear
duty to music and that is to transcribe it to a listening room
environment in whatever manner we can devise which is most
appropriate to it and its appreciation in that environment.
If technology were refined enough to permit it, we might
directly transcribe the event in physical terms, and leave it at that
though, no doubt, the psychological factors would still cause
problems. As it is, technology, analysis and scientific endeavour have
consistently failed to provide the essential equipment for `purism';
we are inundated with technical specifications -both professionally
and in the hi -fi market -which tell us little about the performance of
the specified device. Our senses, on the other hand, directly
comprehend the phenomena, and I see no reason to abandon them
merely because we cannot fossilise them in mathematics. In
the circumstances, we can hardly be blamed for retreating from the
mathematics and science that so elegantly misrepresent real
phenomena, and preferring to rely on our own senses, intelligence,
and devotion to music.
49
Survey: power amplifiers
Power output: 100W rms, both channels driven.
Input impedance: 25
Nominal output impedance: 852.
Damping factor: 20 adjustable.
Power bandwidth: 20 Hz to 20 kHz
Gain : 1.19V for rated output.
Hum and noise: 110 dB below rated output.
Distortion: below 0.05% to rated output. Im
(SMPTE) better than 0.05% to rated output.
Other features: dV /dT 6V /us.
0.2 dB at
rated power.
Protection : short circuit cutout.
Input impedance: 100 kn.
Gain: 1V for rated power output.
Hum and noise: 94 dB below rated output.
Distortion : less than 0.1 % thd and im (any level and
Future surveys include monitor
loudspeakers (May) and
synthesisers and special effects
units (July). Information for
survey inclusion should reach
this office (address p3) no
later than six weeks before the
issue publication date.
mixture between 20 Hz and 20 kHz) at rated output.
Other features: vu meters. dV /dT 15V/us.
Connectors: 'plenty of input /output terminals'.
Power requirements: 100V to 240V ac.
Dimensions (whd):
Weight:
445 x 152 x 355 mm.
19.5 kg.
ALTEC
See review p74.
k52.
DC300A
Number of channels: two.
Power output: 150W rms both channels driven.
100W rms/1 S2
500W rms /2.552
200W rms /852
one channel only.
Nominal output impedance: 852.
Damping factor: 200.
Power bandwidth: dc to 20 kHz ÿ1 dB.
Protection: full output protection.
Input impedance: 10 kS2.
Gain : 1.75V for rated output.
Hum and noise: 110 dB below rated output.
Distortion : im and harmonic below 0.05% to rated
output.
AMCRON
Amcron Inc, 1718 West Mishawaka Road,
Elkhart, Indiana 46514, USA.
Phone: (219) 294 5571.
UK: Macinnes Laboratories Ltd, Macinnes House,
ACCUPHASE
Kensonic Laboratory Inc, Japan.
UK: Pyser Ltd, 102 College Road, Harrow, Middle01
64W rms into
M -60
Number of channels: one.
Power output: 450W into 4 ohms, 300W into
8
ohms
and 150W into 15 ohms.
Distortion: less than 0.1% at rated power output.
Intermodulation: less than 0.1% at rated power
output.
Noise: 100 dB below rated power.
45.
4S2
one channel.
Nominal output impedance: 852.
Damping factor: 200.
Power bandwidth : 5 Hz to 30 kHz ±1 dB.
Protection : not specified.
Input impedance: 25 k52.
Gain : 0 dBm nominal for rated output.
Hum and noise: 106 dB below rated output.
Distortion : below 0.05% thd to rated output. Im
(SMPTE) better than 0.05% at all levels.
Other features: dV/dT 6V /us.
Rise time: 3µs.
Slew rate: 25V /us.
Sensitivity: 2V for rated
Dimensions (whd):
power output.
Power requirements: 117/240V ac.
Dimensions: 482
Weight: 27 kg.
Saxmundham,
Number of channels: two.
Power output: 30W rms both channels driven,
-427 2278/9.
Damping factor:
Estate,
D60
sex HA1 1BQ.
Phone:
Carlton Park Industrial
Suffolk IP17 2NL.
Phone: 0728-2262/2615.
x 170 x 345
D150A
mm.
P300
Number of channels: two
Power output: 150W rms, both channels driven,
200W rms into 452.
Nominal output impedance:
Damping factor: 20.
Power bandwidth : 20 Hz to
Number of channels: two.
Power output: 75W rms, both channels driven,
100W rms into 80 one channel.
Nominal ouput impedance: 852.
Damping factor: 200.
Power bandwidth : 5 Hz to 20 kHz ±1 dB at rated
output.
852.
20 kHz
48 x 4 x 20 cm.
Protection : not specified.
Other features : dV/dT 8V /us.
Power requirements: 120 to 260V ac.
Dimensions (whd): 48 x 17 x 24 cm.
M600
Number of channels: one.
Power output: 600W rms nominal, 1350W rms into
452.
Nominal output impedance: 851
Damping factor: 400.
Power bandwidth : dc to 20 kHz =1 dB
Protection : output sic not specified. Line over voltage and thermal protection provided.
Input impedance: 25 kO.
Gain : 20 dB.
Hum and noise:
below rated output.
0.05% thd and im (SMPTE)
120 dB
Distortion: better than
to rated power level.
BGW
3742, Beverly Hills,
California 90212, USA.
Phone: (213) 391 0320.
UK: Webland International Ltd, Mirabel House,
BGW Systems, PO Box
117/121
Wandsworth Bridge Road, London SW6.
Phone:
01
-736 0987.
The company's range includes a series of two channel amplifiers, the 2508, 500D and 750A, rated at 85,
200 and 300W (4 ohms) into 8 ohms both channels
driven. Prices are £415, £690 and £797. There are
two further models, 1000 and 1500, available to
±0.2 dB at
53
rated power.
Protection : unspecified.
Input impedance: 100 k53.
Gain : 1V for rated power output.
Hum and noise: 100 dB below rated output.
Distortion : less than
0.1 % thd and im (any level and
mixture between 20 Hz and 20 kHz) at rated output.
Other features: produces 'subtle nuances of inner
musical fabric which stir and warm the soul with
emotion'. Twin vu meters, power limiter control.
dV /dT 15V /us.
Connectors: 'Plenty of input /output terminals'.
Power requirements:
Dimensions (whd):
Weight:
100
to 240V ac. 500W.
445 x 152 x 355 mm.
25 kg.
Arncron
P250
Number of channels: two.
50
STUDIO SOUND, MARCH 1977
at rated
power.
D1 50A
The Amcron Story
1967
1977
1967 Amcron (Crown International) introduced the world's first 'Super -Amp'.
This was the
DC300! It rapidly became a must for all the major recording studios and top bands such as Zeppelin,
Jethro Tull and the Moody Blues.
In
The DC300 set new standards of sound reproduction never previously available for bands or studios,
let alone the Audiophile (whoever he is). Coupled with the incredibly rugged construction, and
small size of this 600 watts amplifier, it is not surprising that the DC300 became a legend in its time.
The designer of this classic is still in charge of the design work at AMCRON despite rumours that he
has moved on to at least five other establishments! Indeed, he has since been responsible for the
DC300A, the DI50A and all the rest of the AMCRON range of superb power amplifiers.
Now in 1977, the DC300A is `the' amplifier in all the world's recording studios and is still the only
choice for bands such as Zeppelin, Jethro Tull and the Moody Blues, plus quite a few others such as
Wings, the Stones, the Rollers, Elton John, 10c.c., Pink Floyd, Barclay James Harvest, The Real Thing
and so on
...
Perhaps this
is
because the DC300A amplifier offers the
following features:
* Harmonic distortion full power,
* distortion watt to watts into
*
better
watts
*
Bandwidth +1
-0 from to
*
warranty
*
Crown Protection Circuitry
circuit
*
to
into
low
* continuously for
Total
I
at
0.01
M
150
8
Hum and Noise
than 110db below
Power
db,
Full
3
year
db
ohms below 0.05%
150
20kHz at
DC
150
watts into
8
ohms
on parts and labour
Patented
Designed
Hz -20kHz below 0.05%
I
requires no
operate
load impedances
as
as
I
breakers or relays
ohm
Manufactured by a company founded in 1946 and represented by the MACINNES people
the last ten years!
MACINNES LABORATORIES LTD.
MACINNES HOUSE, CARLTON PARK INDUSTRIAL ESTATE,
SAXMUNDHAM, SUFFOLK IP17 2NL TEL: (0728) 2262 2615
MACINNES FRANCE S.A.R.L.
RUE FESSART,
PARIS 19e
Tel. 203.30.01
45
51
SURVEY: POWER AMPLIFIERS
Harrison Master Recording Consoles are
available through a selected number of
factory- trained professional audio distributors. Further information, assistance in
system design and service is available from:
AUSTRIA, SWITZERLAND
and EASTERN EUROPE:
Studer International AG
Althardstrasse 150
CH -8105 Regensdorf, Switzerland
Tel (01) 840 29 60 Telex 58489
special order. All models can be operated in the
bridged mode by rear panel switch. Power output
ratings are to the stringent FTC regulations.
All BGW amplifiers use crowbar protection circuitry; if the output current is exceeded, a thyristor
trips and discharges the power supply. The advantage of this arrangement is that reactive output
currents don't distort the output current, ie the output impedance remains low throughout the signal
voltage
cycle under
temporary
overcurrent
conditions.
BENELUX (BELGIUM, THE
NETHERLANDS and LUXEMBOURG):
Hegnen fi V
Steendalerstraat 5b
NL -6940 Gennep, Netherlands
Tel- (08851) 1956 Telex 48039
CANADA:
Strider Revox Canada Limited
14
Banigan Drive
Toronto, Ontario M4H 1E9 Canada
Tel (416) 42 -2811 Telex 06 -23310
DENMARK:
4
Quali-fi
A
-S
BOGEN
Bogen Division, Lear Siegler Inc, PO Box
Paramus, New Jersey 07652, USA.
Phone: (201) 343 5700.
TECHCRAFT
A range of transistor amplifiers with the output
coupled through a line matching transformer.
Strandvejen 730
DK -2930 Klampenborg, Denmark
Power outputs: 60/125/250W rms.
Number of channels: one.
Tel (01) 631711 Telex 16527
Output levels:
FAR EAST (Except japan):
Studer -Revox Hong Kong Limited
11)8 Asian House
1 Hennessy Road
Wanchai, Hong Kong B C C.
Tel 5- 278571. Telex 84640
FINLAND:
Into OY
Helsinki
11
Finland
Tel. (90) 171123. Telex 121836
FRANCE:
Studer France
12 -14, rue Desnouettes
17,
75015 Paris, France
Tel: 533 58 58 Telex 204744
GERMANY:
Noise: -100 dB.
Damping: 100 at kHz.
1
Sensitivity: 1.5V for rated power output.
Weight: 38 kg.
BOZAK
Bozak Inc, Box 1166, Darien, Conn 06820, USA.
Phone: (203) 838 6521.
Export agents: Elpa Marketing International Ltd,
Thorens Building, PO Box 1050, New Hyde Park,
NY 11040, USA.
Phone: (516) 746 3002.
CMA -1 -120
Number of channels: one.
Power output: 120W rms into 8 ohms.
Line: 70V.
Noise: 80 dB below rated output.
Frequency response: within dB 20 to 20 kHz.
Power bandwidth: within dB 30 to 15k Hz.
Frequency response:
220V ac standards.
Weight: 25 kg.
Price: $470.
dB 20 to 20k Hz at rated
output.
Noise: 86 dB below rated output.
Output regulation : better than
ohms
SMPTE method.
Distortion: less than 0.5% thd.
Protection: thermal.
Power requirements: can be supplied
1
4
1
to 120 or
dB from no load
to max.
CMA -1 -80
Protection : electrical, electronic and thermal.
Power requirement: 105/125V ac or - 24V dc.
Generally as above but 80W rms output. Price $417.
CMA -1 -50A
Generally as above but 50W rms output. Price $381.
Most amplifiers are available in two channel format.
TCB -S160
Number of channels: two.
Power output: 80W per channel into
8
ohms,
10 to
20k Hz.
Distortion: less than 0.05%
at rated output over the
quoted frequency range.
Voltage gain: 20 dB.
Intermodulation : less than 0.05% at any power to
rated output.
GREECE:
Weight:
lectronica O E.
Valaoritou Street
Athens 134, Greece
Tel: 3619096. Telex 214888
ITALY:
Audio Products International
Via Gaspare Spontini 3
20131 Milan, Italy
ohms,400W into
1
Franz Vertriebsgesellschaft mbH.
Elektronik, Mess- und Tonstudiotechnik (EMT)
Postfach 1520
D -763 Lahr 1, West Germany
Tel (07825) 512. Telex 754319
13.7 kg.
E
9,
8
per channel, both channels driven.
Distortion : less than 0.25% thd at 250W.
Intermodulation: less than 0.15% at 250W by
25, 50 or 70V line balanced or
unbalanced. 16V direct, unbalanced.
Input sensitivity : 250 mV for rated output.
1
Mentullinkatu
500,
Power output:250W into
The company also manufactures a range of power
amplifiers intended for public address. These
incorporate integral preamplifiers.
DUKANE
Dukane Corporation, International Division,
2900 Dukane Drive, St Charles, Ill 60174, USA.
Phone: (312) 584 2300.
The company manufactures a range of public
address amplifiers which feature 25, 50 and 70V
output lines.
1A921B
200W rms.
1A911B
100W rms.
1A901B
50W rms.
Tel (02) 27 38 96. Telex 32402
JAPAN:
Shindenshi Manufacturing Corp.
1 -47 Sasazuka, Shibuya -Ku
Tokyo, japan
Distortion:
1.5 °u
thd at rated output.
Frequency response: 20 to 20k Hz _
Noise: 80 dB below rated output.
Input sensitivity : 0.4V, -6 dB.
Output regulation: better than dB,
Tel 03- 460 -6052
MEXICO:
Ingenieros en E lec tronica Asociados S.A. de C.V.
Alpes 1221
Lomas de Chapultepec
Apdo. Postal 41660
Mexico 10 DF
Tel. 5- 20- 91 -34. Telex 1775756
SPAIN:
Neotecnica, s a e.
Marques de Urquijo, 44
Madrid 8, Spain
Tel 242 -0900 Telex 22099
1
1
dB.
0
to full load.
DUNLAP -CLARKE
See review p80
SWEDEN:
FIFA Radio & Television AB
Industrivaegen 23
S -171 17 Solna, Sweden
Tel (08) 730 07 00 Telex 104 79
UNITED KINGDOM:
Scenic Sounds Equipment
27 -31 Bryanston Street
London W1H 7AB, England
Tel: (011935-0141. Telex 27939
EXPORT AGENT:
Audio Systems International
146 North Orange Drive
Los Angeles, California 90036
Tel: (213) 933 -2210. Telex 698645
FACTORY:
Harrison Systems, Inc
Post
Office
Box 22964
Nashville, Tennessee 37202
Tel. (615) 834 -1184 Telex 555133
Bose 1801 dual- channel power amplifier
EPICURE
BOSE
Bose Corporation, 103 The Mountain
Framingham, Mass 01701, USA.
Phone: (617)
Road,
879 7330.
UK: Bose (UK) Ltd, Sittingbourne Industrial Park,
Crown Quay Lane, Sittingbourne, Kent.
Phone: 0795 -75341.
1801
Number of channels: two.
Epicure Products Inc, 1 Charles Street, Newburyport, Mass 01950, USA.
Phone: (617) 4623181.
EPICURE ONE
Number of channels: two.
Power output: 125W rms per channel, both channels driven between any frequency 20 to 20k Hz into
8
ohms.
Total harmonic distortion: less than
0.2 %.
54
53
SURVEY: POWER AMPLIFIERS
Intermodulation distortion: typically below 0.03 %.
Power bandwidth: 10 to 52k Hz.
Rise time:
1.5 us.
Damping factor: greater than 100.
Slewing rate: 17V /ps.
Noise: better than 100 dB below full output.
Phase response: less than 15° from 20 to 20k
Protection: thermal, short
Weight: 26.4 kg.
GALACTRON
Hi -Fi Galactron International,
Negroni,
00040
Hz.
Galactron
MK 160 stereo/
quadraphonic amplifier
and line.
18
Via Quarto
Ariccia (Cecchina), Italy.
UK:
Ltd,
Loudspeakers
Goodmands
Hampshire.
Phone: 070 12 -6344.
Havant,
M Kl60
Number of channels: four.
Power output: 100W /channel, all four channels
driven.
Load impedance:
8
ohms.
Distortion: less than 0.2 %.
Intermodulation: less than 0.2 %.
Input sensitivity: 0.7V for rated output
Weight: 18.2 kg.
Size: 48.3 x 8.9 x
TPA
on each
channel, 1.4V in stereo bridging position.
Power requirements: 115/230V ac 560W.
Dimensions: 462 x
Price :$1059, £660.
Cooling : forced air.
235 x 310 mm.
HEIL SOUND
Heil Sound Manufacturing, Heil Industrial Blvd,
25D
Number of channels: one.
Power output: 30/65/70W into 15/7.5/4 ohms.
from 20 to 20k Hz at load
less than 0.1
impedances between 7.5 and 15 ohms.
Frequency response: within 0.4 dB over the audio
range.
Input: 0 dB nominal.
Noise: 100 dB below rated output.
Damping factor: greater than 100 depending on
load.
Slew rate: 1OV/ps.
TPA
50D
The company manufactures a range of three amplifiers with similar electrical performance differing
only in power and price:
TPA
100D
As above except 60/80/100W power output.
OHMEGA 100/2001400
Power output: 75/150/250W per channel, both
ohm load.
Frequency response: 20 to 20k Hz +1 dB.
Distortion: 0.1% at rated output at kHz.
Noise: better than 95 dB.
Input level: 0 dB across 10k ohm bridging.
The manufacturer states that the amplifiers use
modular construction enabling very quick plug in
repairs to units in the field should this be necessary.
A repair kit is produced for this purpose.
James B Lansing Sound Inc, 3249 Casitas
Avenue, Los Angeles, Ca 90039, USA.
Phone:
C E Hammond and Company Ltd, 105/109
Oyster Lane, Byfleet, Surrey KT14 7LA.
Phone: Byfleet 41131.
UK:
Distortion:
Marissa, III 62257, USA.
Phone: (618) 295 3000.
channels driven into
38.6 cm.
JBL
As above except 100/180/250W power output.
Distortion: less than 0.2 "0.
Frequency response: within 0.5 dB over the audio
range.
6233
Number of channels: two.
Power output: 200W /channel into
8 ohms, 300W/
ohms; both channels driven.
Power bandwidth : 20 to 20k Hz ±0.5 dB all power
levels to rated output.
Distortion: less than 0.05% thd, both channels
driven at rated output.
Intermodulation: SMPTE method less than 0.05 %.
Rise time: 4 us or less.
Slew rate: greater than 20V /ps.
Damping factor: 40 minimum.
Noise: 100 dB below rated output.
channel into
4
Input sensitivity: 0 dBm.
Connectors: Cannons.
Power requirements: 120/240V ac.
Special features: uses a 2 kW switching invertor
power supply.
Dimensions: 13.3
Weight: 15.7 kg.
4
x
48.3 x 46.5 cm.
1
H/H Electronic S500D
MARANTZ
Marantz Inc, PO Box
91352,
99,
Sun Valley, California
USA.
UK Ltd, Debmarc House, 203 London
Road, Staines, Middlesex.
UK: Audio
H/H
H/H Electronic, Viking Way, Bar Hill, Cambridge CB3 8EL.
Phone: 0954- 81140.
Phone: Staines 50132.
56
$500 -D
Number of channels: two.
Power output: 340W/4 ohms, 210W/8 ohms,
110W/16 ohms one channel driven.
Bridge power output: 900W/5 ohms, 640W/8 ohms,
400W/16 ohms. All above power outputs are measured at clip point without any reference to distortion
performance at the specific load impedances.
Distortion : less than 0.02% 10 to 10k Hz 'at all levels
up to clip point'.
Intermodulation distortion: less than 0.02% from
0.1W to 200W into 8 ohms by SMPTE.
Frequency response: within 0.2 dB dc to 20k Hz,
dc coupled.
Slew rate: 10V /us.
Rise time: 10µs.
Noise: 105 dB below 180W into 8 ohms.
Damping factor: greater than 300.
Input:
54
0
dBm nominal.
STUDIO SOUND, MARCH
1977
Millbank
PAC -System
amplifier
with
front loading
inputs
removed
The StuderA68
Amplifier
a powerful ..break
-
-
The Studer A68 is a unique break-through in
high power amplification for professional use.
Ins 100 watt per channel (into 8 olnns ) power
capability is achieved through corn pletely new
design concepts which have eliminated transient
intermodulation distortion while keeping
harmonic distortion below 0.1% at all power
levels. The result is a fully professional low
distortion amplifier ideally suited to continuous
high power operation under arduous studio
conditions.
Other features of the Studer A68 include:
100W stereo or 350W mono (into 8 ohms)
Fully electronic protection circuitry
Q Low overall feedback for very low distortion
C Complementary push-pull circu.tsthroughout
Standard l9-inc::, rack mounL:mg size
High efficiency power stppl y amply -ated for
continuous high power operation
Level controls for each channel on the front
panel
F.WQ Bauch Limited
49 Theobald Street, Boreharn Wcod
Hertfordshire .WD6 4RZ
Tel 01953 0091 Telex :27502
,
:
STEREO POWER AMPLIFIER
A68
POWER CR
STUDER
OPE
RIVEL
O1NLOA0
WRIST
tN/WNEL
SURVEY: POWER AMPLIFIERS
The company manufactures a range of rather con sumerorientated power ampl fiers ranging from 75 to
250W /channel. Typical distortion levels are quoted
as less than 0.1 g thd from 20 to 20k Hz. Price range
from £260 to £950.
Mustang
SS50 power
amplifier
MILLBANK
Millbank Electronics
Sussex TN22 IPS.
Phone: (0825) 4166.
Group
Ltd,
Uckfield,
PAC -SYSTEM
Available with power ratings of 30, 50 and 100W,
each with a six input capability. A range of over 30
pre -amplifiers, am /fm tuners and combiners, which
front load into the main PAC -System amplifier allow
for the requirements of any potential sound installation to be provided for.
Noise: 100 dB below rated power output.
Voltage gain: 34 dB.
Protection: electronic current limiting.
PA I
Number of channels: two.
Power output: 75W /channel, both channels driven
Weight: 6
Options:
into
kg.
can
supplied with line matching
be
ohms.
and £70.
Sensitivity:
MUSTANG
NAIM
SS700 and SS50
USA: Audiophile Systems,
15
ohms. 150W and 80W into 7.5 ohms.
Power bandwidth: within 0.5 dB 10 to 20k Hz into
15 ohms.
Distortion: less than 0.5% in the power spectrum;
typically below 0.1
at kHz.
Sensitivity: 0 dBm for rated power.
1
1.5V for rated power output.
Price: $600,£350.
Mustang Communications, Nelson Street,
Scarborough, North Yorkshire Y012 7SZ.
Phone : 0723- 63298.
Number of channels: one.
Power output: 100W and 50W nominal into
68 kHz.
Slew rate: 8V /ps.
Damping factor: 67.
Noise: better than -95 dB.
Distortion: less than 0.2% thd.
transformer.
Price: £94
8
Power bandwidth :
NAIM Audio Ltd,
Wiltshire SPi 1DT.
Phone: (0722) 3746.
11
Salt Lane, Salisbury,
Quintessence PA II
5750 Rymarck
Court,
Indianapolis 46250.
Phone: (317) 849 7130.
Agents in Australia, Holland, Israel Japan, Scotland
and Singapore.
,
NAP 120/160/250
Number of channels: two.
Power output: 40W /50W /70W per channel into
8
ohms, both channels driven.
Distortion (NAP160):less than 0.03 ", intermodulation distortion products at 35W.
Output offset: less than 40 mV.
Input sensitivity for rated output: between
0
and
6dB.
Protection: will tolerate
infinity without damage ...
Price: troni around £140.
any load from zero to
'
QUINTOR
Quintor Electronics Ltd, 57 Shortwood Avenue,
Staines, Middlesex TW18 4JN.
Phone: Staines 56935.
Twin 100
Number of channels: two.
Power output: 100W /channel into 8 ohms.
Load impedance: not less than 4 ohms.
Nairn NAP 120
Input:
1V rms.
Frequency response:
THE FOURTH COURSE
FOR STUDIO ENGINEERS
WILL
Distortion: less than
Noise: better than 75
BE
SEPTEMBER
dB at rated
:1
thd at 1 kHz.
dB below rated output.
0.1
RAC
Rugby Automation Consultants,
Road, Bilton, Rugby CV227HZ.
Phone: 0788 -810877.
17 -23 1977
PREVIOUS COURSES
OVERSUBSCRIBED
QUINTESSENCE GROUP
Quintessence Group, Audioworks Division,
1115 'E' Street, Sacramento, Ca 95814, USA.
Phone: (916) 441 5175.
Details from
PA II
Number of channels: two.
Power output:150W /channel, both channels driven
APRS SECRETARYE L MASEK
23 Chestnut Avenue,
Chorleywood, Herts, UK
into
STUDIO SOUND, MARCH
8
ohms.
Power bandwidth
Slew rate : 5V /ps.
:
74 kHz.
Distortion: less than 0.2% thd.
Noise: better than -95 dB.
Damping factor: 107.
Sensitivity :0 dBm.
Price: $1300, £760.
WD3 4HA
56
20 to 20k Hz
power.
1977
19
Freemantle
RACAMP 50 and RACAMP 100
Number of channels: one.
Power output: 50/100W rms.
Nominal output impedance: 8/40..
dB.
Power bandwidth: 10 Hz to 20 kHz
Protection not very clear; some protection of
1
:
unknown nature provided.
Input impedance: 90 kSi.
Gain: 420 mV for rated output.
Hum and noise: 76 dB below 50 mW.
Distortion: 0.025% thd at kHz, 0.15% at
1
power level unspecified. Im
(unstated level and mixture).
Power requirements: 240V ac.
Dimensions (whd): 135 x 133 x
less
12.5 kHz,
than 0.25%
254 mm.
Price: £65/£72.
A 50 1-50W /channel dual Racamp
price £88.
50 is
available,
58
BGW PRIME
BGW
is
about to whet your appetite with their new Model
The Model ioo will drive the most
difficult loads you can throw at it. Electrostatic headphones and reactive speakers are
driven flawlessly due to the loo's unique
design. No form of current-limiting is used
whatsoever. A precision monitor amp
for any application , the modular construction of the ioo means one integrated amplifier
circuit board with the biggest heat -sink we
could package in 1-3/4" of vertical rack space:
340 square inches of efficient sink. No more
ioo Stereo
Power Amp,
On the inputs, you can get optional
Cannon XLR's and plug -in transformers ...and
into 8 ohms you get 33 watts per channel, or
8o watts mono. Into 4 you get a meaty 44.
The I M distortion is an incredibly low .off.
It's about time somebody like BGW
would mete with the competition. Check
out the Model ioo. It's just one of six
professional prime cuts... of course, all above
the rest.
thermal shutdowns.
There's a sophisticated "loss of- feedback" circuit with front
panel L.E.D's. Also unique
to the ioo, the L.E.D's are
driven by a one -shot
circuit for precise
clipping indication.
Instantaneous peaks, which
get by most amps, are stretched out in our
L.E.D, circuit so you can see them.
SYSTEMS
BGW Systems isi3o South Yukon Ave., Hawthorne, Ca 90250 (n ;) 973 -8090
In Canada: Omnimcdia Corp., ro24SCote de Líesc. Dorval Quebec H9P IA; lss.) 636.9971
Worldwide Export Agents: Telesco International Corp., One Dupont Street South.
Plainview. L.I., New York,
(516)
433.6no
57
SURVEY: POWER AMPLIFIERS
RADFORD
Radford Audio Ltd, Ashton Vale Road, Bristol
BS3 2HZ, Avon.
Phone: 0272- 662301.
ZD 200/100/50
Power output: 150/90/70W per channel into 8 ohms;
250/150/110W per channel into
4
ohms both channels
driven.
Distortion: less than 0.004% thd
at
1
kHz, rated
power 8 ohms.
Noise: 110 dB below rated output.
Sensitivity: 1V for full output.
Intermodulation; less than 0.01% by SMPTE.
Weight:
16 /13/11 kg.
Radford ZD
100
SAE
Scientific Audio Electronics Inc,
Street, Los Angeles, Ca
Phone: 1- 213- 489 -7600.
90012,
701
E
Macy
USA.
2400L
Number of channels: two.
Power output:200W /channel both channels driven.
Distortion:
less than 0.05% thd and im.
Noise: 100 dB below rated output.
Slew rate: 40V/us.
Price:
$800
SAE 2400L stereo power amplifier
Power
Studer International AG, Althardstrasse 150,
CH -8105 Regensdorf, Switzerland.
Phone : 01 840 29 60.
US: Willi Studer America Inc, 1819 Broadway,
driven.
Nashville, Tenn 37203.
UK: FWO Bauch Ltd, 49 Theobald Street, Borehamwood, Herts WD6 4RZ.
Phone: 01 -953 0091.
Damping : in excess of 30.
Noise: greater than 90 dB.
Frequency response: within
A68 (see review
Protection: current limiting electronic and fuse.
Price: £96.
p 68)
Power output: 100W /channel into 8 ohms, 175W/
channel into 4 ohms both channels driven. Bridge
connected 400W into 8 ohms mono.
Frequency response: within 1 dB from 20 to 20k Hz.
Distortion: less than 0.1 % at rated power.
Noise: better than 100 dB.
Damping factor: better than 75.
Weight: 20 kg.
Protection: electronic, crowbar
and thermal and
dc offset.
Price: £528.
A740
A Revox consumer version of the A68. This un it has
unbalanced inputs, headphone outputs, etc. It
features two front panel signal meters.
nated types BÁ5000 and 8A6000.
E Sugden & Co Ltd, Carr Street, Cleckheaton,
West Yorkshire BD19 5LA.
Phone: 0274 -872501.
USA and Canada: Reference Audio Ltd, 1885
J
Darling Suite 201, Montreal, Quebec.
Singapore: Atlas Sound Co, b.1/3 U.I.C. Building,
5
Shenton Way, Singapore.
Australia: McGlew
Adelaide, South
SPECTRA SONICS
Spectra Sonics, 770 Wall Avenue, Ogden,
Utah 84404, USA.
Phone: (801) 3927531.
50W /channel,
both
channels
Nominal load impedance:
8
Distortion: less than 0.05%
Voltage gain: 32 dB.
at rated power output.
ohms.
.75 dB between 30 and
20k Hz.
Rise time:
7
us.
SWTP
South West Technical Products Corporation,
219 West Rhapsody, San Antonio, Texas 78216,
USA.
TIGERSAURUS 250
Number of channels: one.
Power output: 250W into
4
ohms; 200W into
Distortion : better than 0.1'7 at above power levels.
Intermodulation distortion: less than 0.03 %;
,
& Co Pty Ltd, 34
Australia 5001.
P51
Power bandwidth:
20 to 20k Hz.
TIGER 207
Number of channels: one.
Power output: 60W into either 4 or 8 ohms with
less than 0.05% total harmonic distortion from 20 to
20k Hz.
Pirie Street,
Intermodulation distortion : less than 0.01%.
Noise: less than -90 dB.
Damping factor: over 100.
Input: 1V rms.
Number of channels: two.
60
700
a printed circuit card comprising one of an
array of power amplifiers fitting within a 48 cm rack.
Number of channels: up to eight within one rack.
Power output: 60W developed across 4 ohms;
modules may be bridge connected to double individual ratings.
Power bandwidth: within 0.3 dB at rated output
(4 ohms) dc to 20 kHz.
Total harmonic distortion: less than 0.01'' at full
This is
output.
Intermodulation: less than 0.1 at full output.
Gain: 21.2 dB.
Signal -to -noise ratio: better than 100 dB below
full output, 20 to 20k Hz.
Slew rate:10V/us.
Input impedance: 10k ohms.
Phase shift: less than 5:.
Power requirements: 30V dc maximum.
Price: $84 per module.
58
STUDIO SOUND, MARCH 1977
:
8
ohms.
measurement method unspecified.
Damping factor: over 100.
Noise: better than -95 dB.
Input level: 2V rms.
SUGDEN
SANSUI
The company manufactures two large power amplifiers rated at 300W /channel and 170W /channel into
8 ohms. Distortion figures are quoted as less than
0.1
and 0.05 thd respectively. These are desig-
output:
STUDER/REVOX
Sugden
P51
power
amplifier
0-
50000 Miles
Farts & Labor.
/ivv,v
irr, '/ia thifir,
1/..e.41 if r
Tear us apart, Modularly.
We think we're realistic. Despite the
rugged and proven design of our amps, we're
not perfect. Sometimes they need attention like
anybody else's.
This ad is
not about
performance. We know you've
accepted us as the company
with the most to offer, .more
studios and music people seem
to be making The Big Decision
to switch their power amplifier
needs to us.
Setting our
better performance
,
aside, a big
difference between
us and the others is our
ease of servicing. Although our three year parts
and labor warranty is not unique, our modular
design that allows rapid and easy component
changeout is. After the 5o,000 miles on the road
'/
or the equivalent run of tape in the studio, we
survive longer because you can keep us around
without
a lot of hassles.
A BGW amp is a practical, austere looking
piece of gear for good reason. In an environment
where only the strong survive, you'll be seeing
more austere BGW
front panels. 50,000
miles later, if the
parts and labor are
needed, tear us
apart, modularly.
Get our
information on a full
line of power amps
and find out why
more roadies are
lugging our heavy
amps and studio
engineers love us.
tp ;o South Yukon Ave., Hawthorne, G grogo
9738090. In Canada: Omn1media Corp.,so245Cote de Liesse,
Dorval, Quebec H9P IA; (52q) 636 -qqn. Worldwide Export Agents:
BGW Systems
213)
SYSTEMS
Te1óco International Corp., Onc Dupont Street South, Plainview, L,I.,
New York, (516) 433ó21
59
SURVEY: POWER AMPLIFIERS
TELEMATION
TeleMation, PO Box
Utah 84115, USA.
Phone: (801) 972 8000.
UK:
293 Regent Street,
01 -636 9447.
15068,
Salt Lake City,
London W1V 2HR.
Phone:
T M A525
This is a modular amplifier for building into consoles
and equipment racks. Using balanced 0 dBm line, it
produces a maximum of 10W into 8 ohms. The company can provide special racks and power supplies
for powering up to six units. Voltage requirements
+18V dc.
Price:
TURNER
Turner Electronic Industries,
London W7 3TH.
Phone
:
175
Uxbridge Road,
Number of channels: two.
Power output: 150W /channel into
Size: 483 x 134 x 302 mm.
Price: £395. With vu meters
4
ohms, 100W/
ohms, 60W/15 ohms.
Power output (bridge connection): 300W/8 ohms.
Frequency response: within 0.2 dB over the audio
range.
Noise:
110 dB
Output impedance: 0.01 ohms from 20 to 400 Hz.
Inputs : +4 dBm.
Distortion : less than 0.01",;, at rated output into any
quoted load condition.
Protection : quite a lot of it.
Weight: 13.5 kg approx.
01- 567 8472.
A300
8
Turner A300 professional stereo amplifier
$315, £189.
below rated output.
YAMAHA
Natural Sound System, Strathcona
North Wembley, Middlesex.
Phone 01-904 0141.
Road,
:
P2200
Dynamic power: 600W + 600W into
£485.
The company also manufactures amplifiers with
other power ratings with (one imagines) similar
performance specifications to the above. These are
a 250W /channel A500 at £550 without vu meters and
a 100W /channel unit for which no price is yet
announced.
1
4
ohms at
kHz, the of 0.1%.
5 Hz to 100 kHz +0 -1.5 dB.
Standard 48.3 cm rack mounting- equipped with
feet for free standing. Equipped with peak programme meter and attenuators.
Price: £492 inc VAT.
Frequency response:
Dunlap Clarke Electronics
BROUGHT TO YOU
BY
To the readers of STUDIO SOUND.
As you know, we have been working with DUNLAP CLARKE
in producing a range of Amplifiers and PRE -AMPLIFIERS that
sound musical, have good reliability, are rugged, easily serviced,
are reasonably priced, that we can sell in Europe.
DUNLAP
Now we can say,
have the
"we are truly happy with our range ". We
CLARKE DREADNOUGHT
DUNLAP CLARKE DREADNOUGHT
DUNLAP CLARKE DREADNOUGHT
1000
500
250
A PRE -AMPLIFIER-the MIO.
We believe that this list is truly
a comprehensive range of
amplifiers, from 500w per channel. All amplifiers are designed to
work into low impedance loads (2ohms).
For professional use there are three amplifiers in the range
that will work exceedingly well.
For P/A use, the 250 and 500 models are ideally suited.
Dunlap Clarke DREADNOUGHT 1000 Audio Power Amplifier
19
ALL the amplifiers are suited for ALL audio uses, but through
experience we have found that the latter models will work
satisfactory, in all cases.
RICHARDSON ROAD, HOVE, SUSSEX
Tel: 0273 -777915 in business hours IOam -5pm MON -FRI.
60
STUDIO SOUND, MARCH
1977
Photograph courtesy
yyyyyy»yJpÿs3íxá'«'3ct
ÿyyyywy¡aa
.rT TT.
CBS Studios, London.
_}AT'1"T!#`i'YG
''?4-1#1
t''1
fi
T
14t
T
'T1
1`i'1;1`1`1
500 SERIES
We are Businessmen who happen
to be recording equipment designers.
If you run a recording studio and happen
to be Businessmen also, then you will
be using MCI equipment.
Turning studios into profitable
concerns is a rewarding experience.
It's also good business.
Not for nothing is MCI's JH-500 called
THE BUSINESS MACHINE.
\tit\t\
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London NW1 3EX.TeI:OI -388 7867/8.Tx: 261116.
iuok
Sun Studio /Thames Valley
Broadcasting
Reading, as any statistician will
tell you, is the most nationally
average place in England. Accepting the challenge, 1 took a trip to
Reading to see what kind of studio
enterprises 1 could find to report.
a £1000' deal, whereby a group, for
instance touring the northern clubs,
can come into the studio, record
an Ip and have it mixed, cut, and
a thousand copies pressed and
packed into attractive printed
sleeves for the total of £l each.
These can then be sold by the band
at gigs, for around £2 a time, with
everyone happy over the deal.
Indeed, some of the northern clubs
are now heavily geared to this kind
of promo album exercise. They
have special stalls set up in the
lobby, and take a percentage cut
of the profits from record sales
during the gig. This is how the
Vaudeville Band came to record at
Sun and the results are commendable for the low price.
The equipment in the control
room is an Otani 8- track, which
cost Sun around £4000 and over
which they have no regrets. Only
problems so far are an unhappiness
of the machine with matt- backed
tape, which leaves the tension idler
running in the wrong direction
after tape direction has been
switched. There is also no counter,
which seems a curious omission.
Mastering is on Revox A77 and
A700, the desk being a heavily
Allen
and
Heath.
modified
Amongst the future plans is a new,
custom -built console designed by
Maynard, an engineer with a Post
Office background. But again,
surely it would have made more
sense to ask us along after the new
desk was installed?
The demo business is partly
bread -and -butter, partly a night-
Sun Recording Services, of
Crown Street, Reading, had made
the point to us in a letter that
although the area of Berks and
Bucks around Reading is knee deep in private recording studios,
owned and used by the many
musicians and pop stars who have
retreated to the area, Sun is just
about the only local commercial
multitrack studio open to the public. It is a small studio, so far
specialising mainly in commercials,
cassette duplication and the demo
market. But some reasonable names
(such as the New Vaudeville Band)
have recorded there. And last year
Van Morrison, who lives along the
river Thames, brought in the likes
of Keith Tippett and Vinegar Joe
and spent a couple of weeks
rehearsing at Sun before moving
farther upstream to record at the
Manor near Oxford. It is doubtless
this, and an obviously busy time
with commercials for the local
radio station (of which more
later), which has given Sun the
cash and confidence to plan a major
restructure of the terraced house
in which the studio is located. The
office will be turned into control
room, wall knocked down, relax
rooms fitted out upstairs, and so
on. But for the benefit of other
small studios interested in a visit
from STUDIO SOUND and a write -up
in these pages, it would make more
sense to invite and open the doors
to the press after such a major
restructure, rather than before. Be
that as it may, we did visit Sun, and
found the current situation worth
a report, albeit mainly on the
strength of the very acceptable
sound the studio gets from what is,
frankly, so far an economy setup.
Also, as director and working
engineer, Martin Maynard, points
out, the studio relies for its bread
and butter on a busy field which
we have tended to neglect -the
demo market. For this, Sun charges
pretty much rock bottom rates-£8
an hour or £80 for a 14 -hour day.
Also offered is a `thousand Ips for
STUDIO SOUND, MARCH 1977
62
mare, and partly a pleasure. Like
any demo studio, Sun get in some
appalling no -hope talent who know
nothing about recording and even
less about music. As one `manager'
for a young lady singer whom he
was `sponsoring' said, when he
brought her in to record a demo,
`the young lady's got a very loud
voice, so you won't need a microphone'.
As Maynard points out, he and
his obviously talented musical
partner, Rob Boughton, are able
to involve themselves in the business of producing a demo far more
than the staff of a comparable
studio in London with heavier
overheads. `We don't start charging
the moment they come through
the door,' says Maynard, `and we
don't pull the plug the moment
the money runs out.' On the other
hand Sun have found it necessary
to explain a few facts of life to
some groups, like, for instance, the
fact that studio time isn't charged
only while the tape is running.
When a group is prepared to listen
to advice and let itself be produced,
Boughton and Maynard are willing
to advise and produce. It's easy to
forget how totally foreign the whole
business of modern music recording
is, even to reasonably competent
groups who are accustomed only
to playing live gigs. One local
group, for instance, tried to engineer its own fades by playing quieter
and quieter towards the end of
each take. The engineer was pushing up the faders in desperation,
until he finally realised what was
happening.
Some groups, although musically talented, have no knowledge
of overdubbing and the kind of
special effects that even a relatively
simple studio setup like Sun can
produce.
I heard one tape, of a group
called Gambler, from Swindon,
who had listened to Sun's suggestions. As a result four tracks had
been produced in one day's record-
ing and a night's mixing, with up
to 20 vocals overdubbed by judicious bump- tracking. Especially
bearing in mind that the studio as
yet has no Dolby or dbx, which
makes noise a potential problem,
the results are good. And the group
just has to be a winner -both
group and sound decidedly are
above the national average, one
might say.
It struck me, while staying at
the average Reading Post House,
that the new ilr stations are fighting something of an uphill battle.
Each hotel room had a bedside
loudspeaker piped with a choice of
four programmes of sound. There
was Radio 2, 3 and 4, and a `music'
channel of pre- recorded wallpaper.
But just down the road from the
hotel is the transmitter for Thames
Valley Broadcasting, and I could
only hear its programmes because,
like a wise virgin, I had taken my
portable trannie with me. Even the
local Evening Post newspaper doesn't exactly fly the Thames Valley
flag. While listing Radios 1, 2, 3
and 4 and BBC Radio Oxford
(which in any case shares many of
its programmes with Radio 2) in
detail, the local commercial programmes were condensed to literally
seven words for one day and 14
words the next, including times!
In fact, the paper even gets the
station name wrong. The correct
title for the Reading ilr station is
Thames Valley Broadcasting, not
the Radio Thames Valley tag used
by the local newspaper. Probably
this is something of a hangover
from some brisk, bitter wheeling
and dealing which put Thames
Valley Broadcasting (under programme controller Neil St. J.
ffrench -Blake backed by Rupert
Murdoch's `News International')
on the air rather than the rival
Thames Valley Radio Company
which had been engaged in heavy
local promotions and right up to
the last moment looked likely to
get the contract. Be all that as it
may, TVB was the eighteenth, or
last- but -one, ilr station to go on
the air. And it did so with a launching capital of only £220 000.
According to ffrench- Blake, and he
is happy to be quoted on the point,
the station still has money in the
bank and has made a trading profit
every month since opening. Certainly locals seem to like the
station, feeling it is giving average
Reading a sense of identity, and
the programming is some of the
most interesting and adventurous
that I have yet heard on a local
station.
First and
foremost point
of interest is the station policy over
phone -ins and dedications. In a
64
www.americanradiohistory.com
0
-TURNER-
AUDIO DEVELOPMENTS
Hall Lane, Walsall Wood, West Midlands
WS9 9AU
PROFESSIONAL STEREO POWER
AMPLIFIERS
Phone 05433 -5351
SPECIALISTS IN PROFESSIONAL PORTABLE
MIXING
Model A500 provides 180 watts per channel into 8
ohms (280 watts per channel into 4 ohms) and is
recommended for use in the most demanding studio
monitoring or p.a. situation.
f er
reo ÿbwerm
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ova
yludvJI i(ar
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Model A300 -the studio standard -provides 100 watts
per channel into 8 ohms (150 watts per channel into
4 ohms). As supplied to leading recording studios.
Principal Products:
AD007 MINI Mixer
8/4 battery- powered (with external power option). Modular construction for ease of servicing, MIC or LINE inputs, comprehensive EQ,
line up Oscillator, two switched meters and compressor /limiters.
Many options including provision for increasing number of inputs to
20 using external unit connected via Extender Socket.
AD03I
MICRO Mixer
8/2. I. Generally as AD007 but smaller. Two main groups remixed
to give a third -stereo and mono operation at same time. Oscillator
compressors, etc are optional extras with AD031 and many others
available (including extension).
AD045
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6/2 powered by rechargeable battery, XLR or DIN versions available.
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Technical literature
Retains most of features of AD007 and ADO3I but each module can be
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available:-
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LIST OF AGENTS
M. R.
Drott,
Johannesgasse 18,
A-1015 Wien,
AUSTRIA
Studio Centre,
3
Rue Du Telegraphe
75020 Paris,
FRANCE
Dr W. A. Gunther,
Ingenieurburo SIA,
8702 Zollikon, Zurich,
Seestrasse 49 -51,
Laboacustica,
Via Muggia 33,
00195 Roma,
Tel: 3595506/386867
ITALY
Sound Techniques,
Postbus 206,
Almaar,
HOLLAND
Phillips Electronic
Industries Limited,
200 Consumers Road,
Suite 105,
Willowdale, Ontario,
CANADA
A300 specifications
A500 reviewed
A300 reviewed
Sly Ing Benum & Co,
Boks 2493,
Solli, Oslo 2,
NORWAY
Turner Electronic Ind. Ltd.
175
Uxbridge Road, London W7 3TH.
SWITZERLAND
01
-567 8472
63
WORK
word, there aren't any. As DJ,
Tony Fox, says, `dedications mean
a lot to the one person involved
but nothing to anyone else.' The
nearest the station gets to dedication is allowing Sam from Basingstoke to phone in and say 'Hullo,
I'm Sam from Basingstoke', and
then partake of a quiz or the like.
There's method in this, because it
gives a remarkably good dipstick
of how and where the station is
being received.
The station building is in a converted CD fire engine shed several
miles out of the town centre. It's
thus modern and virtually custom built with room for expansion.
Controller ffrench-Blake and colleagues originally planned it out
using Lego, and the offices off the
studios are on two -level open plan.
'My god,' said a retired Air Force
officer who visited the station, 'it's
like an old Battle of Britain ops
room'. At this ffrench -Blake, who
sits upstairs in the ops room,
immediately had visions of girls
downstairs pushing top 40 discs
round a table with long sticks. In
fact a more common sight, with
the studios out of town in somewhat rustic surroundings, is a longhaired dog, waiting while its master
makes a broadcast.
To complement the somewhat
odd situation of studios out of
town, the transmitting aerials are
fairly central in Reading. The vhf
fm stereo transmissions (0.5 kW
erp) seem to carry round the designated area reasonably well, but
the medium wave output, with
only a measly 100 watts erp) is a
real source of concern. The 210
mw frequency is shared with a high
power Russian station, and of
course almost shared by a certain
208 putting out a megawatt in
Luxembourg. So, at night, TVB on
the medium wave virtually falls
off the end of the transmitter. It
seems that Reading was the first
ilr station to come on the air
after the recent conventions
which clamped down on transmitter powers, and thus there is no
chance of an upgrading. ffrench Blake has realistic attitudes to the
problems of poor night time reception on medium wave. 'We've got
to get people into vhf, but it takes
time we're still Radio 210, not
Radio 97.'
The staff also seem generally and
understandably irked that BBC
Radio Oxford, with 17 kilowatts,
conies in decidedly loud and clear.
And even Capital encroaches on
Reading territory. Without doubt
there would be enthusiasm for
anything, be it Dolby or whatever, that could push up TVB's
-
effective power.
.64
Floyd studio
It is currently fashionable to report
in sensational manner on the casualties of Flower Power, Underground Music and the Heavy Rock
Sound scene of a few years ago.
So it's a safe bet that the popular
papers won't quote from the following report on a new studio in
It's
Britannia Row, Islington.
operated by Pink Floyd, four
musicians who represent anything
but casualties of that era.
first saw and heard Floyd in the
original UFO Club, literally under
Tottenham Court Road, just about
a decade ago. After several years
with the 'underground' tag, they
became major EMI recording
artists, and hit the jackpot with the
Dark Side of the Moon 1p, recorded
at Abbey Road between June 1972
and January 1973. Engineered by
Alan Parsons, the album soon
became a best seller, and deservedly
so. The only mystery is in why it
should continue to sell in what
appear to be unabated quantities,
though one possible explanation
is the quadraphonic remix by Alan
Parsons, for an SQ release by
EMI. There was a time, a couple
of years ago, when every quadraphonic demonstration at every
audio exhibition seemed to feature
the Dark Side track, 'Money'. It's
even now included in the Quadrafile comparison album, where four
programme sides are recorded in
four competing quadraphonic systems, QS, SQ, CD -4 and U D-4.
Perhaps some people now buy the
original album to show off their
systems.
Whatever the reason for Dark
Side's success, it has enabled Pink
Floyd to do something quite
unusual equip a studio for their
own use and run it on a completely
E
Thames Valley Broadcasting
With all this in mind, it seems
astonishing that the station has so
far been so successful. ffrench Blake puts it down to programming policy that avoids blather and
drivel and concentrates on music
and useful local information put
out by what he regards as a top
quality broadcasting team. Certainly the standard of broadcasting
is high. Ex -BBC Paul Hollingdale
does the morning show, and one
morning when I listened ex -BBC
Bruce Wyndham was doing a
guest broadcast. Out of the total
33 station staff, 12 are broadcasters. Mike Matthews, Tony Fox
(ex -LBC) and David Addis are,
along with Paul Hollingdale, the
'old hands', with the other eight
all new to the field when recruited
for the station's opening last
March. Notable for absence was
Simon Dee, whose recruitment to
TVB for a regular show made
headlines last autumn as did his
almost immediate walkout. No
one seems too anxious to talk
about this episode, but it seems to
have involved a dispute over
whether or not Mr Dee should be
expected to interview as well as
play music. Understandably there
isn't too much talk either about
the celebrated occasion last year
when another member of the staff
decided to quit the service in
spectacular fashion, for instance
by breaking the taboo of not commenting on the news, and bringing
up all the wrong faders. A tape of
the occasions is reputed to exist,
and is doubtless by now a sound
collector's item, along with Harold
Wilson's brief encounter with the
young Dimbleby and the Trogs'
unsuccessful attempts to get it
together again in a studio and stop
swearing for a few minutes.
Listening to TVB in my hotel
room the day after visiting the
studios, I recalled one of ffrench Blake's comments. 'People have
got sick of the BBC padded cell
STUDIO SOUND, MARCH 1977
approach', he had told me, 'with
nothing but drivel to fill in the gaps
between music left by their needle
time restrictions. We don't drivel,
we involve the audience. As a
result, 53 per cent of the local listening population tune in to us
once a week, and 25 per cent listen
five days or more.' At the time I
found the figures somewhat hard
to believe, but less so after hearing
one particular broadcast item. A
TVB broadcaster had brought a
local conjurer into the studio to
perform tricks over the air. 'Oh
god !' I thought, but listened out
of fatal fascination. Three listeners
were invited to phone in and
offered a couple of albums for
their trouble. The first was asked
date of birth, the second told to
to 1000, and
pick any number,
the third to name a card in the
pack. In between each call an easy
listening album track was played.
Although the final outcome was
hardly unpredictable (the conjurer
with magical precision had written
down in advance the correct
answer to each question), it's fascination had kept nie listening to
TVB for at least a quarter of an
hour. And of course I'd heard their
commercials as well (including,
incidentally, one made by William
Rushton at Sun). After the conjurer had succeeded with his trick,
to the fall -about astonishment of
the station broadcaster, the local
charity concert at which he was
appearing that night got a mention.
So that made a total broadcasting
score of one free plug for the local
conjurer, one free plug for the local
charity concert, two free albums
for three listeners who got to speak
briefly on the air without boring
the socks off everyone else, and 15
minutes' compulsive listening to
TVB and its commercials for
everyone else. I am not saying it's
perfect; but it sure as hell beats
the sound of Tony Blackburn
Adrian Hope
drivelling.
1
non -commercial basis.
The 'own studio' syndrome and
scenario is now pretty well predictable. A group becomes successful,
makes money and grows tired of
working in other people's studios;
so group builds own studio and
happily records in it for a while;
goes now off on tour leaving
studio empty, but still costing
money to maintain and thus comparable to a boat, otherwise
known as a hole in the water into
which you pour money. Next a
magic solution is found. This
involves going commercial, and
leasing out the studio to earn
money. Finally either of two
things happens. If the studio is
tailor -made to the group, no one
else wants to lease it, so the venture
is a failure; if commercial leasing
is a success, the group can't get in
to its own studio and ends up back
where it started, paying out cash
to tape on someone else's machine.
66
Studio 8 recorders in use at the British Forces
Broadcasting Service studios, London
The tape handling
characteristics of Studio 8
b- oadcast recorders leave
nothing to chance. Designed for
constant 24 -hour daily use, they
safeguard programme material
during recording, mixing, editing
and broadcasting.
Features include tape motion
sensing, servo- controlled
capstan and constant tape
tension -all with full logic control,
for the protection of machine
and tapes. For example,
switching from fast rewind to play
results in a fast but smooth
4
changeover without a hint of
snatch.
There are five basic models,
providing a choice of mechanical
configurations and electronic
facilities. Specifications for a'l
models are conservatively raied,
and minimum maintenance is
required to keep the machines in
peak condition.
The October 1976 edition of
"Studio Sound" has a 5 -page
evaluation of a Studio 8 recorder.
Hugh Ford, summarizing his
comprehensive report,
commented,
The Ferrograph Studio 8 is by
many standards a very cheap
studio machine, but its
performance and general
facilities are by no means in the
`cheap' bracket. Performance
figures quoted by Ferrograph do
not do justice to this recorder,
which is capable of making full
use of the latest low noise and
high output tapes."
Find out why more and more
professional broadcasting
authorities are using Studio 8
recorders. Send for full details
today.
Wilmot Breeden Electronics
Ferrograph
Rendar
Wayne Kerr
Wilmot Breeden Electronics Limited, 442 Bath Road,
Slough, SL1 6BB, England. Telephone: Burnham (06286) 62511 Telex: 647297
Ferrograph Studio 8
the broadcast tape recorder with proven reliability.
65
WORK
But, so far, Floyd have bucked the
system and the syndrome.
Although Floyd percussionist,
Nick Mason, is at pains to explain
that when he says 'I' he usually
means 'We, that is Floyd as a
group', it is clear that it is he who
is mainly responsible for putting
the Floyd studio together. It was
around three -and -a -half years ago
that the group started looking for
a London base in which to rehearse
and store its masses of stage, sound
and lighting equipment. As most
of the musicians lived in North
London, they looked in North
London, but largely without success. Eventually they employed a
friend from Regent Poly College
days to look for them, and in the
fullness of time the three storeys
of a Church Hall, once a part of
the church of St. Stephen, were
revealed unto them in Britannia
Row, Islington. The building was
bought, and plans laid for a
studio. Because this was at a time
before Dark Side of the Moon had
revealed itself as a jackpot and
royalties were not yet in full flood,
the original plans were to build a
cheap studio at a total cost of
around a hundred grand. Gradually, as the group's bank balance
grew, so did the plans for the
studio. But although the final
result is lacking for nothing, it is
very much tailor -made to the
group's requirements. It can for
instance be run with a minimum of
engineering and maintenance staff.
As such it stands a good chance of
remaining, as it currently stands,
available for the sole use of Floyd
whenever they want and need it.
Last year, for instance, between
February and September, the group
was using it three or four days a
week between 11.00 a.m. and
7.00 p.m. to record and mix their
new album, Animals. So apart
from a six-week break in the sum-
66
mer it was in fairly constant use.
Mason admits that the group
tends to work slowly, not by design
or affectation, but by relaxed
nature. `Being prodigal with time,'
is his way of putting it.
He does also envisage the possibility of letting other groups use
it on free days, but more on a personal introduction than on an
`available for hire' basis.
Already there have been a few
visitors, like Arthur Brown (another
name from the UFO era) working
in the gaps left by Floyd.
With the group members having
a predominantly architectural background, dating back to the Poly
days, it is no surprise to see the
Britannia Row studio austere,
rather than plush, and brightly lit,
without dimmers or coloured lights.
`Apart from not liking colours and
dimmers, I think on the whole they
don't get used,' says Mason. 'It's
like the craze of domestic dimmers, people install them and
then switch all their lights on full
anyway.' The walls are bare brick,
or more accurately block lignicite,
which is a mixture of sawdust and
cement. The bare wall look appealed to the architectural eyes of the
group, and they had heard that
lignicite reflects sound far less
than conventional brick. In the
event, they found it reflected rather
more than claimed or anticipated.
But with the help of architect John
Corpe and acoustic consultant Ken
Shearer they were still able to produce a studio and control room
free of unwanted bounce. But the
general feel is one of very live
acoustic, and there are plans to
bring in curtain drapes for the
studio walls when the necessity
arises. By their own admission,
Mason and the rest of the group
tended to work on a fairly intuitive
basis. They had noticed that some
studios sounded good for no particular reason, and were interested
in the idea of building a space
and seeing how it sounded. But
this shouldn't be taken as suggesting that the design was haphazard
-the floor is, for instance, a
concrete raft floated on rubber for
isolation. Even so, Mason acknowledges, with the benefit of
hindsight, that if he had known of
the existence of Tom Hidley three
or four years ago he would have
probably sought his advice before
work started.
Because of the original low
budget, the idea of a Neve desk
was abandoned early on. It was
also intended to make the studio
operable by one engineer with a
minimum of fuss and a maximum
of convenience. Remember, for
instance, that Mason is a performing member of the group for which
the studio was designed. It was a
STUDIO SOUND, MARCH 1977
chance discussion with Steven
Court over monitoring systems
that turned Mason and the group
onto the idea of an MCI package.
At around a third the cost of
custom -made gear, the final package bought was a 24 -track machine
and desk with autolocate plus a
4- track, plus a 2 -track with remote
and reset. The MCI desk is ideal
for single man operation with its
fairly simple equalisation facility;
parametrics are used to provide
whatever extra is needed for individual channels.
The studio is quad capable, with
JBL's at front and rear, but somewhat surprisingly neither the studio
nor the group seems particularly
quad orientated. The new album
is so far scheduled for stereo -only
release and will thus be mixed only
into stereo. Time will be spent on
a quad mix only when the record
company asks for it. And the
thorny question of which quad
system the group would back if
given a hand free of record company
allegiance? Quite simple. Four
track discrete tape was the format
envisaged for Dark Side and everything else is just compromise of
one form or another.
Although a few units of Dolby A
were bought for master mixdowns,
the main emphasis is on dbx, for
which there is full 24 -track facility.
As Mason points out, this is
another advantage of being noncommercial -you can have dbx if
you want it. And he wanted it to
cut down setting up time. Although
ironically the first outside tape to
come in was Dolbied, he adds.
And any regrets on choosing
dbx rather than Dolby? `Everyone
threatened me with pumping
noises,' Mason admits, turning to
maintenance and audio engineers
Nigel Taylor and Brian Humphries
-the only regular studio staff.
'Was it you who threatened me
with pumping noises ?' In the event
no one could remember who had
done the threatening, but all
agreed that so far there hadn't
been any problems. `And if and
when we do find the one odd
signal that upsets the system, we
can always turn it off for that track.'
Upstairs in the ex- church hall,
there's a games room with billiard
tables, a store for lighting equipment and another for sound equipment. All the sound and lighting
gear is available on hire through
the group's Britannia Row Leasing Company. In the basement
there is a vast service station for
keeping studio and lease equipment up to scratch.
The studio floor is equipped
with virtually every keyboard
equipment and amplifier type you
could wish to find or even dream
of, most being duplicated upstairs
so that the studio gear can stay in
the studio while the stage gear gets
knocked about on the road. It's
all part of the master plan to make
recording a relaxed and trouble free business. Likewise, the fold back and microphone lines through
from the control room to the
studio are identified with letters
and numbers in the simplest possible manner. This way, one man
in the control room can stay put
and call unambiguous instructions
through to his colleagues in the
studio.
`It's been designed with drugcrazed idiots in mind,' says Mason
with a grin. But if only to save the
popular press a wasted journey
out to Islington, I have to report
that there isn't a drug-crazed idiot
in sight. Just a somewhat austere,
beautifully equipped and meticulously maintained working environment, lovingly put together by a
member of one of the world's most
successful and musically adventurous groups, far more anxious to
talk about the exciting adventure
of sound techniques and recording
than the mundane business of
Adrian Hope
being a pop star.
AMEK 24/16 M Series console at CASTLE SOUND STUDIOS,EDINBURGH
AMEK
SYSTEMS &
CONTRO.. S
LTD
2nd Floor, Islington Mill,James St.
Salford M3 5HW,Lancs,England
CASTLE
SOUND STUDIOS,11 Dublin St.,
Edinburgh EH1 3PG,Scotland
For professional sound consoles /
For comprehensive multitrack facilities
contact Nick Franks at
contact Calum Malcolm at
061 -834 6747
031 -556 8162
London(PAdivision) Ian Jones,
HHB PA Hire, tel Ruislip (71)73271: FRANCE: Francis Linon, tel (16/) 657 08/2
AUSTRALIA: Con Psarakis, Audio Controls, PO Box /52 ,Norwood SA 5067
tel(08)2672049
67
eview,
MEASUREMENT OF AMPLIFIER
PERFORMANCE
in this edition of
employed in the main,
traditional measurement methods. That is, the
amplifiers have been used to drive passive
loads as opposed to loudspeakers which exhibit,
to say the least, interesting impedance curves
and also have a habit of feeding quite large
amounts of energy back into the amplifiers.
The reviews
of amplifiers
STUDIO SOUND have
These factors, in addition to the habit of
making steady state measurements as opposed
to dynamic measurements, account in part for the
lack of correlation between measured
performance and objective performance.
Unfortunately there are large differences
between the effective modes presented by
loudspeakers so there would not appear to be
any `standard' load which can be used for
testing amplifiers. In fact there is much to
recommend the little found practice of making
the power amplifier part of the loudspeaker.
Another pitfall in amplifier measurement
is the measurement of total harmonic
distortion. Unfortunately, the human ear finds
the higher harmonics for more objectionable
than the lower order harmonics and odd
harmonics more objectionable than even
harmonics. Not only does total harmonic
distortion measurement fail to give any
weighting to conlpensnte for these facts but
also the meter characteristics will virtually
ignore the pulse type distortion products which
are associated with crossover distortion and
which are effectively most objectionable.
There is evidence that swept twin tone
intermodulation measurements show a total
correlation with subjective performance but
here again one is unable to simulate the load
presented by a real loudspeaker and it is known
that some amplifiers take exception to rapid
changes of load impedance and phase angle
with varying. frequency.
Studer A68 stereo power amplifier
MANUFACTURER'S SPECIFICATION
Crosstalk:
80 dB at
Nominal power output: (30 Hz to 15 kHz, both
channels driven) 100W per channel into 8 ohms;
175W per channel into 4 ohms.
Nominal power output: mono operation 350W into
8 ohms.
Power output: at threshold of limiting: typ 150W
Into8ohms (1 % the one channel only); typ250W into
4 ohms; typ 400W into 8 ohms mono operation.
Frequency response: 30 Hz to 15 kHz +0, -0.5 dB;
20 Hz to 20 kHz -i0,- 1.0dB.
Inputs: balanced, floating.
Input impedance: ?5 kohms (stereo).
Input sensitivity :0 deu ... -17 dBu (0 d Bu = 0.775V).
Harmonic distortion: less than 0.1 at any output
level up to nominal power output (typ 0.05" at
1
kHz).
Signal -to -noise ratio: (unweighted rms reading)
better than 100 dB with reference to nominal power
output.
1
(30
Hz...15 kHz) better than
60 dB
(typ
kHz).
Damping factor:
(typ 250 at
Hugh Ford
1
(30 Hz ...15 kHz)
better than
75
kHz).
Level controls: accessible on front panel.
Power requirements: 100, 120, 140, 200, 220,
240V
fuse rating 100... 140V: 8A; fuse rating 200... 240V:
4A.
Power requirements: 100W ...800W.
Dimensions: 483 x 335 x 133 mm.
Weight: 20kg.
Test conditions: Line voltage 220V. Input voltage
+6 dBu
50
(0 dBu
= 0.775V). Impedance of signal source
ohms.
Price:
£528 approx.
Manufacturer: Willi Studer, CH -3105 Regensdorf- Zurich, Switzerland.
UK : FWO Bauch Ltd, 49 Theobald Street, Boreham
Wood, Hertfordshire.
US: Gotham Inc 741 Washington Street, New York
NY 10014
r S HE
A6t' power amplifier is a new product
from the stable of Willi Studer, and like
all his products the standard of engineering has
the feel of Swiss precision and considerable
forethought which adds so much to the 'quality'
of production engineering.
This new power amplifier is clearly aimed at
the studio monitor amplifier market, as
opposed to the brute force sound re- enforcement market, and the overall specification is
sensibly limited to audio frequencies as opposed
to the popular range of amplifiers which are
designed to deafen bats at 100 kHz!
Having regard for the studio monitor amplifier market, the controls on the amplifier are
limited to a screwdriver operated gain control
for each channel and the power on /off switch;
the remaining front panel facilities including a
power on indicator, an overload indicator and
two stereophonic headphone jacks.
To the rear, there is an IEC standard power
input connector with its associated metric fuse
and input voltage selector, all of which are
clearly identified. The audio input comprises
an XLR socket for each of the two channels
which have floating inputs, while the audio
power outputs are available at large size
terminals /banana sockets. While these are
not on standard spacing because of their large
size, there is a considerable advantage in having
good sized connectors.
The remaining facility is a recessed rear panel
switch selecting the normal two channel mode,
or a bridge connected mode. In the latter, the
audio input is from one of the input connectors
and the input impedance becomes halved as a
result of paralleling the two amplifiers before
the input transformer. The audio output is of
course from the two `hot' output terminals and
the rated amplifier load becomes 8 ohms.
70
68
STUDIO SOUND, MARCH 1977
TELEX
tape duplicators
for system flexibility,
reliability and economy.
300 SERIES
cassette
duplicator
available in 2
channel mono or 4 channel stereo formats. Reel
to reel, reel to cassette or
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cassettes, duplicated at 8 times normal
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Frequency response 40- 10,000 Hz. Mono 2 channel (30 ips
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operation) from £920 + VAT.
U.K. Distributors: --
AVCOM SYSTEMS LTD.
PO Box 755 London W
01
-749 2201
12
Telex 897749
69
(
STUDER A68
FREQUENCY
100
50
FIG. 2
Mechanically the amplifier is designed for
rack mounting into t standard 483 mm rack
and is equipped with removable rack mounting
'ears' in addition to two substantial carrying
handles. These are fixed to the sides of the
amplifier which form a large finned heatsink
which extends round the corner to the rear of
the amplifier which itself is in the form of a
sheet metal panel which houses the rear panel
facilities. Similarly the front panel which is in
the form of a thick plate is bolted to the heatsinks and forms a substantial box for the
electronics.
The electronic components are mounted on
six main printed boards, all of which are of
good quality and generally uncrowded; however they do not have component identifications, which in spite of clear layout diagrams
in the excellent service manual, is a hindrance
to servicing. In other respects it is clear that
thought has been given to the servicing problem, as not only is access to the boards good,
but all connections are by means of AMP type
slide-on connectors.
The six boards comprise an rf filter board at
the audio input (an uncommon feature), a
power supply and control board for both
channels, and then audio input boards and
power output boards for each channel. The
latter are mounted adjacent to the power output transistors at the sides of the amplifier, and
I was delighted to note that even the leads to
the power output transistors were connected by
slide-on connectors-this makes it very easy to
locate a blown output transistor.
As is to be expected of Studer, the standard
of wiring and general tidiness of the layout is
beyond reproach with leads and connectors
clearly identified-a truly professional unit.
DISTORTION
500
200
2K
1K
as
5K
7
7
7
7
7
20K
...
in
100W/8f1
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FIG. 3
SMPTE 1M 100W
PEAK EQUIVALENT
INTO 80. DF3
V
m
a
i
117
7111
0
1'1
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INTERMODULATION
DISTORTION ai' CCIF
FIG.7
----
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711111111111711
171M1=171.11
77171EM
FIG. 4
Power output and distortion
As with most power amplifiers the dc supplies
to the output stages are not stabilised, so great
care was taken to make certain that the incoming mains supply was on the nominal 240V.
Likewise the accuracy of loads and the measurement of the output voltage were held to close
tolerances.
Total harmonic distortion was measured
with the Sound Technology 1700A meter, but
because it is my belief that total harmonic
measurement does not tell the whole story so
N
7777:::
77 777
77.
77=
717 ...7177 7 77
771177
77=77
7
77777
7777
7777
777 7117 ==== 7771 7777
1771111
7777
7777
71
171171=177
FIG.9
OUTPUT IMPEDANCE
=1=
Fig.
10
1
08
kHz, 100W, both
0.5
7:o
IMMIMP
7M111.11711E
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20
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200
500
FREDDENCY III Hz
70
STUDIO SOUND, MARCH
1977
1K
2K
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10K
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20K
10K
50K
1J0K
IN Hz
kHz, 801120"
junction with the B & K 2010 hetrodyne
analyser.
Before proceeding with the measurement
results, it should be emphasised that this
amplifier ran quite remarkably cool under any
continuously held sinewave power output, and
at any power output level up to waveform
clipping. At no time did either of the overload
mechanisms come into action, and short of
applying a blow lamp I fail to see how the
amplifier can over heat Two protective stages
are built in; firstly, when the heatsink temperature reaches 90°C, the power to the drive
circuits is removed and the overload lamp
illuminated (so we are told). If heating continues to 120 °C the amplifier takes emergency
action and fires a `crowbar' thyristor across
the main dc supplies, thus blowing the mains
!
far as the sound of an amplifier is concerned,
individual harmonic products were also
measured.
These and the intermodulation distortion in
both the twin tone (difference) method and the
SMPTE method were plotted with the B & K
1902 distortion measurement control unit
allowing swept frequency measurement in con-
fuse.
All that can be done is to take this for
granted, as under any practical conditions up
to the following power output levels for clipping, there was not a hope of reaching a
heatsink temperature of 90 °C.
Total harmonic distortion
20 Hz
one channel 4 ohms 250W
one channel 4 ohms 175W
both channels 4 ohms 175W
one channel 8 ohms 150W
one channel 8 ohms 100W
both channels 8 ohms 100W
bridge connected 8 ohms 350W
0.34%
0.28%
0.35%
0.34%
0.28;ó
0.38%
0.33%
125 Hz
0.05
0.06
0.08
0.07
0.05
0.07
0.07
1
kHz
0.06%
0.04';,,
0.04
0.05
0.03
0.03%
0.03%
10 kHz
0.06
0.03
0.03
0.05"1,
"
0.03%
0.03%
0.03%
kHz
0.07%
0.03%
0.03%
0.05%
0.03%
0.03%
0.04%
15
20 kHz
0.07%
0.04%
0.04%
0.07%
0.04%
0.04%
0.05%
Both channels driven
into
8
ohms
140W
140W
156W
155W
225W
227W
264W
271W
Single channel driven
into
8
ohms
Both channels driven
into
4
ohms
Single channel driven
into
4
ohms
The measurement of total harmonic distortion at the rated output gave the following
results with, in all cases, a very noticeable lack
of crossover distortion as shown in fig. 1 for
100W into 8 ohms at 10 kHz. (See below)
Fig. 2 shows the second and third harmonic
contents at 100W into 8 ohms, it being seen
that for some reason the third harmonic distortion rises at low frequencies; however, as is
seen in fig. 1 the more annoying crossover
products are at a very low level.
The increase in distortion at low frequencies
is confirmed by the intermodulation distortion
as measured by the SMPTE method, the results
being shown in fig. 3 for 100W peak equivalent
sinewave at 100W into 8 ohms with the low
frequency signal set to 60 Hz and an amplitude
ratio of 4:1 between the low and high frequency tones.
Intermodulation distortion as measured by
the CCIF twin tone method gave more pleasing
results as shown in fig. 4 which represents the
swept distortion with a constant difference
frequency of 170 Hz, the distortion being
generally below 0.03 % for any intermodulation
product.
Capacitive loading did not at any time show
any tendency to instability, but the edges of a
fast squarewave overshot as shown in fig. 5 for
a kHz squarewave fed into 8 ohms in parallel
with 2µF.
1
Frequency response and noise
As is to be seen from fig. 6 the frequency
response of the two channels is virtually
identical with -3 dB points at around 6 Hz
and 45 kHz, thus limiting the passband of the
amplifier to audio signals. At rated output
power a similar response was obtained without
any difficulties with overheating or excessive
input power consumption.
Crosstalk related to 100W into 8 ohms was
to a very high standard as is shown in fig. 7
which is a lot better than the manufacturers'
specification and notable for the excellent low
frequency performance.
Likewise the noise performance was excellent, no doubt partly due to the manufacturers'
sense in limiting the passband to the audio
spectrum. Unweighted noise over the band 20
Hz to 20 kHz was found to be 105.2 dB below
100W into 8 ohms, with the `A' weighted rms
noise 108.2 dB below this output level.
Mains hum components were insignificant
and no other undesirable noise effects were
observed.
Inputs and outputs
The maximum input sensitivity for 100W
output into 8 ohms was found to be at 1 kHz
565 mV for one channel and 560 mV for the
72
71
STUDER A68
Stravinsky
made us
do it.
\cry close matching. Operation of the
front panel gain controls provided a reduction
of sensitivity down to 7V nns and it is felt that
other
some applications might warrant a larger range
for the variable controls.
While the input impedance was generally
above the rather peculiar rating of 5000 ohms
minimum, the variation of input impedance
with frequency was excessive as is shown in
fig. 8 and requires care in the selection of the
input line impedance. However, operation of
the front panel gain controls had little effect
upon the input impedance.
On the output end, the output impedance is
shown in fig. 9 which does not give an) cause
for complaint, and neither did the dc offset at
the output which reached a maximum of 45 mV
on the worst channel.
The application of a 100 ms asymmetrical
tone burst running the amplifier 10 dB into
clipping at kHz did not cause any undesirable
dc offset or other nasty effects, as is shown by
the output waveform shown in fig. 10.
Finally the phase shift characteristic as shown
in fig. 11 was excellent within the audio band,
with the anticipated phase shift at high frequencies associated with the high frequency
roll off in the amplifier. As expected the amplifiers rise time was relatively slow at 7.8 zs with
a maximum slew rate of 5.6 \l/µs.
1
and every
Stravinsky
composer who has ever written
music with the range, power and
majesty of "Rites of Spring" ...
music that demands far more
than any stereo can deliver
without adequate amplifier power.
The Phase Linear 700B Power
Amplifier faithfully reproduces the
most difficult passages of the
most demanding recorded music.
It lets all of the music through at
realistic volume levels. You never
have to reach for your volume or
tone controls to prevent clipping.
The 700B has the highest
power, widest frequency
response and lowest distortion of
any stereo amplifier in the world.
Take Stravinsky to your dealer
and listen to what we mean.
.
.
Summary
The Studer
crebtetrn
7(2-1J
THE POWERFUL DIFFERENCE
Please send me
literature on Phase Linear products
SS
Name
-
-
Address
D istnbuted by. C.E.
Hammond & Co. Ltd,
111 Chertsey Road, Byfleet, Surrey KT14
7LA
Telephone. Byfleet 41131 Telex 262525
72
STUDIO SOUND, MARCH
1977
I
,4;'
appears to be a well built
f
FIG. 10
1
kHz,
10
dB into
;
100W, 50 ms!Div
amplifier which runs very cool under any drive
conditions; it should therefore be a good
amplifier for rack mounting applications where
it is required to stack amplifiers for high power
systems.
Frequency response and noise did not give
any cause for complaint and were excellent,
but the third harmonic distortion at low
frequencies tended to be on the high side and
there are amplifiers which are far better performers for overall distortion.
The only other criticism is the rather low and
variable input impedance which could be
annoying, particularly when several amplifiers
are driven in parallel.
Dolby Laboratories a conçu une unité
de réduction du bruit de fond pour chaque
type d'utilisation professionnelle
Applications à l'Enregistrement
et à la Transmission Professionnels
rLoerww
r
Industrie Cinématographique
..
tlI
Codeurs Professionnels pour
Production de Grande Série
a
_1
360
364
Le Dolby 360 est une unite de base du type A pour
la réduction du bruit de tond sur un canal- pour
codage ou décodage. Cet appareil est utilisé
en general comme installation fixe dans le
transfert sur disques et aux entrees ou sorties de
lignes de transmission, la selection des fonctions
se fait manuellement.
Le Dolby 364. réducteur j1e bruit de fond pour le
cinéma. est conçu au depart pourÈtre utilise avec
des pellicules en son optique ou magnétique
codes selon le caractéristique Dolby A. Le 364
comprend aussi un filtre standard classique pour
les bandes conventionnelles. un circuit de
nettoyage pour les pellicules usées ou abîmées,
et la possibilité de lire des pistes magnétiques
avec ou sans système de codage Dolby,
330
copie de bandes est une unité
(ualite professionnelle possédant les
caractéristiques Dolby B Faraud public).
L'appareil sert a coder les bandes matrices pour
la copie á grande vitesse des cassettes.
cartouches et bandes "Dolby'. Le 330 est un
appareil à deux canaux.
Le Dolby 330 pour
do
t_........-_cusz
361
Le Dolby 361 est identioue au 360. c'est aussi un
réducteur du bruit de fond sur un canal. mais une
commutation par relais permet de télécommander
ses fonctions a partir d'un magnetophone de
studio.
F
E2
L équalizer
cinéma type E 2 est destiné à être
accouplé au 364. Il a éte étudié spécialement pour
résoudre les problèmes de répartitions des
fréquences sonores dans les salles de cinéma.
Utilisé confointement au 364 et à une pellicule a
son optique codé en Dolby, le E 2 permet de
parfaire l'acoustique de la salle de spectacle
sans transformer le matériel déjà existant.
'-
;'
334
Le Dolby 334 permet aux stations de radio
démettre un message codé Dolby en modulation
de fréquence. selon le procédé du Dolby B.
L'appareil réduit également la préaccentuation
des hautes fréquences á 25 microsecondes. ce
qui rend moins nécessaire la limitation des hautes
fréquences et améliore nettement la qualité de
la réception.
Séries M
Le Dolby M16H Type A est spécialement destiné
l'enregistrement professionnel multipiste. Il
comprend 16 unités de reduction du bruit de fond,
le tout groupe dans un coffret compact. haut de
10.5 pouces seulement 1267 mm). La modele
M8H est une version 8 pistes_ Le M8XH peut
s'adjoindre rr un lntl6H pour travailler sur 24 pistes.
à
Modules de Réduction du Bruit
de Fond
CP100
Le Dolby CP100 Cinema Processor est connu pour
la reproduction des pellicules en tous les formats
de sen coursants et a present prevoyables, y
compris le son optique ou magnétique
conventionnel, le son monophonique sur piste
optique codee en Dolby. et les nouvelles
productions en son stéréo sur piste optique.
Jusqu'a trois modules pour la réduction du bruit Mn
fond peuvent être incorpores. Normalement, trois
nodules pour l'égalisation du theàue comme
utilisé dans le E2. seront inclus. Au total il y a des
facilites pour cinque modules [rouit -égalisation.
plus. un décodeur tetraphonique externe peut
être attaché.
En
Controleur (Type A)
Cat 22
Le module Cat 22 pour la réduction du bruit de
fond est la plaquette de base, utilisée darns tous
les appareils de type A. Le Cat 22 est disponible
comme pièce détachée ou en grande quantité
pour des installations à grande échelle. Une
version demi vitesse de ce module, le Cat 40 est
DO
Dolby
Dolby
Du IOylise et le symbole double -D
sont des marques éunesces
.
également di sponi blé.
Dolby Laboratories
Cat 35
731
Le Cat 35 permet la vérification rapide des
performances d'un Cat 22. sans démontage de
l'unité et sans Intervention d'autre matériel
de contr,.le
346 Clapham Road London SW9 9AP
01 -720 1111 Telex 919109
Sansome Street San Francisco CA 94111
(415) 392-0300 Telex 34409
y
73
Altec power amplifier 9440A
/ILII
I
Hugh Ford
11111111111111
t
l i t
t
a basic power amplifier the Altec 9440A
has some unusual features, in that it can
be switched to operate in either a twin channel
or bridge mode whereby it can drive in excess
of 800W into 8 ohms compared with 200W
into 8 ohms (or over 400W into 4 ohms) in the
dual channel mode.
Furthermore, the front panel switch which
provides this facility has two further positions,
such that the potential power output can be
reduced to 40% of the rated power output in
either mode. Additional front panel features
include twin illuminated vu meters which are
associated with individual meter range switches
which permit the meter gain to be increased
by 10 dB or 20 dB for monitoring lower power
outputs. The final front panel facilities are
individual volume controls for each channel
and the power on /off switch.
To the rear of the unit the incoming power
is via a fixed lead, which like all fixed leads is
A single
bound to be the wrong length
identified fuse provides protection for the
amplifier and the two rear panel switched power
outlets which are of the American three -pin
variety. An optionally transformer coupled
audio input is provided via three -pin XLR -type
sockets which are unused except when the
optional transformers are fitted to octal sockets
within the amplifier. In the review sample
these were not fitted, in which case the audio
input is via two unbalanced 6.35 mm two -pole
jack sockets. An uncommon feature is that
these sockets are duplicated to provide feeds of
audio to additional amplifiers which may be
required to work in parallel. However, there
is no buffering such that the load on the
incoming audio feed is the full amplifier load
in parallel.
Finally the power output to the loudspeakers
is by four banana socket /terminals which are
on the standard 19.05 mm spacing. In the
twin channel mode two pairs of these connectors are used, and in the bridge connected
mode the two inner connectors provide a
balanced mono speaker output.
Mechanically the amplifier is of relatively
sturdy construction with a cast (but not
particularly thick) front panel joined to a
massive, specially cast, heatsink forming the
rear panel with sheet steel sides. The front
panel is designed for mounting in a standard
483 mm rack and is equipped with two heavyduty handles for portable use, in which
circumstances give good protection to the front
panel controls and meters. Similarly the rear
panel facilities are well protected, and a cover
which can accommodate two cooling fans
(optional) protects the heatsink flanges.
Internally the electronics are accommodated
AS
!
MANUFACTURER'S SPECIFICATION:
Type: two- channel basic power amplifier with provision for two optional 15335A plug -in line transformers for balanced input.
Gain : 55.7 dB with 15335A bridging 600 ohm line with
8 ohm load. 58.7 dB with 15335A bridging 600 ohm line
with 4 ohm load. 61.7 dB with 15335A bridging 600
ohm line in bridge (mono) mode with 8 ohm load.
Input sensitivity : 0.6V rms for rated output.
Power output with single channel driven: 200W
per channel into 8 ohms from 20 Hz to 20 kHz at less
than 0.1
thd. Typically greater than 250W per
channel into 8 ohms at 1 kHz at less than 0.01 % thd.
400W per channel into 4 ohms from 20 Hz to 20 kHz
at less than 0.25% thd. Typically greater than 450W
per channel into 4 ohms at 1 kHz at less than 0.05°
thd.
Power output with both channels driven: 200W per
channel into 8 ohms from 20 Hz to 20 kHz at less than
0.25";, thd. 400W per channel into 4 ohms at 1 kHz
at less than 0.25% thd.
Power output bridge (mono) operation: greater
than 800W into 8 ohms at 1 kHz at less than 0.25 °'0
thd.
Im distortion (single channel driven): less than
0.1 % from 0.01W to 250W into 8 ohms (60 Hz, 7 kHz,
4:1). Less than 0.1
from 0.01 W to 450W into 4 ohms
(60 Hz, 7 kHz, 4:1).
Frequency response (direct input):
0.25 dB at
1W (8 ohms) from 20 Hz to 20 kHz. ±3 dB at 1W
from
(8 ohms)
5 Hz to 100 kHz.
Input impedance: 15 000 ohms (nominal for all
inputs).
Load impedance:
1
(primary power).
Indicators: two illuminated meters indicating full
wave average output level with ranges of 0 dB,
-10 dB and -20 dB (ref 40V output).
Connectors: two Cannon XLR3 -31 input receptacles. Two phone jack input receptacles. Four five way binding post input jacks. Two phone jack
multiple receptacles (to connect additional amplifiers). 1.5m, 3 -wire, 16GA power cord with NEMA
5 -15P plug. Two ac power receptacles, switched.
Total maximum power handling capacity 150W.
Power requirements: 120/240V ac, 50/60 Hz. 100W
at zero signal, 850W at 3 rated output (4 ohms) with
both channels driven at 1 kHz. 1500W at rated output
(4 ohms) with both channels driven at 1 kHz.
Amplifier protection : active output stage with
voltage /current limiting and dual voltage -level power
supply to reduce power output to 40% of rated output. Control circuitry monitors excessive heat sink
temperature, mismatch of load impedance and
setting of power output switch.
Load protection : output relay delays turn -on of
output power for 5s; provides instant turn -off of
output power and removal of load in case of presence
of dc voltage in the output.
Operating temperature range: up to +55 °C
ambient.
Dimensions (hwd):
17.8 x 48.3 x 27.9 cm
(without
fans).
ohms or greater per channel.
8 ohms or greater in bridge (mono) mode.
Output impedance: less than 0.1 ohm in dual mode
at 1 kHz. Less than 0.2 ohm in bridge (mono) mode
at kHz.
Signal -to -noise ratio: greater than 100 dB and
20 kHz noise bandwidth; equivalent to 5.5 pV maximum input noise or -103 dBm (600 ohms).
Channel separation: greater than 80 dB at 1k Hz
and 8 ohm loads.
Controls: two volume controls, continuously vari4
1
74
able. Two meter range switches having 0 dB, -10 dB
and -20 dB ranges (ref 0 dB =40V output), one
power output switch, to select mode (mono or dual)
and clipping power percentage (40% or 100 %) in
either mono or dual mode. One power on /off switch
STUDIO SOUND, MARCH 1977
Weight:
25.6 kg.
Enclosure : rack mount chassis with provision for
mounting two accessory fans of heat sink shroud.
Accessories: Altec 15335A line transformer. Axial
fan 11.9 cm, 120V.
Price: £1,000.
Manufacturer: Altec Sound Products Division,
South Manchester Avenue, Anaheim,
California 92803, USA.
UK agent: Altec Sound Products Ltd, 17 Park
1515
Place. Stevenage, Hertordshire.
76
LOW COST, HIGH QUALITY,
r
01
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j+
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CONSOLE
o.
.,,
EM®
16 -TRACK
44 4 4
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11164
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1114***`!
From
RAINDIRK LIMITED,
Downham Market, Norfolk
Telephone: 03663 -2165 & 3617
1
A,Ee611sMAT
APOLLO
FRANCE
ELECTRONICS
POWER AMPLIFICATION
PROFESSIONAL
audio plug -in units
more than 20 models
input channel, amplif
equalisers, compressors,
expanders, generators,
line amplifiers, etc
...
PERFORMANCE AND
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COST...
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24 PINS DIL
33
-HM80:
x 20 x 15mm
general purpose AC
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applications free)
-HM70: low noise 70 dB gain
micro preamplifier
-HM30: Compressor limiter
34 dB comp. 0.3% THD
Application data on request /AES PARIS, std B12
BY MUSTANG
.
o
Our
u
SS.100 and SS.50 are economical amplifiers with outputs
of up to 150 and 80 Watts RMS into 8 -15 ohms, typical THD
figures being 0.17, slewing rate > IOv/f,s, noise > 90dB
down, zero level input, and full electronic protection.
Considering these points with their proven reliability and
robust construction, plug in output transistors and driver
board, optional balanced input and I00V line output, and
virtually ex stock despatches we reckon we take some beating!
Contact us now for the full technical specifications.
Manufacturers of mixers, integrated mixer amplifiers and slave amplifiers,
studio power amplifiers, transformers, lighting control equipment and
cabinets for the home and export markets.
Contact us for full illustrated technical brochures.
MUSTANG
COMMUNICATIONS
Nelson Street, Scarborough,
North Yorkshire Y012 7SZ
England
Telephone
0723 -63298
22 RUE STE AMBROISE -PARIS 7501I-FRANCE
73
ALTEC 9440A POWER
AMPLIFIER
111M
111 il
=1111=111
11111
Or/
FIG.I
HARMONIC DISTORTION
on five good quality printed boards, one of
which is a large 'control' board located behind
the front panel, two 'driver' boards located on
the side panels and two 'power' boards being
soldered to the power transistors on the rear
heatsink.
While most connections are by
connectors as opposed to soldered joints, the
rear 'power' boards must be right pigs to
service, this not being assisted by a complete
lack of component identifications on any of
the boards or layout diagrams in the instruction
book which is, in other respects, a sensible
document.
AT
=..
111=1111
111M11=11MMIMI
1
channel
$ ohm
driven
Il
1
channel
2
load-both channels
266W
254W
275W
296W
420W
435W
501W
490W
ohm load-single channel
driven
4 ohm load-both channels
driven
4 ohm
load-single channel
driven
As is usual with solid state amplifiers the
distortion increases very rapidly with increased
power around to clipping point, but it was
found that distortion remained practically
constant as the output power was lowered
from the rated output down to very low output
powers.
As is shown in fig. 1 the second and third
harmonic products remained well below the
specification at the rated output of 200W into
8 ohms and the following figures for total
harmonic distortion generally confirm the
specification:
In the bridge connected mode at powers
approaching the rated 800W the distortion
pattern varied with the frequency of the mains
supply, such that the distortion content was
cyclic at mains frequency, hence the two figures
quoted for low frequency distortion in this
mode.
Generally the harmonic content as measured
76
STUDIO SOUND, MARCH 1977
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resistors which have a peak power handling
capacity of 6 kW for five seconds!
Total harmonic distortion was measured
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which intermodulation products and individual
harmonics were determined with the B & K
2010 hetrodyne analyser in conjunction with
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the mains voltage and output voltage with
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As with other high power
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from air blast cooled 4-0.5% tolerance
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Our new Bantam range gives a space
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PANELS AND ASSEMBLIES
No supplier offers a wider range of panels,
inserts and accessories for just about any
1IMINIIIMININ
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20X
50K
100K
200K
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by means of a total harmonic is not particularly
meaningful, for as is shown in fig. 2 crossover
distortion can form a large part of the measured
result.
At this juncture it must be mentioned that
overheating automatically reduced the output
power to a nominal 40% (measured as 86W
versus 200W); however, the form of power
output limiting was found to introduce
asymmetrical waveform clipping and furthermore there is no visible warning that the
amplifier has overheated and reduced its power
capability.
Turning to other forms of distortion, the
difference tone intermodulation distortion
between 200 Hz and 200 kHz with two tones
separated by 170 Hz is shown to be satisfactory
FIG. 2
FIG. 5
1 kHz, into 801121.1F,1W
10
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I
IF YOU NEED
....
....
configuration. And you can get them in
any stage of assembly . . . individual
components, sub-assemblies, or complete
pre-wired and connectorised assemblies
ready to install.
78
kHz, 200W, 80 0.034% 1/id
JACKS AND PLUGS
Singles . . twins . . . back-to-back
.
.
.
.
2+1 ... patch and switchboard cords ..
most standard types are available for
immediate off-the-shelf delivery.
For information on these and our range
of B.P.O. type components contact:
COMMUNICATION ACCESSORIES and
EQUIPMENT LIMITED.
20
450W
400W
400W
250W
200W
800W
4
4
4
8
8
8
ohms
ohms
ohms
ohms
ohms
ohms
Hz
Total harmonic distortion
125 Hz
10 kHz
1 kHz
one channel
both channels
one channel
one channel
one channel
bridge connected
**Continuous operation at high frequencies produced
large variation in distortion performance.
0.015"
0.015%
0.01/0.05'
a
0.015%
0.015%
0.3%
0.3%
0.3%
0.014%
0.015%
0.45%
20
kHz
CAE LIMITED
0.15
0.03
4.*
0.07%
very rapid rise in heatsink temperature and a consequent
70/80 AKEMAN STREET,
TRING, HERTS HP23 2PJ
Tel. (044 282) 4011
Telex : 82362 A/B BATELCOM
77
ALTEC 9440A POWER
AMPLIFIER
rr
as in fig. 3 and similarly the intermodulation
distortion by the SMPTE method with a 60 Hz
tone and a variable high frequency is shown
in fig. 4.
The use of capacitive loading did not produce
any signs of instability in the amplifier, but
did produce a certain amount of overshoot on
fast edges as is shown in fig. 5 which shows the
result of feeding a 1 kHz squarewave into a
load of 8 ohms in parallel with 2 v.F.
Frequency response and noise
Fig. 6 shows the frequency response of the
two channels at a power of 1W into 8 ohms, it
being seen that the response is within +0.4 dB
from 20 Hz to 20 kHz for either channel. The
power response was creditably not far short of
this at 200W into 8 ohms. Under this condition
the crosstalk between channels was very good
as is shown in fig. 7 which shows that the
crosstalk is 80 or 90 dB down at frequencies
where it really matters.
On the noise front the `A' weighted noise in
the output was found to be -101.4 dB below
200W output into 8 ohms, but the unweighted
noise over the band 20 Hz to 20 kHz was found
to be -91.2 dB as a result of mains hum and
its harmonics. However, as the review amplifier was a demonstration unit which had been
subjected to considerable use, this figure may
well not be typical of the model.
Inputs and outputs
The input sensitivity for 200W into 8 ohms
was found to be 523 mV on one channel and
522 mV on the other channel at 1 kHz: remarkably close matching. The input impedance
varied from 15 900 ohms at the maximum
gain setting to 26 200 ohms at minimum gain,
a variation which should not cause any
embarrassment when bridging 600 ohm lines.
As is shown in fig. 8 the output impedance
is sensibly constant at 0.05 ohms below kHz,
above which it rises to a maximum of 0.7 ohms
within the audio band at 20 kHz.
Dc offset at the output reached a maximum
of 11 mV which is completely satisfactory, and
various tests failed to show any undesirable
1
- ....
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.......MM.... ...-.-M-.......-....m.s.. ala
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mot
200
100
50
500
1K
2K
5K
10K
C:I::'.:
eliMIMMOSMOM
20K
5"K
10K
FREOOENCY IN Hz
form of dc in the output under overload
conditions, the result of bursting the amplifier
into 10 dB of overload with an asymmetrical
sinewave being shown in fig.
FIG. 9
50 ms /div,
1
kHz
9.
Other matters
Investigations into the qualities of the two
vu meters showed that they were not to the
ASA standard, but that they needed about the
same margin between zero vu and peak signal
as the standard instrument. Thus, in normal
operation the meter switch should be set to
the -10 dB position if the meters are to be used
to indicate amplifier overload -no mention is
made of this in the instruction book
As shown in fig. 10 the overall phase shift in
the audio band is respectably small, and outside
the audio band there is no cause for concern
about stability at high frequencies. A final
note is that the rise time was measured as 3 [is,
with an associated slew rate of 8 V /µs.
!
Cartridge impedance interaction on frequency
response
High inductance cartridge. Less than 0.2dB
30Hz-20KHz -82dB, 0.008%
Low frequency response
18dB /octave
-3dB at 24Hz
Intermodulation distortion 50Hz + 7KHz, 4:1
Output +IOdBV.7 -9dB 0.003 %, limit of measurement. Group delay relative to I KHz -15ms at 30Hz
Noise 20Hz -20KHz mean reading meter
Square wave distortion
Short circuit input
-70dBV.7
Pre-emphasised I KHz square wave input, 600mV pk -pk
Cartridge source, 100mH
-67dBV.7
Even harmonic generation -70dB any harmonic
78
MMMa
MOMO
==O0 C
===MOOO
=_O_O:'.'.:CC=C::====OO :'.====OC::'.000===OO::::
:.::====OC::::=00=0::::
I
Surrey Electronics
-..--
MISMNIMIMIN
:::+....-:::::CCO::::CCCO::::
:::::__
:.:......:
....._-.....
.......i..
-....
10
MOp_PHASE
intermodulation distortion.
T. Holman New Factors in Phonograph Preamplifier Design" JAES Vol. 24 No. 4 May 1976.
kHz at 6 mV set for OdBV.7 output. Loaded 600 ohms.
30Hz -20KHz below noise
30Hz -20KHz below noise
I KHz
-88dB, 0.004%
INOMMEM
__M_-
Magnetic cartridge to balanced lines with the highest quality. Mains powered. Lower distortion and continued
attention to cartridge impedance interaction effects.
FOR BROADCASTING, DISC MONITORING AND
TRANSFER.
The square wave distortion figure is a revealing guide to performance on asymmetrical signals and transient
Output
OdBV.7
Output + 10dBV.7
Output + 20dBV.7
-...
_CO_O_::::OCC_=COOT::::CO:00:00::::CCCCCO;::::
-....
CO:::::CC[LttiifrO-:::=CC_M_--....,-...
-...CCÇ:::' ==O:
STEREO DISC AMPLIFIER 2
Distortion
-
a=B:E:=====_5EE======8E5E===8=5?:é
_____-=::::____:::::
___==
-x:=
------------- EEo===---...-------...
=MOC:
====0 _=_=
--- ::=OC=O::C'.7C.___
=='':
...._::'.::
C:::::=CO:::::=C=COO::::=l=C=:::::__::'.:
The Forge, Lucks Green, Cranleigh, Surrey
G
U6 7BG (STD 04866) 5997
STUDIO SOUND, MARCH 1977
www.americanradiohistory.com
Summary
This amplifier offers a substantial power
output, but does not rank amongst the lowest
distortion amplifiers. It is, however, well built
and should withstand the rigours of mobile
and pa use. Clearly the optional cooling fans
should be fitted if the maximum power capability is likely to be required, and like amplifiers
which use relatively slow output devices, this
amplifier takes exception to very high frequency
inputs. In this circumstance the mains input
requirement goes way up, and leads to very
rapid heating, automatic lowering of the output
capability and consequent lower output
capability without warning.
The input arrangements are unusual with
the facility for looping a series of amplifiers
together by means of jack leads, and this is a
nice feature for pa work, as is the inbuilt
facility for switching to bridge (mono)
operation.
On the metering side the meters provide a
useful facility if they are set to the -10 dB
attenuator setting, but my preference is for a
peak reading indicator which gives an alarm
as overload is approached.
We Capture ANY Sound!
AKG -the right microphoie
for every application
The cheering of the spectators at the Olympic Games.
The roaring of a formula racing car. The singing of the
greatest singers in the world. The capturing of those
precious moments in family life, on tape. Wherever crystal
clear reproducing or recording is required you will find AKG,
Please send me by return, Informations about
I
sound reinforcement
musicians microphones
may be
-
182/4 Campden Hill
Name
4,e
for every applicarion there is a specially designee
AKG microphone. However high your quality requirements
Address
Country
ó
Please recommend the best mic for my particular application
AKG can exceed them.
Road
Kensington
AIKG
studio microphones
E headpnones
Equipment Ltd. London W8 7AS Telephone 01.229.3695
AKG EQUIPMENT LTD 182184 Campden Hill Road Kensington London W 8 7AS Telephone 01.229 3695
AUSTRIA, AKG Akustische und Kino -Gerate Ges m. b. H. Wien. Brunhildengasse 1, A -1150 Wien. TF. (0222) 92 16 47
BE_GIUM, Radelco P V B A., italiele 179. Antwerpen,
TF: 03 -337 880
CANADA, PHILIPS Audio-Video Systems, 200 Consumers Road, Suite 105, Willowdale, Ontario M2J 494. Canada, TF 494 1453
DENMARK, S.C. Sound,
Brondbyostervej 84, Dk -2650 Hvidovre, TF. 01.471222
FINLAND, Nores & Co OY. Fabianinkatu 32, Helsinki 10, TF, 13360
FRANCE. Reditec, 27ter, Rue du Progrés,
F -93107 Montreuil, TE: 3282580
GERMANY, Akustische und Kmogerate Gesellschaft m.b H., Bodenseestraße 226 -230, D -8 München 60. TF 089/873011
ITALY.
M. Casale Bauer, Via IV Novembre N 6 -8, 40057 Cadnano d. Granarolo, P.0 Box CP 753, 40100 Bologna. TF.
0 51/7 6684 8
NETHERLANDS, Rema Ellectrorics, Isarweg 6,.
Amsterdam, P. O. Box 8501, 1015 Sloterdijk, TF, 114959
NORWAY. J M. Felnng A /S, P. 0. Bros 101 - Bryn, Oslo 6, TE. (02)686360
SPAIN. Nea:ecnica SASE_ Marques de
Urqulio, 44. Madrid - B, TF: 248 96 02
SWEDEN, Harry Tnellmoc AB, Hornsgatan 89, 5-11721 Stockholm, TF 08- 680745
SWITZERLAND, Audio Electronic AG,
Lohwisstraße 24. CH -8123 Ebmatingen, TF: 9714 7C
USA, PHILIPS Audio -Video Systems Corp 91 McKee Drive. Mahwah. New Jersey 07430. IF: 2D1-529 -5900
-
,
.
www.americanradiohistory.com
Dunlap Clarke Dreadnaught
power amplifier
MANUFACTURER'S SPECIFICATION
Continuous power output per channel with both
channels driven into 8 ohms across 20 to 20 000 Hz at
less than 0.25% total harmonic distortion: 250W.
Continuous power output per channel with both
channels driven into 4 ohms across 20 to 20 000 Hz
at less than 0.25% total harmonic distortion: 500W.
Total harmonic distortion from 0.1W to 250W per
channel with both channels driven into 8 ohms across
typical.
20 to 20 000 Hz: 0.25'' maximum, 0.025
Intermodulation distortion at60 and 7000 Hz mixed
4:1 at any power from 0.01W to 250W into 8 ohms:
0.1 "1, maximum, 0.025% typical.
Frequency response: 250W per channel, 20 to
"
20 000 Hz,
0.5 dB.
Frequency response: at 1W per channel,
20 to
20 000 Hz, __0.05 dB.
Slew rate: greater than 25 Vfps.
Signal -to -noise ratio: 100 dB minimum.
Load impedance: 2 ohms or greater.
Input impedance: 100 kohms.
Input sensitivity: 1.75V rms for full output.
Power line requirements: 120V ac, 60 Hz
240V
ac 50 Hz.
Power consumption at maximum rated power:
1000W.
Power consumption at idle: 50W maximum.
Temperature rise at full power (fan on low (silent)
speed): less than 40-C.
Dimensions (whd): 483
Net weight: 32 kg.
x 178 x 305
mm.
Manufacturer: Dunlap Clarke Electronics, 230
Calvary Street, Waltham, Massachusetts 02154,
USA.
UK agent: Exposure Electronics, Richardson Road,
Hove, Sussex.
were fortunate enough to receive a
prototype of the Dreadnaught 1000 for
review (see comments at end) which is the big
brother of the Dreadnaught .500; this is identical
except for having less power output; the 1000
offers 500W per channel into 4 ohms as
opposed to the 300W per channel of the .500
model.
The amplifiers are twin channel units without
provision for bridge operation, and employ ten
WE
1000
Hugh Ford
output transistors in each output stage. These
transistors are mounted on large heatsinks at
the sides of the amplifier, there being a cooling
fan associated with each side of the amplifier.
A three position switch at the rear of the
amplifier controls the fan speed between fast,
slow and off. In the fast setting the fans were
incredibly noisy, generating in excess of 50 dBA
spl one metre from the amplifier on the bench,
and the slow operation was little better.
While it is felt that for many applications the
fans are not necessary, their noise would make
the amplifier quite unusable in quiet environments such as a studio control room. Also it
is rather surprising that the fan speed has not
been thermostatically controlled by the heat sink temperature, as opposed to manual
control.
Reverting to the construction of the amplifier, the main body is formed from folded alloy
sheet which forms a substantial box on to which
is mounted a thick alloy front panel provided
with holes for mounting into a standard 483 mm
rack. Because of the thin material used for the
heatsink fins, some form of mechanical protection is essential for non -racking applications.
Within the amplifier, good quality glassfibre
printed boards are used, but no component
identifications are provided. There is one fixed
board and one plug-in board for each channel
in addition to a small board associated with the
power supplies.
The internal appearance of the review sample
was decidedly scruffy with untidy wiring and
liberal use of what appeared to be silicone
rubber compound for securing components and
locking the two pre -set potentiometers in each
channel. Also rather peculiar was the illumination for the two front panel vu meters, this
taking the form of two large 'Christmas Tree'
type lamps within the amplifier. The vu meters
have standard scaling and operate in conjunction with a sensitivity switch for each meter;
this providing five positions.
In the normal position the zero vu indication
corresponded to maximum sinewave output,
with the other positions providing a meter gain
of 3 dB, 10 dB or 20 dB and a meter off position.
Clearly in view of the ballistics of the standard
vu meter the 10 dB gain position should be
used for normal operation, but no mention is
made of this.
The remaining front panel facilities comprise
a level potentiometer for each channel and an
illuminated mains on /off switch. The construction of this switch was such that there was
a very small clearance between metal parts
connected to the chassis and mains wiring;
certainly his arrangement would not pass
British Standard 415 safety requirements, and I
regard this feature as potentially dangerous.
To the rear of the amplifier, there is a fixed
mains lead of the self-coiling type as used on
telephones, and three imperial size fuses which
are properly identified. The audio inputs are
by means of the horrible 'phono' socket, which
strikes me as most odd for a professional
amplifier.
On the other hand the audio outputs are in
the form of duplicated terminals /banana
sockets all on the standard 19 mm spacing;
certainly the duplication of the output terminals
will be appreciated in many pa applications.
1.
Power output and distortion
As with all really high power amplifiers,
there is a problem of finding a suitably stable
load for testing; I use and recommend the
300W metal clad resistors type HSC300 which
are available from the CGS Resistor Co, of
Lymington in Hampshire. A suitable set of
these resistors and an accurate digital voltmeter for measuring the incoming power line
and also the output voltage are ideal for
accurate measurements.
Both individual harmonic distortion and
total harmonic distortion were measured, but
unfortunately the amplifier decided to sacrifice
the output transistors in one channel during
crosstalk measurements at 250W into 8 ohms,
so measurement of distortion with both
channels driven does not appear in the
following table:
Total harmonic distortion
500W into 4 ohms
20 Hz
125 Hz
**
**
1
kHz
0.02
:,,
10 kHz
20 kHz
0.04^,;,
0.07%
250W into 8 ohms
0.55%
0.37%
0.02%
0.37"x,
0.64%
1W into 8 ohms
0.50%
0.45,;,
0.029%
0.37%
0.55%
* *At low frequencies into 4 ohms the apparent distortion was affected by high frequency instability.
Waveform clipping occurred at just over
500W into 4 ohms or 250W into 8 ohms but the
amplifier was capable of delivering full power
over the audio band from 20 Hz to 20 kHz.
The individual second and third harmonic
products with the amplifier driving 250W per
channel with both channels driven in shown in
fig. 1 which for some reason does not give good
correlation with the total harmonic measurements. However, examination of the individual
harmonics at 1W output indicated quite good
performance with the third harmonic at a
constant 0.03 % and the second harmonic
generally at a lower level.
Intermodulation distortion was measured by
both the SMPTE method and by the swept
82
80
STUDIO SOUND, MARCH
1977
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Control over every parameter has
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00
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ON
a
2
fco
+x+
,
00
f
L9
RF DAMPING
>sSO-
2S'
VO,[
,;D
AMP
250
O,+
REVERE TIME
SECONDS
PROGRAM
LF
FILTER
Quad /Eight Electronics
Quad /Eight International
11929 Vose St., North Hollywood, CA 91605
(213) 764 -1516 Telex: 662 -446
DUNLAP CLARKE
1000
difference tone method using tones separated
by 170 Hz. Fig. 2 illustrates the difference tone
distortion in terms of the odd difference frequency which was the largest product, while
fig. 3 shows the SMPTE method distortion
with a 60 Hz tone and a higher frequency tone
in the amplitude ratio 4:1.
The crossover distortion situation is shown
in fig. 4 which shows the distortion of a 10 kHz
sinewave at 1W into 8 ohms, and I regard this
crossover distortion as rather excessive.
While capacitive loading did not generally
upset the amplifier, the effect of a 8 ohm in
load on a 1 kHz squarewave
parallel with 2
is shown in fig. 5. This shows a fairly sub-
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BOTH CHANNELS
DRIVEN
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20
100
200
500
1
FREQUENCY IN
FIG. 2
Frequency response and noise
The overall frequency response into a 8 ohm
load is shown in fig. 6 for both 1W output per
channel and 250W per channel and shows that
the amplifier can `deliver the goods' at high
powers.
At subsonic frequencies, the protection
circuits disenable the amplifier in order to protect loudspeakers, so no useful power output
can exist at frequencies which create loud-
C
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stantial overshoot.
I had hoped to double check the above results
and also to investigate the performance into
other loads, however I have already mentioned
that one channel departed this life -this problem was very quickly rectified by the UK agents
who showed that it was a quick and simple
task to replace output devices, but it is sad to
report that subsequently both channels blew -up
and there just wasn't time to repeat the servicing
exercise. However, it is only fair to report that
whilst the output devices failed, no damage
occurred to the driver stages -many amplifiers
would just go up in smoke with their output
transistors shorted.
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INTERMODULATION
DISTORTION
DIFFERENCE TONE DF3
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0.19.
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DISTORTION BY SMPTE
TONE 60Hz 20W/811
10H
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2K
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1K
2K
5K
10K
20K
50K
í00K
200K
FREOUENCY IN Hz
FIG. 4 10 kHz, 1W,
FIG. 5
1
speaker damage. While this type of protection
circuit is generally a good idea, the reset time
in this amplifier was about two minutes and it
was necessary to remove the mains power to
reset the amplifier. This may be all very well in
domestic use, but such a procedure can hardly
be tolerated in pa and similar work.
Crosstalk between the two channels was very
good as shown in fig. 7 in relation to 250W into
8 ohms and, having regard to this power output, the noise was also good at -98.7 dB over
the band 20 Hz to 20kHz, or -104.6 dB 'A'
weighted.
8SZ
kHz, 8521/2µF
Inputs and outputs
Dc offset at the output was minimal and the
amplifier did not do anything untoward on
asymmetrical overload, the result of driving the
amplifier 10 dB into clipping with an asymmetrical 100 ms burst of 1 kHz being shown in
fig. 8 which illustrates a smooth recovery.
82
STUDIO SOUND, MARCH
1977
The output impedance as shown in fig. 9
remained respectably low at all audio frequencies, being a constant 0.05 ohms in the
lower audio band.
On the input end the sensitivity for 250W
per channel into 8 ohms was found to be
1.703V rms, but unfortunately I did not have
the opportunity to measure the input impedance of the unbalanced inputs; while on this
subject I would rather have seen provision for
a balanced input for professional use.
Other matters
The measurement of the slew rate gave a
figure of 12 V /µs which whilst being fast did not
correlate with the specification, and rise time
at 4µs tended to confirm the measured slew
rate. The overall phase shift as shown in
fig. 10 was unusually small as it needs to be
84
Most portable cassette decks are quite happy
recording the odd pop song.
But give them something truly challenging,
and you soon realize their shortcomings. Fine, if
you're content to be unambitious. But at Nakamichi
we think you should be able to record any sound
you want. Which is the reason why we produced
the Nakamichi 550.
From a mouse
squeak to the triumphant
sounds of Beethoven,
you can record it all on
a Nakamichi 550.
Its peak level
meters have a range of
45dB. Its signal -to -noise
ratio is more than 60dB.
Its microphone inputs
have a.dynamic range
of 125dB.
Wider ranges than
any other portable
cassette deck in the world.
And that's not all.
The 550 is also the only
portable cassette deck
with 3 microphone
inputs. And a tape
end alarm with
pre -set timer.
The only one
too, with a button
that shows how
much of your
cassette you've used.
And Nakamichi's
exclusive record /playback
head. And it's the only one
with a battery life that can give
you up to 15 hours continuous playing.
When you try the Nakamichi 550,
)u'll know why it costs £338 66 including VAT at 121/2 %.
Suddenly, other portable cassette decks look like toys., R
Natural Sound Systems Limited,
}t) Byron Road ,Wealdstone,HarrowMiddlesex,HA3
7TL.Tel: 863 8622.
DUNLAP CLARKE 1000
.
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FREQU
having regard to the lack of high frequency
roll off.
Checking the twin vu meters showed that,
while they were fairly similar to the standard
vu meter, the rise time was too slow with resulting under reading; furthermore, the frequency
response was appalling at high frequencies and
the two meters were different from each other.
In addition the meter attenuator accuracy
was poor -but what is the real use of meters on
a power amplifier anyway; all that is needed is
an indicator for impending overload.
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Summary
Ignoring the fact that the amplifier gave up
the ghost twice and thus escaped a number of
measurements and tortures, it has a very high
power capability which is said to extend down
to 2 ohm loads.
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At no time did it show any tendency to over-
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heat, and unlike many amplifiers its efficiency
remained high at the higher audio frequencies
where so many amplifiers generate a great
amount of heat.
While the measured distortion into resistive
loads was not unduly impressive, this is only
part of the story and the intermodulation performance suggests that the amplifier may well
be good subjectively.
-----
Ç
M
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C:: :::==C::::::=C=:::::=1=:::::=C==::
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2
:-:::ÇÇ:::ÇÇ:::Ç:::ÇÇ_==':::
10
5
50
20
100
200
500
FREQUENCY
The manufacturer makes the following comments
about the prototype review sample:
) The amplifier was not designed as a professional amplifier within the strict meaning of the
word. The company isn't convinced that the
existing circuit is suitable for, perhaps, pa use
whereby the existing protection circuit might
cause problems. However, studio monitoring
applications should encounter no problems.
2) The company is working on an 'early
warning' system offering visual indication of
FIG. 8 Waveform showing recovery from
1 kHz asymmetric tone 50 ms /div
:::
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RESPONSE
I
incipient shutdown conditions.
3) It makes the point that the review unit has
been in service for at least a year prior to the
review. For much of this tine, it had been 'Nell
used and abused' without any apparent failure.
4) It regrets that one channel went wrong fol-
1K
2K
5K
10K
20K
50K
100K
IN Hz
lowed subsequently by the other, after repair of
the first. This should be laid at the door of the
protection circuitry which, on the review model,
had been designed for domestic applications.
That of the smaller 500 and 250 models should
handle any eventuality.
5) The company agrees that the mains switch
on the front panel was bad. Production amplifiers have sleeved connections which cannot
touch the chassis.
6) During the course of the review, a slight
degree of hf instability was noted at low frequencies. This has been remedied resulting in
an improvement to the mid range sound.
7) As delivered to Hugh Ford, the amplifier
quiescent current had been incotrectlr set. On
re- adjustment, it gave even better results.
Broadcast pattern audio JaCkfIeIcIS
from Future Fin Developments
19in Rack Mounting, from one to six rows of 20, 24 or
26 Jacks. The jacks are mounted on a plastic block
which is in turn mounted on a 19in panel. Each row
legend (designation) strip and wire
support bar. The panel is steel, cadmium plated,
chromate passivated and stove enamelled hammer tone silver.
ALSO Audio Patch Cords Microphone Cable
Installation Cable Multiway Cable Post Office and
Rendar Jacks . Cable Markers Lever Keys Linear
Faders
Cannon Connectors Preh Connectors
Switchcraft Connectors .
Tuchel Connectors
is fitted with
a
.
.
.
.
.
.
.
.
.
.
.
.
.
84
*cir
Military Tri -Lock Bayonet
Connectors Audio AttenWahl and Weller
uators
Soldering Irons . PML Microphone Accessories
.
Hellermann Sleeves and Tools Crimp Terminals
Cable Drums AB Engineering Wire Strippers and
DeSolder Guns.
STUDIO SOUND, MARCH 1977
.
.
FUTURE FILM DEVELOPMENTS
Wardour Street, London W1V 3LE
Tel : 01 -437 1892 Telex : 21624
90
Professional Performance
at Popular Prices!
www.americanradiohistory.com
44.410
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of cartridges from Condor
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Manufactured in Holland to an exceedingly high
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Tenorel T2001 ED R.R.P. £10.50 Excl. VAT.
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Ask your local dealer for more details.
Distributed by:- Condor Electronics Ltd.,
100 Coombe Lane. London SW20 OAY. Tel: 01 -946 0033
co
ALLINGTON AUDIO DEVELOPMENTS
794 (A2) Mansfield Road,
VO
Nottingham. Tel. (0602) 624910
Jr
0
The Allen and Heath Broadcast
Feed Forward Delay Limiter.
The only limiter that makes it IMPOSSIBLE for a
transient peak to pass through the unit, without the use
of clipping devices. Included in its design is a
revolutionary bucket brigade integrated circuit. This
delays the main signal path by approximately one
thousandth of a second. Thus gain reduction is fed
forward before there is any increase in the programme
level. The unit can be used with high powered equipment
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studios with effects units.
Try and test one at our demo. studio. Pembroke House,
Campsbourne Road, Hornsey, London N8.
Or, for more information, call Andrew Stirling at
01-340 3291.
FIEAllen
86
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STUDIO SOUND, MARCH
We've got it taped!
Open reel and mono /stereo
cassette duplication at competitive prices
small or large runs.
Printing of cassette labels and insert cards
ask for a quotation!
presents no problems
-
Sound Communication (Publishers) Limited,
Dewsbury, West Yorkshire. Telephone (0924) 469436
1977
www.americanradiohistory.com
8 channel, 2 group Mkt
1000 -ech channel fitted
with corpresso-
The new MXT -1000-
select:
Number. and type of input
channels
Metering and moruitoring
require nnents
Inbuilt power supply or
batteries
Optional `ree sianding
console
A unique system enabling
your own requirements to
be built from standard
equipment
Type of faders
2, 4 group working, or
stereo operation
Manufacturers of
sound systems
and electronics
Optional :-nodules talkback, oscillators, etc
Station Road, Wenden
Saffron Walden
Essex CB114LG
Saffron Walden
(0799) 40888
audix
87
www.americanradiohistory.com
Stereo and 4 Track Mixing Consoles
e 4 -band
equalisation
Low noise circuitry -125 dBm ref inent
e
Low distortion -0.01% typically
Line level and mic level inputs
Line level outputs up to +22 dBm
Prefade listen and talkback optionally
available
Ideal for use
Revox,etc.
with Teac, Further
details
Also available graphic and parametric
equalisers, disc preamp units and
crossovers
contact
ELECTRONICS
Lampas House, Kneesworth St.,
Royston, Herts. 0763 45214
MAIN LONDON
DISTRIBUTORS FOR
RE
I,I H E R
4000 SERIES PORTABLE
Exclusive to
RECORDERS
These
professional
machines
are
widely
open -reel
used
by
REW
the
broadcasting authorities
world over. Available in mono
or stereo, half or quarter track.
Features 4 speeds; A.L.C. We
carry a wide range of accessories
for these machines.
IHER SG630 LOGIC
This features 4 Motor Omega
Loop
Drive, 3 -speed interchangeable Head Block, built -in
Sel Sync and Sound on Sound.
Also many other advanced
professional features.
REW are proud to present the Soundcraftsmen Graphic Equalizer-undoubtedly
the finest unit of its kind for both Hi -Fi and professional use. Each of the stereo
channels is divided into 10 frequency bands, from 20 Hz to 20,480 Hz. Boost
and cut of 12 dB is provided on each band and a gain control adjusts the output
to match any amplifier. The unit has a champagne gold anodised front panel,
enclosed in an attractive wood -grained cabinet. The Soundcraftsmen can be
used as a sophisticated tone control enabling you to highlight individual instruments. Alternatively it can be used to produce a near -perfect flat frequency
response in any domestic conditions by compensating for either poor room
acoustics or various deficiencies in Loudspeakers. Also perfect for equalizing
tape recordings. Send for full literature.
Full range of Equalizers by other leading manufacturers also in stock including
Altec, /VC, BSR, MXR, Technics.
REW Centrepoint, 29 -21 St. Giles High Street, London WC2.
Tel: 01 -240 3066/7.
230 Tottenham Court Road, London WI.
146 Charing Cross Road, London WC2. Tel: 01 -240 3054/5.
Mail orders to: REW House (Dept HFN), 10 -12 High Street,
Colliers Wood, London SW 19. Tel: 01 -540 9684/5/6.
88
STUDIO SOUND, MARCH
1977
www.americanradiohistory.com
REW Centrepoint, 20 -21 St Giles High Street, London WC2.
Tel: 01 -240 3066/7.
146 Charing Cross Road, London WC2. Tel: 01 -240 3064 5.
Mail orders to : Dept SS12, REW House, 10 -12 High Street
Colliers Wood, London SW 19. Tel: 01 -540 9684'5/6.
CALREC
The
LEEVERS -RICH
EQUIPMENT LTD.
Manufacturers of professional recording
equipment for over 25 years cordially
invite you to examine their new range
of Proline Professional recorders at the
PARIS AES Convention -4 MARCH
1
Great
British
Microphone
Chosen by professional
broadcasters, studios and
musicians in 16 countries
Produced by one of
the country's leading
sound desk manufacturers
1977.
made to the same
standards of excellence
,sfv,avz,,
details of our range
and technical spec.
contact us...
For
CaIrec Audio Ltd
Hangingroyd Lane
Hebden Bridge
West Yorkshire HX7 7DD
Telephone (0422 84) 2159
LEEVERS RICH EQUIPMENT LTD.
incorporating Bias Electronics
Trinity Road, Wandsworth,
London SWI8 3SL 01 874 9054 Telex: 923455
319
89
Classified Advertisements
Advertisements for this section must be pre -paid. The rate is 16p per word, minimum £3.20. Box Nos. 40p
Copy and remittance for advertisements in April 1977
extra. Semi -display rates on application.
Issue must reach these offices by 18th February 1977 addressed to: The Advertisement Manager,
Studio Sound, Link Flouse, Dingwall Avenue, Croydon CR9 2TA.
Note: Advertisement copy must be clearly printed in block capitals or typewritten.
Replies to Box Nos. should be addressed to the Advertisement Manager, Studio Sound, Link House, Dingwall
Avenue, Croydon CR9 2TA, and the Box No. quoted on the outside of the envelope. The district after Box
No. indicates its locality. SEX DISCRIMINATION ACT 1975: No Job advertisement which Indicates or
can reasonably be understood as Indicating an intention to discriminate on grounds of sex (e.g. by inviting
applications only from males or only from females) may be accepted, unless (1) the Job is for the purpose of
a private householder or(2) it is in a business employing less than six persons or (3) it is otherwise excepted
from the requirements of the Sex Discrimination Act. A statement must be made at the time the advertisement is placed saying which of the exceptions in the Act is considered to apply.
lin. spools in strong white boxes. Only 16p.
Minimum 50. Quantity discounts. P.T.M.A.,
57 Manor Park Crescent, Edgware, Middx.
C
01 -951 0488.
High Quality Tape Spools
Ex Stock or on Short Delivery
5". 53::7 " in bulk
Plasm Plastics Ltd.
38 Watea Way. Mitcham. Surrey, CR4 4HR
Teiephone:01 -640 0145/9
Plasr
*Cathedral Sound manufacture a professional
standard compressor/limiter module for under
£25.00, mixer modules, and complete mixer
channels. Professional discounts available on
Revox, N.E.A.L., Sennheiser, also MM mixers.
S.A.E. details. Cathedral Sound, Fourways,
Morris Lane, Halsall, Lancs L39 8SX. Tel.
X
Halsall (0704) 840328.
STUDIO FACILITIES
Roger Squire Studios
DJ IMPROVEMENT COURSES RADIO COURSES
JINGLES SERVICE RADIO AUDITION TAPES
55 Charlbert St, London, NW8 6JN. Tel. 01 -722 8111.
-
*J
& B Recordings. Tape to disc. 12in. L.P.
E4. 7M. 45 r.p.m. £1.80. E.P. £2. Pressings
14 Willows
stereo /mono. Tape copying.
X
Avenue, Morden, Surrey. 01 -648 9952.
RAC MIXERS
SPEECH -PLUS RECORDINGS LTD
Specialists in Recording for
Education, Commerce, Industry.
A/V Programmes /Pulsing for Training and
Cassette and Open-reel Duplicating
*Your Tapes to Disc, Mono or Stereo cutting.
Vinylite pressings, Sleeves /Labels. Top profesS.A.E. for photo leaflet.
sional quality.
Deroy Records, "Eastwood ", Cove, Dun X
bartonshire, Scotland.
Sales.
32 PAGES WALK, LONDON SEI
Telephone: 01 -231 0961/2
*Sound News Productions. Britain's oldest
full -time tape /disc cassette transfer service.
O
Direct transfers, pressings for private and for
the trade. Fund -raising advisory service for
Societies, Choirs, Bands, Ferrograph, Grundig,
Philips, Revox equipment promptly serviced.
Tel. 995
18 Blenheim Road, London W.4.
C
1661.
ALSO A SUPERB 8 TRACK RECORDING STUDIO
SPEECH
MUSIC
O
SUN RECORDING SERVICES LTD.
34.36 Crown Strut, Reading B-r k
Tel
FOR SALE -TRADE
MOW
9
0734 - 595647
O
COUNTY RECORDING SERVICE
0
From your tapes we cut master discs, demo discs,
etc.. using our Neumann lathe fitted with the latest
ME /76 UK stereo disc -cutting system.
Telephone Bracknell (0344) 54935.
O
London Road, Binfield, Bracknell, Berks, [7
MM=1==7= LI
England
R
We specialise in recording the spoken word
COMMENTARIES /VOICE -OVERS
AUDITION TAPES
TAPE COPYING and EDITING SERVICE
DJ JINGLES and RADIO
01
-359
9342/7832
masters, any quantity. Studio/mobile Neumann
disc cutter. S.A.E. brochure. 1 Broomfield
Close, Rydes Hill, Guildford. Tel. 0483 61684.
X
STUDIO SOUND, MARCH 1977
4526.
C
Revox A 700's and a selection of spares and
*
SOWTER TYPE
*Fanfare Records. Tape -disc pressings, demo's,
90
C
Laboratory, 01- 346 4469.
*Nagra 111PH068 with Cinema Products
crystal pulse generator and two mic. channels
built in, £695. Document Films, tel. 01 -437
3678
MULTITAP MICROPHONE TRANSFORMER
DANBURY STREET, LONDON NI
Telephone:
fitted, relapping and specials. County Recording Service, London Road, Binfield, Bracknell,
X
Berks. Tel. Bracknell 54935.
* Revox and Teac Sales and Service. Lowest
The Music
prices, immediate delivery.
accessories from stock. Net professional prices
on application. We also offer a prompt and
competent hospital and conversion service
through our Reading office. Call: Chymes of
E
Reading on 0734 -690177 (24 hours).
STUDIO BRZ PRODUCTIONS
34
*Disc -cutting styli for all types of mono and
stereo disc - cutting heads. Heater windings
Primary windings for 600 ohm, 200 ohm and 60 ohm
with Secondary loadingstfrom 2K ohm to 10K ohm.
Frequency response plus /minus }dB 20 Hz to 25 kHz.
Contained in well finished Mumetal box. 33mm diameter by 22mm high, with colour coded end leads, low
distortion. DELIVERY (small quantities) EX STOCK.
HIGHLY COMPETITIVE PRICE. FULL DETAILS ON
REQUEST
E.
1P4
A. SOWTER LTD, Dedham Place, Ipswich,
Telephone 0473 52794
UP
READING UNIVERSITY
TALISMAN THEATRE, KENILWORTH
GRANTHAM HOSPITAL RADIO
RAINHILL HOSPITAL RADIO, LIVERPOOL
WESTMINSTER HOSPITAL RADIO
GEC TELECOMMUNICATIONS
BUSH THEATRE
REVIVAL STUDIO, BIRMINGHAM
AUDIOTECHNIC, DENMARK
Some of the recent customers for RAC Mixers, why not
join them?
RUGBY AUTOMATION CONSULTANTS
19 Freemantle Road, Rugby
Tel 0788-810877
:
i
PEAK PROGRAMME METER
2
A PPM drive circuit with standard performance. Manufactured under licence from the BBC it is based on the
MEI2 /9 but with the addition of our electronic floating
input circuitry which will withstand mains or static
voltages on the signal lines.
ERNEST TURNER PPM movements 642, 643 and TWIN
available from stock with the scalings below.
F REQUENCY
SHIFTER
FOR
REDUCTION
HOWL
STABILIZER
The Stabilizer is a complete box or rack mounting unit
and 10 Hertz allowing optiproviding shifts between
misation of the shift for the acoustics and sound sources
involved.
I
F 5Hz FIXED SHIFT CIRCUIT BOARDS as WW
July 1973 article but improved noise level.
Small enough to be built inside the cabinets of many
amplifiers. DESIGNER APPROVED.
Complete kit and board E28. Board built and aligned E36.
Including rosir and mains transformer.
SURREY ELECTRONICS
The Forge, Lucks Green, Cranleigh,
Surrey GU6 7BG. (STD 04866) 5997
CASH WITH ORDER less 5% UK POST FREE ADD VAT.
at 8%.
FOR SALE-TRADE
SERVICES
(Continued)
BROADCAST
CARTRIDGE MACHINES
for sale orlong/short term hire. Record/
playback and playback only from stock.
Audiopak's also available.
Tel: Herongate
(027787) 531
WE CARE FOR OUR REVOXESWHY NOT LET US CARE FOR YOURS?
We can do anything you can dream up for the A77 within reason, and without
detriment to the normal performance of the A77, such as:
I Any speed from 30 i.p.s. down to {-} i.p.s. without any of the usual problems.
2 Improving specifications to the most amazing standards for the professional
user
Pause
3
control.
inputs with or without phantom feed up to 21 volts.
Cannon input and output.
6 RAPID SERVICE.
WE PROVIDE IMMEDIATE SERVICE TO THOSE WHO URGENTLY REQUIRE
THEIR REVOXES.
4 Balanced line mic
:
SALE
CONTENTS OF 16 TRACK STUDIO
including: Tape recorders, Mixing consoles, Microphones, Reverberation devices, Dolbys, Compressor / Limiters,
Delay units, Grand piano, Microphone
stands, etc.
Viewing by appointment with Malcolm
Jackson, The Studios,
Rickmansworth,
Herts, England
Tel. Rickmansworth 09237 -72351
Telex 262284 Ambsdr G
OWN A MINI NAGRA SN
Then realise its full potential
for the first time with the
DOCUMENT
SQN
?
CONTROL UNIT
Illustrated brochure available from
sole manufacturer:
-
I)OCUMENT GROUP LONDON Ltd.
THIRD FLOOR, 8 -12, BROADWICK ST.,
LONDON, W1V 1FH.
Telephone: 01 -437 4526/7.
Cables: FILMDOC LONDON W1 England.
SOWTER TRANSFORMERS
FOR SOUND RECORDING AND REPRODUCING EQUIPMENT
We are suppliers to many well -known companies,
studios and broadcasting authorities and were established in 1941. Early deliveries. Competitive prices.
Large or small quantities. Let us quote.
E.
A. SOWTER LTD.
Transformer Manufacturers and Designers
7
Dedham Place, Fore Street, Ipswich IP4 IJP
5
Radio Recordings
*R. Beaumont, specialist audio repairs and
Philips VCR service, 21 Southway, Ilkley,
West Yorkshire. Tel. 094-33 2026.
X
*Tape Copying Service. Open reel and cassette
available. The Music Laboratory, 01- 3464469.
C
WATFORD
I49B
St
AM'
ii
AlW
WOLLENSAK 2770AV
\
Alg
\
CASSETTE FAST -COPIER
SCS Appointed Main Dealers
%
Personal Service
Maintenance
Cassette Fast- Copying -Short or Long Runs
Telephone enquiries welcome
\
SOUND CASSETTE SERVICE
\
Demonstrations
PO Box 2, Gerrards Cross, Bucks SL9 8EG
Tel: 02813 84409
II
STUDIO EQUIPMENT
SERVICES
FOR HIRE
Technical services for studio
sound equipment.
Test tapes up to 2 inch
REVOX
We supply REVOX, UHER,
BRENEL, TASCAM, TEAC
QUAD 303, REVOX A78,
SPENDOR and GALE speakers, mic stands. AKG mikes
01
-200 1229
A77 (HS standard
NAB CCIR vari- pitch, varispeed etc.).
AKG
BX20,
etc.
Radio Recordings
Telephone:
High speed cassette copying and
mastering service, mono and stereo.
We specialise in small quantities as well
as long runs.
MORARD SOUND PRODUCTIONS
THORNTON HEATH, SURREY
TELEPHONE
01
-689 7424
01
-586 0064
CASSETTE DUPLICATING
from Reel or Cassette Master.
Mono or Stereo, Speech or Music.
Long or Short runs, superb quality.
EDUCATIONAL TAPES LTD, Dept 5.S.
P.O. Box 4, Hemel Hempstead, Herts.
Tel: Hemel Hempstead (STD CODE 0442) 68484.
REVOX
SERVICE CENTRE
*
*
*
47988 ; *
* Automatic
* Varispeed/varipitch.
Watford,
,..,..
-iiL11:1
-s
-->' - i---s-
All Studio Equipment bought and sold.
See our advertisement on page 18
i
\
Telephone 0473 52794
TRAD
Tel. No. 01-586 0064
WE CAN SUPPLY A RESULT SHEET ON REQUEST FOR ANY MACHINE
WE HAVE REPAIRED OR MODIFIED.
Service and overhaul.
High speed conversions.
Head changes.
Self sync.
Double Tracking.
Albans Road,
Herts
Tel: Watford 47988
01 -346
4469
FOR SALE -PRIVATE
*Sale.
console.
18 input, 8 output, 16 monitor mini
As new, used only 3 months hire to
one studio. One year guarantee and service.
£4,380. Channel direct O /Ps. Full EQ and Hi
and Lo filters, PFL. Insert points in channels
and groups. 8 groups normalled to tracks 1 -8,
jackable to any of 16 tracks. 16T monitoring.
Remix facility for 2T. 2 channel aux. sends
plus one monitor aux. XLR's, mic, line and
all inputs- G.P.O. jacks elsewhere.
48v
phantom power. Raindirk Ltd., tel. 036632165.
C
91
FOR SALE
-
PRIVATE
STUDIO EQUIPMENT SERVICES
(Continued)
STILL REQUIRE
8 track machines
2" 16 track machine
I"
M56 OWNERS
Unused,
-SAVE
£750!
Ian Downs
head block for sale. Fully
guaranteed. Only £1850
16-track
01 -200
1229
P.T.M.A. LTD
Manor
Middlesex
57
Park
Edgware,
Crescent,
01 -951
similar models. Replies to Apex Electrical Co.
Ltd., 1/3 St. Michans Street, Dublin 7.
C
*Wanted. Teac A 3300S2T, Revox H1102 or
Must work perfectly. Also
Sony 756 -2.
wanted: DBX AI -22. Coleford (Glos) 3503
evenings.
C
SITUATIONS VACANT
0488
*Teac 4 Track sel sync 3340. Brenell -} track
stereo. Teac Reverb stereo unit. Pioneer
Reverb Stereo Unit, Millbank stereo 8 into 2
mixer with e.q. 50 -way G.P.O. spec patch
panel, all equipment built into custom-built
desk -type unit. £2700 o.n.o. Tel. 01 -654 5631
C
after 6 p.m.
Ampex tape recorder Model
*For sale.
MM1I00 eight track, one year old, for lire
For information contact: G7
10,000,000.
Recording Studio, Via Barbaroux N.15, 10122
C
Torino, Italy. Telephone 011 -510 560.
*Alice 6/2 Desk (Custom). F/B, S/S outputs,
A -B monitoring, separate power supply, multi core, case, £300. JBL 2125 monitors £500.
AKGmicrophones,
headphones, studio reverberation units and
hi fidelity stereo cartridges are the major product choice of the
professional_and consumer audio markets.
Experienced Sales Executives are wanted to drive forward our new
expansion programme.
Cecil Woolf, Managing Director,
AKG Equipment Ltd.,
182
*Synthesize! EMI VCS3 plus duophonic
keyboard (with portamento!) plus Sequencer
Best offer over £1000. Buyer
C
2289.
4S plus accessories. Almost new.
S.A.E. Harry Rix, 38 St. Vincent
to:
Please apply
C
Tel. 01 -520 8363.
*Revox's urgently wanted. Top prices paid.
The Music Laboratory, 01 -346 4469.
C
*Wanted to purchase: King cassette winding
machine and Tellex duplicating machine or
:4 Campden Hill Road, Kensington,
London W8 7AS. 01 -229 3695'6.
32. All perfect.
01 -274
collect.
*Nagra
Cheap.
Avenue, Woodlands, Doncaster, South YorkC
shire DN6 7TY.
ENGINEER
RANK KALEE
Wow and Flutter Meter type 1740 in
perfect working order complete with
operating instruction book and circuit
diagrams. £95.00.
Telephone
01
DISC CUTTING
-568 9222, ext 349
RCA Records
have
a
vacancy for an experienced
disc-cutting engineer.
Equipment includes Neumann lathes and Ortofon cutting systems.
WANTED
*All Nagra equipment urgently required for
cash. J. J Francis (W.G.) Ltd., Manwood
House, Matching Green, Harlow, Essex CM17
X
ORS. Tel. Matching 476.
*Teac A3340(S) urgently required. Top prices
paid. The Music Laboratory. Tel. 01 -346
Excellent basic salary plus opportunity for good
Please write to: Personnel
Manager, RCA Records Ltd, 50 Curzon Street,
London W Y 8EU.
overtime earnings.
ncn
I
C
4469.
*Westrex l0A pickup cartridge and Good -
mans AXIOM 80 speakers. Also PX4, PX25,
STC 4300B triodes. Box No. 753 c/o STUDIO
C
SOUND.
It helps
STUDIO SOUND
when replying to
ADVERTISEMENTS
STUDIO SOUND, MARCH
Project Manager
Studio
to mention
92
Sales
1977
Osram GEC Ltd, leading manufacturers of lamps for film and TV studios, wish to
appoint a Project Manager. The ideal person will feel at home with studio engineers, have a working knowledge of studio lighting and be happy to spend time
abroad developing sales.
The job, which is open to both men and women, is based at the Wembley Head
Office and a company car is supplied.
If you are looking for a new way of making use of your valuable experience contact
John Pepper, Osram GEC Ltd, PO Box 17, East Lane, Wembley, Middlesex.
Telephone 01 -904 4321.
Inner London Education Authority
SITUATIONS VACANT
(continued)
CINE ANIMATION TECHNICIAN
Grade 5
required at Central School of Art and Design, Southampton Row, WCI, in the Department of Graphic
Design. To control the operating of a small but productive cine- animation section, with some lively and
interesting films to its credit; the unit is largely
concerned with postgraduate level work.
London College of Furniture
Electronics for
Musical Instrument
Technology
Ability to handle sound production, recording and
dubbing is essential, together with experience in
working with 16 mm film and an interest in animation.
Applicants should have at least HNC, HND, Advanced
City & Guilds or equivalent qualifications and at least
eight years' experience (including trainirg period).
Salary scale 6275143207
6465 London Weighting
plus individual earnings supplement in accordance
with the Government's Incomes Policy.
Further particulars and application form available from
the
SENIOR ADMINISTRATIVE
OFFICER
A full -time three year course is offered in those aspects of
electronics related to the design, building and repair of all
at this School.
Telephone 01 -405 1825, returnable within two weeks
of this advertisement appearing.
types of equipment associated with music.
Students will be encouraged to involve themselves in project
work in the fields of acoustics, group amplification, electronic
organs, synthesizer design, etc.
Prospective students should have some knowledge of electronics or some basic science and mathematics at 'O' level
GCE or the equivalent.
*Maintenance engineer required to work
within a West London film dubbing complex.
Duties to include construction and installation
of all types of recording equipment. Box No.
754 c/o STUDIO SOUND (London).
C
il
*Trident Studios require experienced Mainten-
ance Engineer. Salary negotiable. Ring Sarah
For details apply to: Department of Musical
aInstrument Technology,
London College of Furniture,
41 -71 Commercial Road, London El ILA
Telephone: 01 -247 1953
C
01 -734 9901.
Industrial
Tape Applications require
Electronic and Electro- Mechanical engineer
for design and development of equipment
relating to the recording industry. An attractive salary is offered to the successful applicant who will be required to see projects
right through to production.
cadac
Expansion within the company dictates the
need for a new appointment.
MARKETING MANAGER
Please phone 01 -485 6162'7833
We are looking for a person with
a track record in the professional,
audio, studio field.
SHEFFIELD SOUND CENTRE
SPECIALISTS IN
HI -FI
Main agents for Teac, Tascam, AR, Uher, Dokorder,
Revox, Spendor, JBL, Dahlquist, Tannoy, Lowther,
Ferrograph, Marantz, Bic Technics, Quad, Armstrong,
Sony, Nagra, IMF, Dbx, Otari, and many more.
Competitive prices, terms, part exchange
101a and 107 ECCLESALL
Tel: 0742 23365
ROAD
Please mark your application.
private and confidential for the
attention of Jim La -Haye,
Director.
CADAC (London) Ltd.
141 Lower Luton Road.
Harpenden,
Herts. AL5 5EL.
(STD 05827) 64351
Telex 826323
93
INDEX TO DISPLAY ADVERTISERS
N
F
A
Acousmat Apollo ..
AKG Equipment Ltd.
Alice (Stancoil) Ltd.
Allen & Heath Ltd.
Allington
Amek
Ampex
A.P. Ltd.
A.P.R.S.
Audio & Design Recording Ltd...
..
Audio Developments
Audix
Avcom
B
Bauch Ltd.
Beyer Dynamics
B.G.W.
Brenell
.
75
79
10
86
86
67
24
Feldon Audio Ltd.
Freedmans ..
Future Film Developments
10
6
84
6
Grahams Electronics
Griffiths Hansen Ltd.
19
63
87
69
55
8
30
¡FC
77
89
.,
..
17
16
86
D
Dolby Laboratories
73
23
20, 72
..
..
Exposure Electronics
22
5
52,53
International Audio
ITA
.
11,12,13,15
.
60
8
..
81
Radford Hi Fi
Raindirk
REW
..
..
..
16
R
29
L
Leevers Rich
Lyrec
89
45
M
Macinnes Laboratories
Magnetic Tapes Ltd.
M.C.I.
Midas
M illbank Electronics
M.M. Electronics
Music Laboratories Ltd. ..
Mustang Communications
.
Scenic Sounds
Schlumberger
Scully
Shure Ltd. ..
Sound Communication
27
47
39
.
.
9
86
Soundcraft ..
Squires, Roger
Studio Equipment Services
Surrey Electronics ..
T
43, 51
..
..
.
.
..
..
.
..
8
61
IBC
75
88
S
.
K
.
E
85
.
Otari
Quad
H.H. Electronics ..
Hammond, C. E. ..
Hampstead Hi Fi ..
Hayden Laboratories
Klark Teknik
C
Cadac (London) Ltd.
C.A.E. Ltd.. .
Calrec
Cetec Audio
Charlesfield Audio ..
..
Condor
..
.
Q
H
57, 59
..
25
Neve
16
I
..
83
6
..
..
O
G
35
56
..
Natural Sound Systems
N.E.A.L.
Trad ..
..
Trident Audio Dev Ltd.
Turner Electronic Ind. Ltd.
Tweed Audio
..
.
31
4
16
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Ward Beck Systems
Wilmot Breeden ..
75
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21,65
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CLASSIFIED ADVERTISEMENTS ORDER FORM
Please use this coupon for your private sales and wants. Rates 16p per word. Minimum f3.20. Box Nos. 40p extra.
To: Studio Sound, Classified Advertisements Dept., Link House, Dingwall Avenue, Croydon CR9 2TA. Please
insertion /s under the heading
publish the advertisement indicated below for
Cheque /P.O. enclosed £
Name
Is a
Address
Box No. required Yes /No.
If no, please include
remittance to cover name and address and /or Tel. No.
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write
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Link House Publications Ltd., Registered in England No. 96948. Registered Office: 10/12 South Crescent, Store Street, London WC1E 7BG.
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Published by Link House Publications Limited on behalf of the proprietors, Link House Holdings Limited, 10 -12 South Crescent, Store Street, London W.C.1, and Printed by
Arthurs Press Limited, Woodchester, Stroud, Glos. GL5 5PB.
Suf
musícíons
Beach Boys, Eluis Presley, Supertramp,
Pink Floyd, Elton John, Chicago, YES.
sound hire:
Sounds West u.s.a. Entec u.K.& U.S n. Delicate Acoustics u.s.a.
Clair Brothers u.s.A. Britannia Row u.K. Audio Analysts cafADA
54-56 Stanhope Street, London rum 3EX. Tel: 01-388-2060
Louis De Potesto, RRC, S.PR.L Rue M. Decuyper, 134, 12C C Brussells, Belgium. Te 7-71-30-63
Ward -Beck consoles stand apart.
From the largest custom installation
to the smallest stock portable, WardBeck consoles stand apart.
Classic styling, operational
ease and trendsetting technology
combine to make Ward- Beck's 460
Series a very special experience.
Every performance brings the
reassurance that Ward -Beck is
the professional choice.
(wes)
Tomorrow's Technology Today.
Ward -Beck Systems Ltd., 841 Progress Avenue, Scarborough, Ontario, Canada M1H 2X4.
Telephone (416) 438-6550. Telex 06- 23469.
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