PORTABLE - American Radio History

PORTABLE - American Radio History
ECB-280
AMPLIFIERS
Pages A3 -A50
CONTROL
Pages A101 -A111
POWER
SUPPLIES
Pages A201 -A205
SHELVES AND
CABINETRY
Pages A301 -A317
MICROPHONES
& ACCESSORIES
Pages A401 -A402
STUDIO &
PORTABLE
EQUIPMENT
SPEAKERS &
ACCESSORIES
Pages A501 -A 504
TRANSCRIPTION
Pages A601 -A602
TRANSFORMERS
Pages A701 -A705
DEFENSE ELECTRONICS DIVISION
TECHNICAL PRODUCTS OPERATION
GENERAL
AUXILIARY
ELECTRIC
SYRACUSE, NEW YORK
www.americanradiohistory.com
EQUIPMENT
Pages A801 -A808
AUDIO
Contents
Contents
Page A
1
AMPLIFIERS
Broadcast Amplifiers, Ratings and Terminology
Plug -in Uni -level Amplifier, Type BA -9 -A
Uni -level Amplifier, Type BA -9 -B
Transistor Cue Talkback Amplifier, Type BA -28 -A
A3
A7
Al
1
A15
Audiomatic Limiting Amplifier, Type BA -7 -A
Transistor Monitor Amplifier, Type BA -24 -A
Transistor Monitor Amplifier, Type BA -34 -A
A -c Powered Program Monitor Amplifier, Type BA -14 -A
A17
A23
A25
A29
Pre -amplifier, Type BA -20 -A
Transistor Pre -amplifier Module, Type BA -21 -A
Plug -in Pre -amplifier, Type BA -1 -H
Transistor Plug -in Pre -amplifier, Type BA -25 -B
A33
A35
A37
A39
Plug -in Program Monitoring Amplifier, Type BA -12 -C
Transistor Program Amplifier, Type BA -22 -A
Plug -in Uni -level Pre -amplifier, Type BA -15 -A
Microphone Pre -amplifier, Type BA -30 -A
Equalized Monaural Stereo Transcription Pre -amplifier, Type BA -23 -A
A41
A43
A45
A47
A49
CONTROL
Transistorized Portable Amplifier, Type BA -26 -A
Transistorized Audio Console, Type BC -12 -A
Bridging Volume Control, Type FA -35 -G
A101
A105
Al
POWER SUPPLIES
Plug -in Power Supply, Type BP -10 -B
Transistor Power Supply (25- volt), Type BP -20 -A (Regulated)
Transistor Power Supply (50 25- volt), Type BP -21 -A (Regulated)
11
A201
A203
A205
SHELVES AND CABINETRY
Broadcast Shelves, Types FA -23 -B, FA -23 -C, and FA -46 -A
Broadcast Shelf, Type FA -48 -Al
Cabinet Rack, Type PR -1 -A and Accessory Items
Control Console Base Cabinets, Types PR -16 -B C, PR -17 -A
A301
A305
A307
A313
MICROPHONES AND ACCESSORIES
Microphone Cable, Type
FA -15 -A, Plugs, Types FA -16 -A, -B, and Receptacle, Type FA -16 -C
SPEAKERS AND ACCESSORIES
Monitoring and Wall Speakers, Types
FS -1 -B
Speakers, Types 850, 1201A, and 1203A
and
FS -2 -B
A401
A501
..
A503
TRANSCRIPTION
Transcription Equalizer, Type FA -12 -B
A601
TRANSFORMERS
Line -to -Line Transformer, Type FA -40 -B
Bridging -to -Line Transformer, Type FA -41 -C
Line -to -Voice Coil Transformer, Type FA -42 -A
A701
A703
A705
AUXILIARY EQUIPMENT
Interconnecting Cables, Types FA -19 -J, FA -19 -M, and FA -19 -R
Equalizer Panel, Type FA -14 -A
Equalizer Unit, Type FA -14 -B
Program Level Indicator Panel, Type FA-1-A, Switch and Fuse Panel, Type FA -4 -A
Sound Effects Filter Panel, Type FA -18 -A
Jack Strip, Type FA -2 -A
Jack Panels, Types FA -3 -A, FA -3 -B, and FA -3 -C, and Patch Cords, Types FA -7 -A, FA -7 -B, and FA -7 -C
.
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A801
A803
A804
A805
A806
A807
A808
AUDIO
Amplifiers
Broadcast Amplifiers
Page A3
Ratings and Terminology
General Electric broadcast amplifiers operate over a
frequency range of at least 50 to 15,000 cycles and will
deliver their full rated power throughout this range.
The distortion and noise are reduced to values suitable
for the most exacting service.
Much care has been taken in the design of these
amplifiers to assure maximum reliability of operation
as well as convenience for servicing.
The ratings given throughout this catalog use the
following gain and level ratings:
db- refers to gain or loss
dbm- single- frequency, sine wave power referred to
1 milliwatt
(dbm =10 log P)
0.001
Program level as read on a standard VU
meter. Since program material is of a complex
and transient nature, the VU meter indicates
a level considerably under the instantaneous
peak program level. In practical usage the
amplifier dbm rating should exceed the VU
level to be transmitted by at least 10 db.
The chart showing "Characteristics of G -E Broadcast Audio Amplifiers" lists the General Electric name
and uses for each amplifier.
The following uses are defined in EIA Standard
TR -105B dated November 1949:
VU
PRELIMINARY AMPLIFIER
A preliminary amplifier operates from a microphone
or other low -level source. A preliminary amplifier
amplifies the microphone output or other signal to a
level that can be fed into a subsequent circuit without
the signal -to -noise ratio being degraded.
BOOSTER AMPLIFIER
A booster amplifier is connected in the main -pro-
gram line between the preliminary amplifier and the
program amplifier.
DISCUSSION OF GAIN RATINGS
TRANSFORMER
UNLOADED -INPUT
(40 -db
gain)
When the full generated voltage of a microphone,
turntable pickup, or similar device is applied to the
input terminals of the amplifier which it is feeding, the
operating conditions are referred to as those of an unloaded -input transformer since no resistance loading of
the transformer, either primary or secondary, is used.
Under these conditions the highest signal -to -noise
ratio of a microphone -amplifier combination is obtained because the amplifier does not load the microphone.
Operating with an unloaded -input transformer, as
explained above, a typical pre -amplifier has a gain of
40 db. This gain is defined as the ratio of "power delivered to the load" to the "power which would be
delivered to the load" if the pre -amplifier were replaced by an ideal transformer connected to match
the load and source impedance. The gain is determined as follows: (See Fig. 1 for diagram.)
A source resistance (Rs) fed by an oscillator is connected to a load resistance (R1) of equal value. The
oscillator output is adjusted until the power dissipated
in R1 is -40 dbm, as indicated by the power measuring instrument P,. The output voltage of the oscillator,
as indicated by voltmeter V is recorded, RL is then disconnected for Rs and the oscillator, and the pre- amplifier is connected in place of RL. A tap on the input
transformer of the amplifier is used which is equal to
the value of Rs (150 -ohm tap for 150 -ohm Rs). The
output of the oscillator, as indicated by voltmeter V,
is held constant at the value previously recorded. The
resulting output as indicated by P2 which the amplifier
will deliver to its proper load resistor Ra is zero dbm.
Thus the gain of the amplifier is 40 db.
PROGRAM AMPLIFIER
A program amplifier is connected in the main program channel and is capable of delivering standard
output level.*
BRIDGING AMPLIFIER
A bridging amplifier internal input impedance is
such that it may be connected across a circuit without
appreciably affecting the circuit performance in any
respect. The bridging amplifier operates into program
circuits or similar loads.
MONITORING AMPLIFIER
A monitoring amplifier is connected to a program
circuit to provide a means of checking the program.
The term "Program Amplifier" is now used in place
of the nonstandard term "Line Amplifier" or "Main
Amplifier." The term "Bridging Amplifier" is now
used in place of "Isolation Amplifier."
+18 dbm to lines or +12 dbm to transmitters.
PRE
Fig.
-AMPLIFIE
1
MATCHING INPUT (34 -db gain)
When the input circuit of an amplifier constitutes a
resistive load equal in value to the impedance of the
source feeding it, the amplifier is said to have a matching input. Under these conditions the voltage at the
terminals of the input transformer of the amplifier is
only one half the voltage generated by the source. This
constitutes a 6 -db drop in the voltage input to the
amplifier which effectively produces a 6 -db decrease in
amplifier gain as compared with the gain obtained
with unloaded -input transformer operation. Thus, the
gain of the amplifier with matching input is 34 db.
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Amplifiers
Broadcast Amplifiers
Page A4
Ratings and Terminology
BRIDGING INPUT (10-db gain)
When an amplifier or similar low- impedance device
is connected across a low- impedance line in such a way
that only a small fraction of the energy in the line
(insufficient to affect the operation of the line) is
diverted into the amplifier, the amplifier is said to
employ a bridging input. This is accomplished by
stepping up the input impedance of the amplifier (to
10,000 or 20,000 ohms, for example) so that in connecting it across the low- impedance line (0 -1000
ohms) it has negligible effect.
10.000
TI
J1.12
1/7 W
PRE -AMPLIFIER
600
10.000
OHMS
1/2 W
600 OHMS
UNBALANCED
INPUT
BRIDGING
INPUT
31
ó
4700.E
¡
.M/1.
12
n
10.000
600
1/2 W
OHMS
BRIDGING
INPUT
4700.1
2
I
PRE- AMPLIFIER
n-B
11
J1,11
Îs
I
Fig. 3.
TI
11.12
1/2 W
-------- ---
600 OHMS
BALANCED
INPUT
Used as a bridging amplifier, the pre -amplifier has a
gain of 10 db, where the gain is defined as the ratio of
the "power (P1) in the 600 -ohm line terminating resistance (RL) to the output power (P2) of the amplifier";
that is GAIN (db) = log P2÷ P1. Fig. 4 shows the circuit employed in measuring gain with bridging input.
W
3 00
0
T000
PRE -AMPLIFIER
Fig. 2.
OSCILLATOR
Figs. 2 and 3 show the circuits of resistive pads
either of which, when connected to the 600 -ohm input
terminals of a typical pre -amplifier, converts the 600 ohm unloaded transformer input to a 10,000 -ohm
resistive -input impedance. With such a pad the amplifier may be "bridged" directly across a low- impedance
line.
I
- -
SHORT
600
o
0
LINE
'A
300
R. (TOTAL).
R,
R,
SOURCE
I
4700.0BRIDGING
CIRCUIT
600 A
Ro
RESISTANCE
LINE TERMINATING
RESISTANCE
Fig. 4.
:
AMPLIFIER LOAD RESISTANCE
P,
POWER
P=
POWER
IN
IN
R,
Ro
AUDIO
Amplifiers
Broadcast Amplifiers
Page AS
Ratings and Terminology
CHARACTERISTICS OF G -E BROADCAST AUDIO AMPLIFIERS
Type No.
Use
Name
BA -20 -A
Pre -amplifier
(Plug -in)
Microphone
Pre-amplifier
Booster
BA -21 -A
BA -22 -A
Program Amplifier
(Plug -in)
M-23-A
Equalized
Stereo /Monaural
Transcription
Preamplifier
BA-24 -A
Monitor
Amplifier
BA -25 -A
Pre -amplifier
Microphone
Impedance
(Ohms)
(Ohms)
40
or
50
50/150/250/600
600 Unbalanced
40
or
50
50/150/250/600
Output
Gain
(DB)
(DB)
-35 max
50 db gain
-25 max
40 db gain
-10
-35 max
50 db gain
-25 max
40 db gain
- 10
-22
+24
PGM Amplifier
BD'G Amplifier
1 SO. Amplifier
(matching)
Two channel
Transcription
High impedance
Pre -amplifier
Source
Impedance
Input
(DBM)
Cartridge
-10
75
Portable
Amplifier
BA -28 -A
Cue /TB Amplifier
BA -30.A
Microphone
PI e- amplifier
Balanced or
Unbalanced
50/150/250/600
Balanced or
Unbalanced
40
High impedance
at
600 Unbalanced
150/600
Balanced or
Unbalanced
150/600
Balanced or
Unbalanced
1000
Self
Contained
Gain Control
Monitor or
Distribution
Amplifier
-25 max
(matching)
Microphone
Pre- amplifier
-22 Max
Matching
+33
80
-25
Balanced or
Unbalanced
+18
Remote pickups. Auxiliary
studio opplications
to -level inputs.
after
0 max
4 db
For cue, TB
-22 max
matching
and to -level
monitor
applications
Microphone
Pre -amplifier
Mounted at
Microphone
Watt
BA -34 -A
10
Monitor
Amplifier
Monitor
Amplifier
max
hi -level
input
-
14 max
20 DB Gain
-24 man
30 DB Gain
-34 max
40 DB Gain
-50 max
56 DB Gain
-30
max
Matching
50/150/250/600
46
+18
90
pad
+27
+7
150/250/600
8/150/600
Balanced or
Unbalanced
8 ma -25 -v use
BP -20 -A or
25 -v Section
of BP -21 -A
panel module
160 ma -50 -v
Plug -in
d -c use
chassis
Accessory
may be added
Self -contained
20
or
30
or
Accessory
may be added
50 150 250 600
Balanced or
Unbalanced
150/600
Four mic mixers,
Balanced or
Unbalanced
150 or 600
Unbalanced
master, one hilevel set level
Accessory
control may
be added
None
Plug -in fiber
glass printed
Plug -in front
use
18 ma -25 -v use
BP -20 -A or
T. T. Motor
Board
Mounting
Plug -in
chassis
Plug -in
chassis
95 -135 -v
50/60 cycles
self- contained
plus batteries
Enclosed in
160 ma -50 -v
Plug -in
chassis
d -c use
BP -21
portable
aluminum
case
-A
10 ma -15 to
25 -v d -c
22 -V battery
or 25 -v d -c
Mounts in
MIC Line
Between
P3 Connectors
supply
or
56
100
-25 -v
25 -v Section
of BP -21 -A
40
+40
380 ma max
BP -20 -A
be added
ISO or 600
Unbalanced
117 or 230
VAC 50 60
Selfcontained
Accessory may
150/600
25 -v Section
of BP -21 -A
CPS
150 /600
Balanced or
Unbalanced
BP -20 -A or
BP -21 -A
Balanced or
Unbalanced
50 150 250 600
Balanced or
Unbalanced
Type
of
Mounting
Gain control
and mixer key
included
control
75
PP Y
8 ma -25 -v use
Balanced or
Unbalanced
50
Power
Interstage
Gain control
may be added
CPS
Booster
BA -26 -A
Balanced or
Unbalanced
Load
50/150/250/600
Balanced or
Unbalanced
8/150/600
Balanced or
Unbalanced
Gain control
included
117 or 230
VAC 50/60
CPS self -
contained
regulated
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Plug -in
chassis
Amplifiers
Broadcast Amplifiers
Page A6
Ratings and Terminology
VOLUME LEVEL TO POWER AND VOLTAGE CONVERSION TABLE
Reference Level
0
dbm
milliwatt, 600 ohms
1
Milliwatls
Volts
0.000001
.000010
.000100
0.0007746
.002449
.007746
DBM
60
-50
-40
-3u
_2G
-1t,
.02449
.07746
.2449
.7746
.001
.010
0.100
.000
1
0
DIM
Volts
Wafts
0.7746
0.001000
.002512
.006310
4
8
!-
+10
2.449
7.746
24.49
77.46
.01000
.1000
1.000
10.00
o
i-
.228
1.946
1
4-20
t-30
+40
RESISTIVE PADS
R,
R
For impedances
other than 600 ohms,
multiply all resistors
by Factor
PAD
T
Zx
600
600 ohms
2,,,,.
R,
2
18
36
68
3
100
4
5
130
160
200
'h
1
6
7
8
9
10
11
12
13
14
15
10000
5100
2700
1800
R.
R,
51
16
17
18
19
430
470
470
470
200
180
150
130
220
220
240
240
68
20
82
22
24
26
510
510
510
560
120
100
240
270
270
270
560
560
560
560
47
39
30
24
270
270
300
300
560
560
560
18
15
12
300
300
300
8.2
18
36
220
1200
1000
820
680
100
110
270
300
300
330
560
470
430
360
130
150
160
160
28
30
32
360
390
390
430
330
270
240
220
180
200
200
200
36
38
34
40
0
-l0
ó -20
+40
DBM
10
ogto
30
0.001
1111111111111111111
II
111111:1111!II111111
60
50
20 111111111111111111111111111111111111111
-40
l::1111l1:11111!
10 11111111,1111111111111111111111111
%im1Ì mo111111ii11111 Ì==111111Q1=1111Ì
6db 10
3db -6
0
0.001
10'I
lo's
aol
10-7
QI
lo'5
10's
Power in watts
DB VS. RATIO
70
-30
-50
i0=1iiwi11
fMINfe>=111_ft
80
DBM VS. WATTS
° 40
ó 30
20
Y
--I
50
lo
loo
10'4
l0-s
75
62
1i/_
p
Ar
IMrl
EIA resistor values nearest to the exact values are given.
*
R,
R,
R
R_
PAD
EIA Resistor Values *
Lois in DB
EIA Resistor Values
Loss in DB
H
R,
Current
EN or vo toge
.
MPW
t>/
NIMl1
_
I111111
11i
im-e1momP.
O
4
se
2
10
4
68
2
100
Rogo
4
68
1,000
2
4
68
10,000
AUDIO
Amplifiers
Plug -in Uni -level Amplifier
Page A7
Type BA -9 -A
Plug -in uni -level amplifier, Type BA-9 -A
FEATURES
Versatile
Permits unattended remote audio operation
This amplifier used on an incoming remote line
automatically controls level variations from an unattended remote amplifier. (See Fig. 3 Typical
Applications)
Controls level differences between two or more program
sources
Level differences automatically controlled between:
(a) Turntables and /or projector outputs
(b) Network incoming signal (when properly
padded) and projectors, turntables, or announce mike pre -amp
May be used as a program line compressor
May be used as an automatic master gain control for
program line
Typical Applications)
(See Fig.
May be used as a microwave input audio control
(See Fig. 4 Typical Applications)
May be used as an expander -compressor amplifier
With average program material set for 15 db of gain
reduction, output will be compressed for incoming
signals exceeding 15 db and expanded for signals
below 15 db.
May be used as an automatic fader control
(See Fig. 2 Typical Applications)
May be used as a straight program amplifier with or
1
without level control
Removal of one tube disables automatic level control and permits use as a normal program amplifier
Physically and functionally interchangeable with
Type BA -12 -C plug -in program /monitor amplifier
when used for program purposes
Can be used in Type BC -11 -A audio console in place of
the program amplifier to provide automatic master gain
control for the console
Small, compact, plug -in construction
(a) Compact design permits four units to be mounted
in seven inches
of rack space
Plug -in construction speeds maintenance
Used as a peak level control
Amplifier will operate over a 30 db range with only a
10 db change in output
(b)
Used as an average level control device
Amplifier will operate over a 30 db range of input level
with only a 10 db change in output level
Variable threshold level
Amplifier will operate with the threshold level set at
any output between
1
19 dbm and -f 30 dbm.
Average program /dual recover switch
This switch permits use of amplifier as an
control or as a peak level control
Dual time constant eliminates program
Recovery time
material
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is
an automatic
average level
"pumping"
function of program
Amplifiers
Page A8
Plug -in Uni -level Amplifier
Type BA -9 -A
WHERE TO USE
The General Electric Type BA -9 -A plug -in uni -level
amplifier is an automatic level - control unit designed to
automatically control variations in audio program
level. This compact, plug -in unit replaces or may be
used in addition to the Type BA -12 -C plug -in program /monitoring amplifier when the latter is used as a
program amplifier.
The Type BA -9 -A uni -level amplifier may be used
as an average level - control device or as a peak level control amplifier.
Maximums of up to 30 db in program variations
may be successfully controlled by this amplifier. Such
variations are sometimes encountered when switching
between the outputs of turntable pre -amps, projectors,
or other sources. This amplifier may be used in any
audio system where -34 dbm is available to its input.
DESCRIPTION
The Type BA -9 -A plug -in uni -level amplifier is
designed to replace the Type BA -12 -C plug -in program /monitor amplifier when used as a program
amplifier, and when features of automatic level -control are desired.
The Type BA -9 -A amplifier, when operated at an
output level of +20 dbm, supplies gain -control
characteristics over a range of 30 db with a rise in
output level of only 10 db. This is a 3:1 compression
ratio. At +30 dbm output, the Type BA -9 -A has a
compression ratio over a 30 db range of 5:1.
The threshold control may be set for a range varying from 0 dbm at a compression ratio of 1.6:1, to
+30 dbm at a compression ratio of 5:1. Recommended
threshold level is +20 dbm with a resultant compression ratio of 3:1.
A switch is incorporated on the front of the amplifier
which permits changes in attack and recovery time.
In the DOWN position of the switch, the amplifier
has a dual recovery time wherein the recovery time is
an automatic function of the nature of the program
material. For short, single peaks, approximately 0.9
seconds is required for 63 percent recovery of gain
after the signal has dropped below the gain- reducing
level. For sustained or rapidly recurring peaks, approximately 0.9 seconds is required for 40 percent of
gain recovery, increasing automatically up to about
34 seconds for 90 percent of gain recovery. The typical
attack time is approximately 11 milliseconds.
In the UP position of the switch, the amplifier is an
average level - control device which will work on average levels of program material changes. In essence,
single short peaks will not cause gain reduction, but
sustained increases in over -all program level or rapidly
reoccurring short peaks will cause automatic -gain
reduction depending upon the over -all amplitude of
the incoming signals. The typical attack time is approximately 62 milliseconds. The average recovery
time is 13 seconds for 90 percent recovery.
These effects are accomplished by the use of a bias
generator which in turn is composed of a full -wave
rectifier circuit charging simple RC networks. The out-
put of the bias generator supplies a variable d -c bias to
the control grids of a General Electric Type GL -6386
tube (a dual remote cutoff triode).
Gain reduction may be read on any standard VU
meter. A third scale, in the form of a decal supplied
with the amplifier, may be applied to the VU meter's
face. By the use of a suitable switch connected between the VU meter multiplier and meter movement,
gain reduction will be indicated over a 30 db range.
MECHANICAL SPECIFICATIONS
UNITS
One Type BA -9 -A plug -in uni -level amplifier
DIMENSIONS
Depth: 105.1 inches
Height: 5 31 inches
Width: 31 , inches
WEIGHT
6
lbs
MOUNTING
Four amplifiers may be mounted in one Type FA -23 -B shelf
which in turn mounts flush in the front of a standard EIA cabinet rack. Mounting height of the Type FA -23 -B shelf (accessory) is seven inches (four rack units).
OPERATING CONDITIONS
Maximum ambient temperature: 113 F (45 C
Maximum relative humidity: 95 percent
ELECTRICAL CONNECTIONS
POWER AND SIGNAI.
Through Cinch -Jones 2400 series plug, plugging into female
mate on Type FA -23 -B shelf. Connections on plugs are
solder terminal.
THRESHOLD BIAS
VOLTAGE
Tip jacks
SAFETY PROVISIONS
No voltage applied to unit until plugged into mating source.
No exposed voltages.
COMPRESSION
CHARAC TERISTIC
TYPE
EIA
9 -S
UNI LEVEL
AMPLIFIER
30
-
:5
_ 20
THRESHOLD
I
IO
:D
ID
IMPUT
AROVE
THRESHOLD
:S
IM
D
SO
D
.1
bm OUTPUT
THRESHOLD
i0seln
THRESHOLD
:0a Am OUTPUT
THRESHOLD.
SOSAI.b
OUTPUT
OUTPUT
Amplifiers
AUDIO
Plug -in Uni -level Amplifier
Page A9
Type BA -9 -A
OUTPUTS
ELECTRICAL SPECIFICATIONS
SIGNAL
CIRCUIT OPERATION
150 '600 ohms impedance, shipped wired for 600 ohms.
Balanced output.
Threshold control (a 0 dbm:
0 dbm to +18 dbm output
Threshold control
20 dbm:
+20 dbm to +30 dbm output
Threshold control Of 30 dbm:
+30 dbm to +36 dbm output
(All signals below and up to threshold level, linearly
amplified.)
Consists of a General Electric Type GL -6386 push
pull triode variable gain input stage supplying signal
to a push -pull output stage utilizing two Type
6V6GT power tubes. The signal for the bias generator
rectifier is supplied from the plates of the output
stage. The bias generator uses a full wave rectifier
Type 6AL5 whose output supplies a bias voltage to the
control grids of the GL -6386 tube. A switch selects
time constants so that either an average control of
program material or a peak compression of program
material is obtained.
-
Isoi600n
PP
GAIN
CONTROL
STAGE
II
oNPUT
(EE
TEST
Two tip jacks for threshold bias setting.
(as Compressor meter)
Pins eight and nine on Cinch-Jones 2400 series plug.
EXTERNAL VU METER
PP
OUTPUT
STAGE
IIOUTPUT
EXTERNAL POWER SUPPLY
Type BP -10 -B (Accessory).
CONTROLS
Threshold setting control.
Average program dual recovery switch.
GENENAi(W
TUBE COMPLEMENT
I
Simplified block diagram, plug -in uni -level amplifier, Type BA -9 -A
I
2
PERFORMANCE
GL -6386
6AL5
-6V6GT
FREQUENCY RESPONSE
+ or -1 db, 50- 15,000 cycles under any condition of gain
reduction up to 30 db
GAIN
54 db
HARMONIC DISTORTION
(Threshold control set for +20 dbm output.) At any level up
to 30 db of gain reduction, the total harmonic distortion between 100 and 15,000 cycles is 1 12 percent or less; from 50 to
100 cycles the distortion rating is 2 percent or less.
OUTPUT NOISE
Less than
-55 dbm
11
TIP JACKS
POR
TN REMOLD
ATTACK TIME
Dual
COKTROL
Average
milliseconds
sETUr
62 milliseconds
AVERAGE
PROGRAM
RECOVERY TIME
/OUAL¡
(Dual)
Single short peaks 0.9 seconds for 63 percent recovery
Sustained peaks 0.9 seconds for 40 percent recovery
34 seconds for 90 percent recovery
(Average)
13
seconds for 90 percent recovery
INPUTS
POWER
Plate --300 volts d -c (E 77 milliamperes
Heater -6.3 volts a -c (u 1.55 amperes
Threshold control (ìt.0 dbm output:
54 dbm to
24 dbm input
Threshold control C 20 dbm output:
34 dbm to -4 dbm input
Threshold control (a 30 dbm output:
24 dbm to +6 dbm input
-
INPUT IMPEDANCE
Unloaded transformer
SOURCE IMPEDANCE
150 600 ohms, shipped wired for 600 ohms. Balanced
input.
l.._..-
Tip jacks and switch, plug -in uni -level
amplifier, Type BA -9 -A
HOW TO ORDER
When ordering please specify:
Type BA -9 -A plug -in uni -level amplifier. The type
number includes the amplifier, one set of operating
tubes, one gain reduction scale (decal) for applying to
a standard 4 -inch VU meter, and installation and
operating instructions.
SIGNALS
-
RECOVERY
SWITCH
ACCESSORIES
Type FA -23 -B shelf-for rack mounting four
1
Type BA -9 -A amplifiers
-Type BP -10 -B power supply
1 -Type FA -46 -A2 shelf for mounting four Type
BA -9 -A amplifiers in base cabinet
1 -7774619P1 VU meter (for steel panels)
1- 7774619P2 VU meter (for aluminum or nonmagnetic panels)
1
Amplifiers
Plug -in Uni -level Amplifier
Page A10
Type BA -9 -A
TYPICAL APPLICATIONS
MASTER
MIER
Fig. 1.
The
BA -9 -A
PROGRAM AMP POSITION
GAIN CONTROL
BUS
amplifier as an automatic level control amplifier
uni -level
The application of automatic level control to a
studio system is outlined in Fig. 1.
The uni -level amplifier can be used to control level
differences between two or more program sources, as a
program line compressor, automatic master gain control, expander- compressor operation, or as a straight
program amplifier.
MASTER
GAIN CO TROL
PRE -AMP
BA -I
REMOTE LINE
-H.
REMOTE LINE
INPUT TO CONSOLE
REMOTE LINE
Fig. 3.
PROGRAM AMP POSITION
Unattended remote operation
When it is desirable to operate the uni -level ampliunattended remote operations, either of the
above single -line diagrams can be used. A typical
setup would be to set levels so that what is considered
a normal signal level causes about 15 db gain reduction. For a signal increase of 15 db line variations
will be only 5 db.
fier on
MICROPHONE
t
TURNTABLE
Fig. 2.
make an announcement, it is only necessary to talk
into the microphone. The turntable will fade into the
background and will be separated from the microphone announcement by 20 db.
The resultant increase in output signal level will be
less than seven db, which can be easily handled by the
transmitter limiting amplifier. Depending upon which
position the AVER /DUAL switch is in will determine
the speed with which the turntable level will return to
normal.
uni-level amplifier as an automatic
fader control
Using the BA -9 -A
The use of the "uni- level" amplifier as an automatic
fader control is outlined in Fig. 2. In this application,
the turntable signal level should be set so that it
results in a GR scale reading of about two to three db
of gain reduction. The microphone level at the mixer
bus is set about 20 db higher than the turntable signal
at the same point.
The microphone and turntable inputs can now be
used together with no manual fading required. Whenever it is desired to use the microphone channel to
THRESHOLD
AUDIO
LINE
MICROWAVE
TRANS
Fig. 4.
Microwave relay application of the uni -level
The uni -level amplifier can be used to prevent excessive audio variations in an audio line feeding the audio
input of a microwave system. Such an application is
shown in Fig. 4.
CONTROL (CONTROLS
AMPLIFIER OUTPUT RANGE FROM
+10 TO +30 dbm OUT )
NOS. 8 8 9 PINS
EXTERNAL VU
METER FOR
TO
DIRECT
COMPRESSION
READINGS
Plug -pins and control, plug -in uni -level amplifier, Type BA -9 -A
Amplifiers
AUDIO
Uni -level Amplifier
Page
All
Type BA -9-B
Uni -level amplifier, Type BA -9 -B
FEATURES
A -c powered
Requires only HO-125-volt a -c power for operation
Conserves rack space
Will mount in any standard rack, utilizing only 31/2 -inch
(2 RU) of vertical height
Versatile
Permits unattended remote audio operation
This amplifier used on an incoming remote line
automatically controls level variations from an unattended remote amplifier. (See Fig. 3 Typical
Applications).
Controls level differences between two or more program
sources
Level differences automatically controlled between:
(a) Turntables and /or projector outputs
(h) Network incoming signal (when properly
padded) and projectors, turntables, or announce mike pre -amps
May be used as a program line compressor
May be used as an automatic master gain control for
program line
Typical Applications)
(See Fig.
May be used as a microwave input audio control
(See Fig. 4 Typical Applications)
May be used as an expander -compressor amplifier
With average program material set for 15 db of gain
reduction, output will be compressed for incoming
signals exceeding 15 db and expanded for signals
1
below 15 db.
May be used as an automatic fader control
(See Fig. 2 Typical Applications)
May be used as a straight program amplifier with or
without level control
Removal of one tube disables automatic level control and permits use as a normal program amplifier.
Functionally interchangeable with G -E Type BA12-C plug -in program /monitor amplifier when used
for program purposes
Used as a peak level control
Amplifier will operate over a 30 db range with only a
10 db change in output
Used as an average level control device
Amplifier will operate over a 30 db range of input
level with only a 10 db change in output level
Variable threshold level
Amplifier will operate with the threshold level set at
any output between
+10 dbm and +30 dbm
Average program dual recovery
Connection permits use of amplifier as an average level
control or as a peak level control
Dual time constant eliminates program
Recovery time
is
"pumping"
an automatic function of program
material
Easily serviced
All components exposed for easy service when hinged front panel is opened
WHERE TO USE
The General Electric Type BA -9 -B uni -level amplifier is a rack -mounted, a -c powered version of the
familiar and popular Type BA -9 -A plug -in uni -level
amplifier. It is intended for automatic level control
applications in radio and TV stations, sound record-
ing studios, and industrial and public address systems.
Radio and TV Stations
In radio and TV stations the amplifier may be used
to control level differences between two or more
medium level program sources, as a program -line
compressor, as an automatic master gain control for
program or remote line, for expander-compressor
www.americanradiohistory.com
Amplifiers
Page
Al2
Uni -level Amplifier
Type BA -9 -B
operation (including automatic fading of music for
voice- over -music announcements) or as a straight program amplifier.
Sound Recording Studios
In sound recording studios the amplifier may be
used to control level differences between various voice
or music signals, or as a compressor to be used prior to
the recording amplifier.
Industrial or Public Address Systems
In industrial or public address systems, the uni -level
amplifier may be used to eliminate "blasting" due to
varying intensities of sound sources with consequent
overloading of line or power amplifiers, as a compressor- expander to control and amplify weak or
compress excessively strong input signals, or as a
micro -wave audio input control.
Due to the unique design of the Type BA -9 -B, this
amplifier may be used as either an average level -control device or as a peak level - control amplifier.
Maximums of up to 30 db in program variations
may be successfully controlled by this amplifier. It
may be used in any audio system where 34 dbm is
available to its input.
(See Typical Applications for detailed suggested
use.)
-
DESCRIPTION
Essentially, the Type BA -9 -B uni -level amplifier is
the a -c powered, rack -mounted version of its plug -in
counterpart, the Type BA -9 -A uni -level amplifier.
Other than its mounting and power supply, it is identical in performance and specification with the Type
BA -9 -A uni -level amplifier.
The Type BA -9 -B uni -level amplifier is an automatic level -control device designed to functionally
replace or supplement the Type BA -12 -C program /monitor amplifier, when used as a program
amplifier, or when features of automatic level- control
are desired.
The Type BA -9 -B amplifier, when operated at an
output level of +20 dbm, supplies gain- control characteristics over a range of 30 db with a rise in output
level of only 10 db. This is a 3:1 compression ratio. At
+30 dbm output, the Type BA -9 -B has a compression
ratio over a 30 db range of 5:1.
The threshold control may be set for a range varying
from 0 dbm at a compression ratio of 1.6:1, to +30
dbm at a compression ratio of 5:1. Recommended
threshold level is +20 dbm with a resultant compression ratio of 3:1.
A connection may be made in the amplifier which
permits changes in attack and recovery time.
The unit as shipped is connected for dual recovery
time- wherein the recovery time is an automatic function of the nature of the program material. For short,
single peaks, approximately 0.9 second is required for
63 percent recovery of gain after the signal has
dropped below the gain- reducing level. For sustained
or rapidly recurring peaks, approximately 0.9 second is
required for 40 percent of gain recovery, increasing
automatically up to about 34 seconds for 90 percent of
gain recovery. The typical attack time is approximately 11 milliseconds.
By strapping an adjacent terminal connection, the
amplifier may be changed to an average level -control
device which will work on average levels of program
material changes. In essence, single short peaks will
not cause gain reduction; but sustained increases in
over -all program level or rapidly recurring short peaks
will cause automatic -gain reduction depending upon
the over -all amplitude of the incoming signals. The
typical attack time is approximately 62 milliseconds.
The average recovery time is 13 seconds for 90 percent
recovery.
These effects are accomplished by the use of a bias
generator which in turn is composed of a full -wave
rectifier circuit charging simple RC networks. The output of the bias generator supplies a variable d -c bias to
the control grids of a General Electric Type GL -6386
tube (a dual remote cutoff triode).
Gain reduction may be read on any standard VU
meter. A third scale, in the form of a decal supplied
with the amplifier, may be applied to the VU meter's
face. By the use of a suitable switch connected between the VU meter multiplier and meter movement,
gain reduction will be indicated over a 30 db range.
Space is provided behind the hinged -front panel for
mounting an input and an output attenuator. These
attenuators may be mounted on the hinged panel by
the broadcaster to handle input or output levels of
higher or lower values than those specified for unilevel operation.
A pilot light and an OFF -ON switch is located on
the front panel for convenience. Total dimensions of
the chassis (over -all) are height 3 , inches, width 19
inches, and depth 71.) inches. Weight is approximately
f
12 1hs.
Uni -level amplifier (front view, panel open), Type BA -9 -B
Amplifiers
AUDIO
Uni -level Amplifier
Page A13
Type BA -9 -B
MECHANICAL SPECIFICATIONS
GAIN
54 db.
UNITS
One Type BA -9 -B uni -level amplifier
One miniature motor base plug for a -c power
DIMENSIONS (Over -all)
Depth:
Height:
71
inches
31.) inches (2
R.U.)
Width:
Weight:
HARMONIC DISTORTION
Threshold control set for +20 dbm output.) At any level up
to 30 db of gain reduction, the total harmonic distortion between 100 and 15,000 cycles is 1 s percent or less; from 50 to
100 cycles the distortion rating is 2 percent or less.
inches
19
12
1
lbs
OUTPUT NOISE
Less than
MOUNTING
Standard RETMA
19 -inch.
Cabinet -rack mounting.
OPERATING CONDITIONS
-50
- 55 dbm.
dbm.
(With 6V6GT)
(With 5881)
ATTACK TIME
Maximum ambient temperature 113 F (45 C
Maximum relative humidity 95 percent
Average
62 milliseconds
Dual
11
ELECTRICAL CONNECTIONS
RECOVERY TIME
A -c power- Recessed miniature motor base receptacle and plug
Signal - Solder lug terminal strips
Gain Reduction Solder lug terminal strips
Average Program Dual Recovery -Strap on adjacent terminal
SAFETY PROVISIONS
No exposed voltages when hinged -front panel is closed. A -c
switch provided on panel for independent operation of unit.
Pilot, light on front panel indicated amplifier operation. A -c
milliseconds
(Dual)
Single short peaks 0.9 second for 63 percent of recovery
Sustained peaks 0.9 second for 40 percent recovery
34 seconds for 90 percent recovery. (Average)
13 seconds for 90 percent recovery
INPUTS
117 -volt a -c 50/60- cycle, 65 -watt (Note: B+ voltadjustable to 300 -volt d -c for a -c inputs varying
between 110 -125 volts.)
Power
age is
power- fused.
SIGNALS
Threshold control
input.
Threshold control
input.
Threshold control
input.
ELECTRICAL SPECIFICATIONS
CIRCUIT OPERATION
Consists of a General Electric Type GL -6386 push pull triode variable gain input stage supplying signal
to a push -pull output stage utilizing two Type 6V6GT
power tubes. The signal for the bias generator rectifier
is supplied from the plates of the output stage. The
bias generator uses a full -wave rectifier Type 6AL5
whose output supplies a bias voltage to the control
grids of the Type GL -6386 tube. A strap to an adjacent
terminal will select the correct time constants to obtain
the average control of program material. As shipped,
the amplifier is connected for peak compression of
program material.
Input impedance
dbm output:
(r+
0
(a
20
(a
30 dbm
-
dbm output:
-54 dbm
-34
to
-24
dbm
4
dbm
dbm to
output: -24 dbm to +6 dbm
Unloaded transformer.
Source impedance -150 600 ohms, shipped wired for 600
ohms. Balanced input.
OUTPUTS
150 600 ohms impedance, shipped wired for 600
ohms. Balanced output.
Signal
COa1PI1ESS10N
CHARACTERISTIC
T.PE
URI-LEVEL
AMPLIFIER
M.9-
]0
20
teD/GOOA
II
INPUT
PP
GAIN
CONTROL.
STAGE
PP
OUTPUT
STAGE
I50/60011
OUTPUT
THRESHOLD
O
Pam OUTPUT
1045n. OUTPUT
TMRESMOLD
BIAS
GENERATOR
10
TMRESMOLO
Simplified block diagram, Type BA -9 -B uni -level amplifier
THRESHOLD
4
2045.
OUTPUT
SOATR OUTPUT
PERFORMANCE
FREQUENCY RESPONSE
r or -1 db, 50- 15,000 cycles under any condition of gain
reduction up to 30 db
Uni -level amplifier (rear view) Type BA -9 -B
www.americanradiohistory.com
20
10
INPUT
60vE
T..RESMOLO IN
25
50
DS
f/'
-
Amplifiers
Uni -level Amplifier
Page Al 4
Type BA -9 -B
Threshold control Or 0 dbm: 0 dbm to +18 dbm output
Threshold control (a, 20 dbm: +20 dbm to +30 dbm output
Threshold control (a 30 dbm: +30 dbm to +36 dbm output
(All signals below and up to threshold level, linearly amplified)
EXTERNAL VU METER
Solder lugs on terminal strip
CONTROLS
Threshold setting
TUBE COMPLEMENT
1 1
- -GL -6386
2
6AL5
-6V6GT
1- -5Y3GT
HOW TO ORDER
When ordering, please specify:
General Electric Type BA -9 -B uni -level
amplifier (for rack mounting). (The Type Number includes the amplifier, one set of operating tubes, one
gain reduction scale (decal) for applying to standard
4 -inch VU meter, one miniature motor base plug, and
installation ánd operating instructions.)
ACCESSORIES
The use of the "uni- level" amplifier as an automatic
fader control is outlined in Fig. 2. In this application,
the turntable signal level should be set so that it
results in a GR scale reading of about two or three db of
gain reduction. The microphone level at the mixer bus
is set about 20 db higher than the turntable signal at
the same point.
The microphone and turntable inputs can now be
used together with no manual fading required. Whenever it is desired to use the microphone channel to
make an announcement, it is only necessary to talk
into the microphone. The turntable will fade into the
background and will be separated from the microphone announcement by 20 db.
The resultant increase in output signal level will be
less than seven db, which can be easily handled by the
transmitter limiting amplifier. The speed with which
the turntable will return to normal is determined by
the operation of the uni -level recovery circuits. It may
be used either in the dual or average conditions for
attack and recovery. The speed with which the turntable level will return to normal is determined by the
average or peak condition of attack and recovery of
the amplifier.
1- 7774619P1 VU meter (for steel panels)
1- 7774619P2 VU meter (for aluminum or nonmagnetic panels)
REMOTE
LINE
TYPICAL APPLICATIONS
MASTER
ML
ER
BUS
GAIN CONTROL
PROGRAM
AMP POSITION
REMOTE LINE
INPUT TO CONSOLE
REMOTE LINE
Fig. 3.
Fig. 1.
The
BA-9-6 uni-level amplifier as an automatic level- control
amplifier
The application of automatic -level control to a
studio system is outlined in Fig. 1.
The uni -level amplifier can be used to control level
differences between two or more program sources, as a
program line compressor, automatic master gain control, expander- compressor operation, or as a straight program amplifier.
When it is desirable to operate the uni -level amplifier on unattended remote operations, either of the
above single -line diagrams can be used. A typical
setup would be to set levels so that what is considered
a normal signal level causes about 15 db gain reduction. For a signal increase of 15 db line variations
will be only five db.
t
AUDIO
MASTER
GAIN CONTROL
PROGRAM
LINE
Fig. 4.
TURNTABIE
Using the BA -9 -B uni -level amplifier as an automatic fader
control
HA-
9-
MICROWAVE
TRANS
/
AMP POSITION
MIC RUFHORE
Fig. 2.
Unattended remote operation
Microwave relay application of the uni -level
The uni -level amplifier can be used to prevent excessive audio variations in an audio line feeding the
audio input of a microwave system. Such an application is shown in Fig. 4.
Amplifiers
AUDIO
Transistor Cue /Talkback Amplifier
Page A15
Type BA -28 -A, Plug -in
Cue /talkback
amplifier Type BA-2$.A
FEATURES
All transistors -no tubes in the circuitry
Space savings -mall, compact, light weight
Low voltage -low power drain
Plug -in construction for ease in maintenance
Fiberglas wire board
WHERE TO USE
The General Electric Type BA -28 -A transistor cue
talkback amplifier provides the gain necessary to
raise an audio signal from mixer -bus level to a level
( +27 dbm) sufficient for cuing and studio talkback
service.
This amplifier is designed for use in the Type BC21 -A audio console for any custom console employing
transistor amplifiers.
DESCRIPTION
The General Electric Type BA 28 -A transistor cue
talkback amplifier is a compact plug -in audio unit
constructed on a printed -wire board and mounted on
an "L" shaped aluminum frame.
This amplifier contains eight separate transistor
stages. The first two stages are coupled directly in a
Darlington compound connection. The second stage is
capacitively coupled to the third stage which is
directly coupled to the fourth stage. The fourth stage
is a common emitter directly coupled to an emitter
follower which is then directly coupled to another
common emitter. The latter stage is directly coupled
to a common collector Darlington compound connected output stage. This amplifier differs from the
Type BA -22 -A transistor program amplifier only in
the quality of the output. In this unit, an open core
and coil -type output transformer produces a lower
quality output.
Amplifiers
Page A16
Transistor Cue /Talkback Amplifier
Type BA -28 -A, Plug -in
MECHANICAL SPECIFICATIONS
Type number includes amplifier assembly, a set of
transistors and a set of installation and operating
instructions.
ELECTRICAL SPECIFICATIONS
DIMENSIONS
POWER REQUIREMENTS
Height
Length
, inches
Width
44
955inches
Weight
21
41
inches
_ lbs
PERFORMANCE
d 2 db 100 10,000 cps
Gain: 75 db matching input
Distortion: 3 percent or less at f-24 db (or rated output level)
Noise: S N ratio of 60 db
Frequency Response:
ill
Colts d
t )ti) ma
c
SIGNAL INPUT
Transformer matching
MOUNTING
Unit plugs into Type BC -21 -A audio console or, by utilizing a
Type FA -48 -A equipment shelf, up to four of these units can be
rack mounted in any standard EIA rack such as the Type
PR -I -A equipment rack.
OPERATING CONDITIONS
SIGNAL OUTPUT
but) ohms balanced
balanced at 27 dbm
f
dbm
or unbalanced -connected for 600 ohms
output level
3
2N324 General Electric
2N320 General Electric
2N553 Delco
COMPLIANCE
Complies with all applicable FCC and EIA specifications.
ELECTRICAL CONNECTIONS
All connections are made by a 9 -pin plug which
printed -wire board.
is
attached to
SAFETY PROVISIONS
No power is applied to the unit unless it is plugged into its
mating socket. When the unit is plugged in and console closed
there is no exposed voltage. The maximum voltage applied to
the unit is 50 volts d -c.
HOW TO ORDER
When ordering please specify: Type BA -28 -A cue
talkback amplifier (requires external power supply).
ACCESSORIES
Type FA 48 A equipment shelf.
Type BP -21 A 50 25 -volt transistor power supply
(regulated).
.;Utinu
Up NOT
GHOUNI)
TIMNSISTpI:
r) CHASSIS
Cue /talkback
- 22
TRANSISTOR COMPLEMENT
I
Max ambient temperature, 131 F (55 C
Max relative humidity, 95 percent
maximum input level
amplifier Type BA -28 -A installed in equipment shelf Type FA -48 -A
Amplifiers
AUDIO
Audiomatic Limiting Amplifier
Page A17
Type BA -7 -A
Audiomatic limiting amplifier, Type BA -7 -A
FEATURES
"Thumping" virtually eliminated
New design uses a new method for eliminating the
"thump" component common to limiter actions
Greater limiting range
The new audiomatic limiter incorporates a limiting range
of 20 db, an increase of 8 db in limiting range over the
popular General Electric Type BA -5 -A limiter
Higher output level
The new audiomatic limiter has an output level of +27
dbm, an increase of 15 dbm in output level as compared to the General Electric Type BA -5 -A limiter
New program -controlled recovery circuit utilized
This circuit permits large amounts of gain reduction with
a negligible pumping effect
Two different types of recovery circuits offered
The conventional dual RC type may be used, or the new
program -controlled recovery circuit may be used
Attack time effectively zero
Seventy microsecond attack time is obtained by means
of a high -speed bias generator
Extremely low transient waveform distortion
Very high compression above threshold of gain
reduction action
"Motor- boating" can not occur
Automatic control voltage is not a function of the output
voltage of the controlled amplifier eliminating "motor boating"
Very low steady -state distortion and noise level due
to inverse feedback circuits
Instant accessibility
Vertical rack- mounting chassis utilizes single- hinged
front -cover panel
Compact
Entire unit measures only 101/2 inches high by 9 inches
deep by 19 inches wide
Single unit
All amplifiers and power supply are mounted on one
small chassis
One VU meter supplies all required readings
Single VU meter is used to read input level to control
amplifiers, gain reduction, output level of limiter, and
for balancing of modulator
No matched tubes required
The Type BA -7 -A audiomatic limiting amplifier uses only
18 tubes -none of which require matching
Plug -in connections
All external connections are made on plugs. It is not
necessary to solder or unsolder connections when installing or removing amplifier
Thoroughly shielded
All transformers, oscillator, and RF power amplifier
sections, plus tubes in RF section, are thoroughly shielded
to prevent radiation and interaction
Excellent frequency response with low distortion up
to practical limit of gain reduction. (See Electrical
Specifications)
www.americanradiohistory.com
Amplifiers
Page
Audiomatic Limiting Amplifier
Al 8
Type BA -7 -A
WHERE TO USE
Mechanical Components
The General Electric Type BA -7 -A audiomatic
limiting amplifier is a peak- limiting device designed to
permit a substantial increase in the average program
level without danger of any audio peaks exceeding a
predetermined level.
The output of the Type BA -7 -A audiomatic limiting
amplifier is sufficient to drive any EIA, AM, FM, or
TV audio transmitter to 100 percent modulation. It is
readily adaptable for use in recording systems in the
tape, disc, and motion picture sound recording industries. As such, it may be used either before or after pre emphasis.
Mechanically, the audiomatic limiting amplifier is
complete with power supply on one chassis. As such it
requires only 10 , inches of vertical rack space, and
9 inches of rack depth. This vertical rack - mounted
unit is equipped with a hinged -front panel allowing
instant accessibility to the internal controls and corn ponents. Only 110 watts of 110 -125 volts a -c power
are required for its operation. All connections are made
Input Level
Control
VU Meter
Attenuator
Output Level
Control
Front panel of amplifier BA -7 -A
DESCRIPTION
The General Electric Type BA -7 -A audiomatic
limiting amplifier is designed as a fast -acting, thump less, peak -limiting audio amplifier. It incorporates two
new outstanding features, the first being a new and
effective method of eliminating the "thump" component common to all limiter actions. The second outstanding feature is the incorporation of the new program- controlled recovery circuit which permits the
use of larger amounts of gain reduction with negligible
pumping effect. These features are made possible by
the use of a new method of limiting, namely the audio
modulation of an RF carrier, the imposition of limiting
action on this signal, and the demodulation of the RF
to render a virtually thumpfree, peak -limited audio
signal.
The use of this new design permits an 8 db increase
in limiting range, a 15 db increase in output level, and
a reduction in physical size as compared to the
popular General Electric Type BA -5 -A limiting amplifier. Attack time is effectively zero - being limited to
approximately 70 microseconds by means of a highspeed generator. A switch is provided which will allow
the amplifier to operate either on the new program controlled recovery circuit where large amounts of
gain reduction are expected, or on the conventional
dual RC recovery circuit. Should conditions require it,
this amplifier may be used in a backward acting mode
of operation.
I
Adjustments for
Proper Compression
Characteristics
Controls
for Adjusting
Balance of Modulator
Selects Dual R.C.
or Program Control
Recovery Circuit
Meter Zero
for Gain
Reduction Position
Set
Front view of amplifier BA -7 -A with front panel open to show
interior controls
by means of a single 10 -pin Cinch -Jones plug and a
standard a -c plug and receptacles, located on the rear
of the amplifier chassis. A VU meter is used to measure
signal levels and gain reduction.
Electrical Components
Electrically, the audiomatic limiting amplifier consists of an amplifier and power supply mounted on one
chassis. The amplifier incorporates five sections: a preamplifier, an oscillator and RF section, a bias generator, a control section and an output stage.
The operation of the limiting amplifier on the audio
signal is as follows: The incoming audio signal is fed
into the loaded input of the preamp stage. From here
the signal is split in two paths, the first going to the
balanced modulator in the control section, and the
second to the bias generator. In addition to the audio
signal, the balanced modulator receives a constant
amplitude 10- megacycle carrier from the oscillator and
RF amplifier section. This carrier is then amplitude modulated by the audio signal, the main carrier is
suppressed, and the resulting output signal, consisting
of modulated sidebands only, is fed to the variable
gain RF stage in the control section. Simultaneously
the audio fed to the bias generator section is first
passed through a voltage correction network, through
a slope control, then to a voltage amplifier, a phase
Amplifiers
AUDIO
Audiomatic Limiting Amplifier
Page 419
Type BA -7 -A
PRE-AMP UNIT
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Simplified block diagram of amplifier BA -7 -A
splitter, and then a push -pull cathode follower. The
output of the cathode follower is split in two parts,
the first being fed to the program control recovery
circuit, the second being fed to a full -wave rectifier
diode. The variable d -c voltage resulting from this
latter diode's action is then applied to the grid of the
variable gain RF stage in the control section. This
variable d -c voltage has the effect of controlling the
amplitude of the audio modulated sidebands. Since
there is no carrier present at the grid of this control
stage, the low frequency or thump component, created
by varying the control voltage, is not passed through
the RF circuit and thus is not detected later. These
controlled sidebands are then passed to a synchronous
detector which also receives a 10- megacycle constant
amplitude carrier from the oscillator and RF section.
The carrier and controlled sidebands are recombined
and the resultant audio is detected. The audio signal is
then fed to a voltage amplifier, a phase splitter, and
then the push -pull output stage of the limiting amplifier. From a tertiary winding on the output transformer, voltage is fed back around the output unit.
The secondary of the output transformer feeds the
line through an output attenuator which is bridged by
a VU multiplier attenuator. The VU meter is switched
to read the output level, the amount of gain reduction,
the input level to the balanced modulator, and can be
used to check modulator balance.
Recovery of the amplifier is controlled by two different types of circuits, both located in the bias generator section. The first circuit is the conventional dual
RC circuit. The second circuit is the new program controlled recovery circuit. This latter recovery control is obtained by placing a diode in the discharge
path of a capacitor in the recovery circuit. The diode
is biased to an equivalent voltage of 15 db of gain
reduction. The amplitude of the audio trigger voltage
from the cathode -follower (bias generator) output is
adjusted to produce an artificial verge of 3 db. Thus,
below 3 db of gain reduction the diode will not conduct, resulting in a very slow discharge rate and
consequent slow recovery time of the amplifier. Between 3 db and 20 db of gain reduction the audio
trigger voltage will cause the diode to conduct. This
results in a voltage discharge of the capacitor which
produces a normal amplifier- recovery rate. However,
during the absence of program material the diode will
cease to conduct and recovery of the amplifier will
be appreciably slowed down. Hence, the audio -gain
recovery is controlled by the variances in peak audio
amplitudes, with the resulting advantage that large
amounts of gain reduction may be used with negligible
pumping effect. Where only small amounts of gain
reduction from threshold to 6 db are required, the dual
RC circuit should be used.
The recommended compression ratio for this amplifier operation is 20:1 when used in either the dual RC
or program controlled recovery operational mode. If
used as a backward acting amplifier, the recommended compression ratio is 2:1.
Balanced tubes are not required in this unit. Only a
simple adjustment of the modulator balance controls
is necessary to balance the modulator. A push- button
balance check switch provides an easy, rapid, and
convenient means of checking the modulator balance.
Performance, distortion ratings, and other useful
information may be found in the ELECTRICAL
SPECIFICATIONS section.
-
Amplifiers
Audiomatic Limiting Amplifier
Page A20
Type BA -7 -A
MECHANICAL SPECIFICATIONS
UNITS
1- BA-7 -A
audiomatic limiting amplifier
DIMENSIONS
Depth
Height
9
Width
inches
10? 1 inches
(6 rack units)
Weight
19 inches
42 lbs
MOUNTING
Standard EIA
19 -inch
rack -mounting with hinged front panel
OPERATING CONDITIONS
Maximum ambient temperature: 113 F (45 C)
Maximum relative humidity: 95 percent
ELECTRICAL CONNECTIONS
Input and output audio signals made through a 10 -pin Cinch Jones plug and receptacle. A -c power made through standard a -c
plug and receptacle
the variable gain RF stage (68Á6) to control the
amplitude of the sidebands. The controlled sidebands
are passed to a synchronous demodulator using a
6AL5. The demodulator receives a 10 M C constant
amplitude carrier from the same source as the balanced modulator for the detection process. The audio
signal is then fed into a 12AX7 voltage amplifier and
phase splitter which drives the push -pull 6463 amplifier output stage. Two different types of recovery
circuits can be used, the conventional dual RC type or
the new program recovery circuit.
Performance
OUTPUT LEVEL
Variation of *0.5 db from verge to
from 18 to 20 db of limiting
-1.5 db
17
db of limiting +0.5
FREQUENCY RESPONSE
SAFETY PROVISIONS
Power supply primary fused. All exposed wiring normally
covered by hinged front panel
VENTILATION
Normal rack ventilation. No blowers required
1
db from 50 to 15,000 cycles (from verge to 20 db of limiting)
DISTORTION
From verge to 12 db of gain reduction:
1 percent or less, 50 to 15,000 cycles
From 12 db to 20 db of gain reduction:
1.5 percent or less, 100 to 15,000 cycles
2.5 percent or less, 50 to 100 cycles
ATTACK TIME
Approximately 70 microseconds
COMPRESSION RATIO
Forward acting:
Backward acting:
20:1
2:1
RECOVERY TIME
Dual RC
Approximately 0.5 seconds for short peaks for 63 percent gain
recovery. For sustained or rapidly recurring peaks, the recovery
time is approximately the same for 50 percent recovery and
increases to 10 seconds for 90 percent gain recovery
Rear
view of BA -7 -A amplifier
ELECTRICAL SPECIFICATIONS
Type of Circuit
(See block diagram of circuitry.) Audio signal is fed
into preamplifier through an input transformer with
terminated secondary into a 5879 voltage amplifier
and 12BH7 cathode - follower output. The preamplifier
incorporates inverse voltage feedback. The audio signal is then split into two paths, one into the balanced
modulator using a 6AL5, the other into the bias generator circuit. A ten M C constant amplitude carrier is
generated by an oscillator consisting of one -half of a
12AT7 and amplified by a 6AU6 power amplifier.
This carrier signal is fed to the balanced modulator
and is modulated by the audio signal. The output of
the modulator consists of sidebands only with the
carrier suppressed. The sidebands are then fed to a
variable gain RF stage using a 6BA6. The audio signal
which is fed to the bias generator is passed through a
voltage correction network it is then fed into a 12AX7
voltage amplifier and phase splitter, which drives a
12AT7 push -pull cathode -follower. Full -wave rectification is then achieved by using a 6AL5 dual diode.
This variable d -c voltage is then applied to the grid of
Program -controlled Recovery
Determined by type of program material
SIGNAL TO
Noise Ratio
65 dbm
t 27
below
threshold or below
-45 db or better
Thump Ratio
TOTAL GAIN
Amplifier set at verge of limiting 57 dbm,
dbm output at
t2 db
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AUDIO
Amplifiers
Audiomatic Limiting Amplifier
Page A21
Type BA -7 -A
INPUTS
Power
110
Internal Chassis
watts, 110
Audio
117 125 volts a -c, 50,611 cycles, single ',has(
600,'150 ohms, balanced or unbalanced. Center tap or either
side may be grounded as desired
Minimum input level at verge: -30 dbm
Maximum input level at verge: 0 dbm
Input level adjustable by 30 step, 1 db per step control
program controlled recovery)
TUBE COMPLEMENT
OUTPUTS
600 -ohm unbalanced "T" (can be used to feed a balanced
line). One side may be grounded if desired
1
-
1
4
1
OUTPUT LEVELS
+27 dbm. Output variable down to
attenuator, 30 steps, 0.5 db per step
Slope control (for adjusting gain reduction characteristics)
Delay bias control (for adjusting gain reduction characterist ics
Zero meter adjust control (zero setting of meter for gain
reduction use
Push- button balance check switch
Recovery selector switch (switches between dual RC and
12
dbm by use of "T"
2
5879
-12BH7
6AL5
6BA6
12AT7
2 2
1
1
1
6AU6
12AX7
-6463
5U4GA
OB2
HOW TO ORDER
CONTROLS
Front Panel
Input level control (potentiometer)
VU multiplier ( "T" attenuator)
VU meter switch (selects pre-amp output, gain reduction or
amplifier)
Output level control ( "T" attenuator, 0.5 db per step, 30
steps)
Power switch
When Ordering Please Specify:
General Electric Type BA -7 -A audiomatic
limiting amplifier. (The type number includes the
amplifier, one set of operating tubes, one 10 -pin CinchJones plug, one a -c plug, and installation and operating instructions.)
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Amplifiers
AUDIO
Transistor Monitor Amplifier
Page A23
Type BA -24 -A, Plug -in
Type BA -24 -A monitor amplifier
MECHANICAL SPECIFICATIONS
FEATURES
All plug -in transistors -no tubes in the circuitry
Plug -in amplifier construction for ease in maintenance
Space saving -small, compact,
DIMENSIONS
Height
Length
95
inches
ii inches
Width
4% inches
Weight 2!:¡ lbs
lightweight
Low voltage -low power drain
Fiberglas wire board
MOUNTING
This amplifier plugs into the Type BC -21 -A audio console or,
by utilizing a Type FA -48 -A shelf, up to four of these units may
be rack mounted in any standard EIA rack such as the Type
PR -1 -A equipment rack.
WHERE TO USE
The General Electric Type BA -24 -A transistor
monitor amplifier is capable of bridging a number of
different circuits and providing the gain necessary to
raise an audio signal to loudspeaker level for aural
evaluation of the program line, incoming remote lines
and other sources.
OPERATING CONDITIONS
Max cabinet ambient temperature, 131 F (55 C)
Max relative humidity, 95 percent
ELECTRICAL CONNECTIONS
DESCRIPTION
The Type BA -24 -A transistor monitor amplifier is a
compact, plug -in audio amplifier constructed on a
printed -wire board and mounted on an "L" shaped
aluminum frame.
This broadcast amplifier consists of unloaded input
transformer which feeds a Darlington compound -connected stage. The third stage is an emitter follower
which drives the common emitter fourth stage which
in turn drives another common -emitter stage.
All electrical connections are made by a
attached to the amplifier wire board.
9 -pin plug which is
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response: 2 db, 5U 15,000 cps
Gain: 80 db matching input
Distortion: 112 percent or less at +33 dbm
Noise: S N ratio, 60 db at +33 dbm output
Amplifiers
Transistor Monitor Amplifier
Page A24
Type BA -24 -A, Plug -in
COMPLIANCE
POWER REQUIREMENTS
Complies with all applicable FCC and EIA specifications
25 volt d -c at up to 4(0) nct
SIGNAL INPUT
Matching input, maximum input level
SIGNAL OUTPUT
8 150 600 ohms
at +33 dbm
12
25 dbin
watts
CONTROLS
HOW TO ORDER
When ordering, please specify Type BA -24 -A transistor monitor amplifier (requires external power
supply). The type number covers the amplifiers, a set
of transistors, and a set of installation and operating
Not part of amplifier. Terminals provided for mounting a
750K ohm potentiometer inter-stage gain control
instructions.
TRANSISTOR COMPLEMENT
ACCESSORIES
5
1
2
1
2N324 General Electric
2N320 General Electric
CTP- 1123 -Clevite
2N169A General Electric
Type FA -48 -A equipment shelf
Type BP -20 -A 25 -volt power supply
2R74P25 750K carbon potentiometer
Type SA -24 -A monitor amplifier, with interstage gain control, installed in Type FA -48 -A equipment shelf
AUDIO
Amplifiers
Transistor Monitor Amplifier
Page A25
Type BA -34 -A
3
Transistor monitor amplifier, Type BA -34 -A
Monitor amplifier (rear view)
FEATURES
Extremely versatile
May be connected for matching or bridging input
Both line- and voice -coil outputs have transformer
isolation
Has multi- impedance inputs and outputs
Power -line voltage variations do not affect operation
High gain monitor amplifier
100 db of gain (unloaded input)
Uses
readily available, low cost, low noise transis-
tors
amplifier uses four 2N508's, two 2N1925's, one
2N214, two 2N2144's, and one 2N456A
Wide use of these transistor types in other amplifier
designs reduces the necessity of stocking many different
spares
All transistors, including the power transistors, plug into
transistor sockets
The
Magnetically and electrically shielded transformers
Interstage gain control allows up to
without external attenuation
-30
dbm input
Compact
pickup from this and adjacent equipment is
minimized by the use of extra shielding in the transformers, and the use of a steel -amplifier cover
Stability is improved by the use of negative feedHum
back
31/4-inch height and 4 -inch width permit four amplifiers
to be mounted side -by -side on one shelf in 31/2 inches of
vertical -rack space
An accidental short circuit of the output will not damage
easy removal for
Excellent frequency response with low distortion
r
db 30 to 15,000 cycles at +40 dbm output
construction permits
maintenance and service
Plug -in
1
All external connections are made through one Amphenol blue ribbon connector (audio); and one Amphenol, U L approved 3 -wire a -c plug (power)
A conventional 2 -wire a -c extension cord may also be
used for a -c power connections. Mating sockets and
mounting bracket are included with each amplifier
Contains built -in, regulated power supply
amplifier will operate with full power from 117
The
15
volts, 50 60 cycles
The
power transformer can be strapped for operation
from 230
t
15 volts, 50 60 cycles
Rated at ten watt output
the output transistors, nor even blow the fuse, due to
designed -in protection features
percent or less harmonic distortion 50 to 15,000 cycles
11/2 percent or less harmonic distortion 30 to 15,000
1
cycles
WHERE TO USE
The General Electric Type BA -34 -A monitor amplifier is a versatile audio amplifier designed to serve as a
general - purpose monitoring amplifier in radio and
television stations, in recording studios, and in motion
picture studios. It may be used as a monitor amplifier -
bridging program or other lines to furnish power for
studio speakers; a control to studio talkback amplifier,
where the talkback r,icrophone is fed into the Type
BA -34 -A without preamplification; a transcription
cueing or audition amplifier (again without preampli-
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Amplifiers
Page A26
Transistor Monitor Amplifier
Type BA -34 -A
Monitor amplifier (inside view)
fication); or as a general - purpose amplifier to feed
house monitor speakers. The unit contains its own
built -in, regulated power supply; and is intended for
shelf mounting in an audio rack, or as an attractive
desk -top unit.
COMPLIANCE
Complies with all applicable FCC and EIA specifications. The a -c connector is of the grounded type and
complies with U L standards.
DESCRIPTION
The General Electric Type BA -34 -A transistorized
plug -in monitor amplifier will deliver to the output
ten watts of power from a microphone source.
The monitor amplifier consists of an epoxy -fiberglas
printed circuit board along with input, output, and
power transformers, mounted in a "U" shaped alu-
minum frame. The front face contains a power switch,
pilot light, and volume control, whereas the rear of the
unit mounts two fuses and two connectors. All corn
ponents are located with accessibility in mind, and are
protected from dust and stray magnetic fields by
means of a steel cover.
Transistors are used throughout for low heat, low
power consumption, reliable, maintenance -free operation. Source impedances of 600 150 75 ohms feed an
unloaded transformer input for best signal to noise
ratio. The first stage is a modified Darlington compound, with interstage gain control, which feeds three
more stages of amplification.
PNP -NPN phase reversing predriver stages are
Darlington coupled to the output power transistors,
which in turn feed a push -pull output to a single
ended output transformer. Both 600 150 -ohm line and
8 -ohm voice -coil outputs are isolated from ground by
the output transformer.
Monitor amplifier (inside view)
-
AUDIO
Amplifiers
Transistor Monitor Amplifier
Page A27
Type BA -34 -A
The power supply is a low voltage, well filtered,
transistor /zener regulated design. Power line variations will not affect operation; and it may be strapped
to operate from 230 volts as well as 117 volts, 50/60
cycles.
MECHANICAL SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency response:
output
Gain: 100 db
Harmonic distortion:
1
db 30 to 15,000 cycles, +40 dbm
percent or less 50 to 15,000 cycles
1! 2 percent or less 30 to 15,000 cycles
1
NOISE
-120 dbm relative input
UNITS
POWER REQUIREMENTS
One Type BA -34 -A single plug -in assembly
25
SIGNAL INPUTS
DIMENSIONS
Height
Length
watts (at max output)
3%
inches
13% inches
Width
Weight
4 inches
9 lb
MOUNTING
Four amplifiers may be mounted in the Type FA -50 -A shelf
(accessory). Mating sockets and mounting bracket are furnished
with each amplifier, so that the amplifier may be mounted in
any other shelf of at least 3 -inch vertical space; or the amplifier may be placed in any appropriate location.
Input impedance -Unloaded transformer
Source impedance: 600/250/150/75 ohm connections
(Factory shipped 150 ohms)
Maximum input level: -30 dbm
SIGNAL OUTPUTS
Rated output +40 dbm (10 watts)
Output impedance -600 /150/8 ohms
(Factory shipped 600 ohms)
TRANSISTOR COMPLEMENT
4
2
OPERATING CONDITIONS
Maximum ambient temperature -130 F (55 C)
Maximum humidity -95 percent
ELECTRICAL CONNECTIONS
Signal --One amphenol 8 -pin blue ribbon connector
Power One ground type a -c connector
-
1
General Electric 2N508
General Electric 2N1925
Sylvania 2N214
2
1
DELCO 2N553
DELCO 2N456A
HOW TO ORDER
When ordering, please specify: Type BA -34 -A plug in transistorized monitor amplifier.
ACCESSORIES
SAFETY PROVISIONS
No voltage is applied until the amplifier is plugged into its
mating sockets. The amplifier is equipped with an ON -OFF
switch, and the power transformer primary is fused.
Type FA -50 -A shelf (can also mount the Type BA-
25-A and Type BA -20 -A pre -amplifiers).
Type FA -35 -G bridging volume control.
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www.americanradiohistory.com
Amplifiers
AUDIO
A -c Powered Program /Monitor
Amplifier
Page A29
Type BA -14 -A
A -c powered program m3nitor amplifi3r,
T
pe BA -14 -A
FEATURES
Versatile
May be connected for matching or bridging input
Provides both line and voice -coil outputs
Can be connected for either program or monitor service
Has multi- impedance inputs and outputs
Will operate direct from a microphone or a line
High gain program or monitor amplifier
60 db of program matching gain; 36 db of program
bridging gain
105 db of monitor gain (unloaded input); 75 db of
monitor bridging gain
Compact
6%-inch height and
7 -inch width permit two amplifiers
to be mounted side -by -side on one shelf in 7 inches of
vertical rack space
Plug -in constuction and small height permit easy
removal for maintenance or service type change
All exte nal connections are made on two 10 -pin Jones
plugs and sockets. Input connections (including fixed
bridging pad) are made on one "2400" series plug,
while a -c power and output connections are made on
second "2400" series Jones plug. Mating sockets are
mounted on accessory shelf
Contains built-in power supply
Only 105 to 125 volts, 60- cycle,
this
a -c
needed to power
amplifier
Uses readily available low cost, low noise tubes
Amplifier uses three 5879's, either two 6V6's or two
5881's, and a 5U4GA. 6V6's are used in program
service, 5881's may be used for increased power in
monitor service
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Amplifiers
A -c Powered Program /Monitor
Page A30
Amplifier
Type BA -14 -A
Rated at 10 -watt output in monitor use; 4 -watt output in program use
Magnetically and electrostatically shielded transformers effectively prevent hum pickup in this and
adjacent medium or high level equipment
Stability improved through use of negative feedback.
Tertiary winding of output transformer supplies negative feedback to cathode of second stage
Excellent frequency response with low distortion
Program amplifier:
db 30- 15,000 cps
30 dbm output less than 0.5 percent harmonic distortion (50- 15,000
f
1
tl db 30-
cps)
Monitor amplifier:
15,000 cps
+40 dbm output
11/2
percent
harmonic distortion
Continuous log taper volume control with db markings furnished and mounted on amplifier
Precision step attenuator may be substituted by broad-
program amplifier in the program channel of speech
input systems.
This unit contains its own built -in power supply and
is intended for shelf mounting in an audio rack.
Simple, easily made internal connections and interchangeable tubes permit this amplifier to be quickly
converted from program -to- monitor service, or vice versa.
DESCRIPTION
The General Electric Type BA -14 -A program
monitor amplifier is a four -stage, a -c powered unit
designed to operate from either microphone or line
level signals and to furnish power to drive either program lines or one or more speakers.
Either matching inputs of 600 250 /150/30 ohms or
a 10,000 -ohm bridging input are available for matching or bridging any standard broadcast source impedance.
caster, if desired. (See Electrical Specifications -Gain
Control)
Variable frequency response made by internal adjustment, if desired
APPLICATION
The General Electric Type BA -14 -A program/
monitoring amplifier is a versatile, dual-purpose audio
amplifier designed to serve as a program or line
amplifier, or as a general -purpose monitoring amplifier
in radio and television stations, in recording studios,
and in motion picture studios.
When connected as a program amplifier it may be
used as a program or main amplifier, an isolation or
bridging amplifier, a line amplifier, for medium power
monitoring or as a cuing or audition amplifier.
When connected for monitoring service, it may be
used as a monitor amplifier, bridging program or other
lines to furnish power for studio speakers; a control to-studio talkback amplifier, where the talkback
microphone is fed into the Type BA -14 -A without pre amplification, a transcription cuing or audition amplifier (again without preamplification) ; or an emergency
Amplifiers Type BA -14 -A mounted in FA-23-C shelf
The output of the amplifier may be used to drive a
2 ohm voice -coil loudspeaker. Separate windings are used for the program
and voice -coil sections of the output transformer, thus
it is possible to use both speaker and line feed simultaneously (for low or medium level monitoring) if
required. Negative feedback is supplied from a tertiary
winding of the output transformer back to the cathode
of the second stage.
The complete amplifier includes only four stages.*
The first and second stages are conventionally connected 5879 pentode tubes. The third stage, also using
a 5879 type tube, serves as a phase -splitter driving the
push -pull output stage. When connected for program
service, two 6V6 tubes are used in the output stage.
However, when connected for monitoring service,
additional power may be gained if 5881 type tubes are
substituted for the two 6V6 tubes. A 5U4GA is used
as a rectifier.
600, 150 line and or an 8
Rear view of
amplifier Type BA -14 -A showing
plug -in construction
In program service, the first stage is by- passed and the tube
omitted from the socket.
Amplifiers
Page A31
AUDIO
A -c Powered Program /Monitor Program
Type BA -14 -A
Changes from program to monitor service or vice versa are easily made by changing five jumper straps
located on easily accessible terminal boards under the
chassis. These connections cut in or by -pass the first
stage and change the voltages supplied to the tubes.
Impedance changes are made in the customary
manner on the transformer terminals. As shipped, the
amplifier is connected for program service with a 600 ohm input, an output of 600 ohms and 8 ohms, and
minus the first -stage tube which is by- passed. For
monitor purposes a tube kit (7145567), consisting of
the first -stage 5879 and two 5881 output tubes, is
available as an accessory item.
Frequency response and noise and distortion measurements for program and monitor services may be
found under ELECTRICAL SPECIFICATIONS.
MECHANICAL SPECIFICATIONS
UNITS
One Type BA -14 -A program monitor amplifier, equipped
with an Allen- Bradley potentiometer.
DIMENSIONS
Depth
Height
inches
6% inches
13
Weight
Width
20 lbs
7! inches
MOUNTING
Each amplifier mounts in an Type FA -23 -C shelf (accessory).
Two amplifiers may be mounted in this shelf which, in turn,
may be mounted in a Type PR -1 -A or other standard EIA
Cabinet Rack. When so mounted, the rear of the amplifier
plugs into two Jones "2400" series mating sockets on the
Type FA -23 -C shelf. These two plugs handle all input,
output and power connections to this unit. The Type FA23-C shelf includes four Jones sockets, spacer bar, and two
knobs and shaft extensions.
OPERATING CONDITIONS
Maximum room ambient temperature- continuous opera113 F (45 C).
tion
percent of annual
Maximum room ambient temperature
122 F (50 C).
operating hours
Maximum cabinet ambient temperature-continuous opera122 F (50 C).
tion
Maximum cabinet ambient temperature -5 percent of
140 F (60 C).
annual operating hours
95 percent.
Maximum relative humidity
-5
.z,
IST
STAGE
WHE N
BA -14-A
IS
ELECTRICAL CONNECTIONS
Power and Signal
Two 10 -pin, "2400" series Jones plugs (furnished on amplifier) mating to two 10 -pin, "2400" series Jones sockets
mounted on Type FA -23 -C shelf (accessory).
SAFETY PROVISIONS
No voltage applied until amplifier is plugged into mating
source. Amplifier is equipped with ON -OFF switch and red
jewel indicator light. Power transformer primary is fused.
No exposed voltages.
ELECTRICAL SPECIFICATIONS
Type of Circuit
PROGRAM SERVICE
Amplifier consists of a four -stage amplifier with the first
stage by- passed. The input transformer is connected to the
grid volume control of the second stage; said stage using a
Type 5879 tube, pentode connected. The third stage, also a
Type 5879, serves as a phase-splitter which, in turn, drives
the two 6V6 tubes in the push-pull output stage. 15 db of
negative feedback is supplied from the tertiary winding of
the output transformer back to the second -stage cathode.
A 5U4GA is used as a rectifier.
MONITOR SERVICE
In monitor service, the four stages of the amplifier are used
to develop additional gain. Power output is increased by the
change in plate voltage and substitution of higher power
output tubes. The first two stages are conventionally connected pentode tubes of the 5879 type. The third stage,
utilizing a 5879, serves as a phase -splitter which, in turn,
drives two Type 5881 tubes in the push -pull output stage.
Type 6V6 tubes may be used in place of the Type 5881 tubes
with a slight reduction in power output. A Type 5U4GA tube
serves as the rectifier. 10 db of negative feedback from the
output transformer tertiary winding is supplied to the
cathode of the second stage.
Performance
PROGRAM SERVICE
MONITOR SERVICE
FREQUENCY
RESPONSE
+30 dbm out,
+40 dbm out (10
watts), 1 db 30 to
1
db 30 to 15,000
cycles per second.
INPUT
STAGE
PUSH
PHASE
400-.
INVERTER-0"
A
15,000 cycles per
second.
PULL
OUTPUT
MONITOR
Block diagram of program monitor amplifier Type BA -14 -A, shown connected as
www.americanradiohistory.com
a
program amplifier
Amplifiers
A -c Powered Program /Monitor
Page A32
Amplifier
Type BA -14 -A
Performance
PROGRAM SERVICE
MONITOR SERVICE
Performance
(cont'd)
Matching: 60 db
Bridging: 36 db
(for 600 -ohm terminated source).
GAIN
watts
OUTPUT
4
HARMONIC
+30 dbm out
50- 15,000 cps less
than 0.5 percent.
DISTORTION
30 cycles -0.75
percent.
Unloaded transformer input: 105 db.
Bridging input: 75
db (supplied with
fixed bridging resistor on Jones
Plug ).
Input stage bypassed: +40 dbm
out
Unloaded input:
66 db
Loaded input:
60 db
Bridging input:
36 db
10
-
53 dbm or less,
unweighted.
Noise remains
constant regardless of position
of gain control.
-
18 dbm at maximum gain. Volume control set
for 20 db loss.
noise level will be
-30 dbm.
Low gain monitor
-30 dbm.
MAXIMUM
0
dbm.
INPUT
BRIDGING
INPUT
24
dbtn.
-35
dbm as high
gain monitor.
0 dbm as low gain
monitor.
dbm as high
gain monitor.
I-30 dbm as low
gain monitor with
fixed resistors.
+40 dbm as low
gain monitor with
FA -35 -G bridging
volume control.
5
Input Impedances
SOURCE IMPEDANCES
MATCHING
MONITOR SERVICE
0
to 1000 ohms,
terminated resistive
circuits, balanced
or unbalanced.
0
600 250 150,30
600,250 150 30
ohms or unloaded
transformer, balanced or unblanced.
10,000 ohms,
balanced or
unbalanced.
600 250/150,30
ohms, balanced or
unbalanced.
600/250/150/30
ohms, balanced or
unbalanced.
to 1000 ohms
terminated resistive
circuits, balanced
or unbalanced.
INPUT IMPEDANCES
Matching
ohms, balanced
or unbalanced.
Bridging
10,000 ohms,
balanced or
unbalanced.
Output Impedances
SPEAKER
600/150 ohms.
8/2 ohms.
600/150 ohms.
8/2 ohms.
Gain Control*
Log taper pctenti-
Log taper potenti-
LINE
ometer continuously variable
attenuation from
to infinity.
*
ometer continuously variable
0
attenuation from
to infinity.
0
The broadcaster may substitute 500,000 -ohm Daven attenuator
CP- 130 -Y, 2 db 'step 30 step, for the gain control furnished,
if desired.
Input Power
105 115 125 volts, a -c, 50/60 cycles, single phase, 85
watts
Tube Complement
Amplifier is shipped connected for program service and is
equipped with tubes for this type service. For monitor service,
see accessory listing for monitor service tube kit.
Program service
Monitor service
INPUT LEVEL
MATCHING
Bridging
-
30- 15,000 cps 1! 1 percent.
30- 15,000 cps less
than 1 percent.
+30 dbm out,
signal to noise
ratio is 83 db.
watts
+36 dbm out
30- 15,000 cps
1 percent
+40 dbm out
+36 dbm out
NOISE
PROGRAM SERVICE
(cont'd)
-5879
-6V6
1 -5U4GA
3 -5879
2
2
2
1
-5881
-5U4GA
HOW TO ORDER
When ordering please specify:
General Electric Type BA -14 -A program
monitor amplifier. (The type number indudes the amplifier connected for program
service, a set of operating tubes for program
service, and an installation and instruction
book.)
ACCESSORIES
7145567 -Monitor tube kit (consisting of
1
-5879
tube and 2 -5881 tubes).
FA -23 -C -Shelf with four mating Jones sockets, two
knobs, and two extension shafts. Shelf will
mount two Type BA -14 -A amplifiers.
Amplifiers
AUDIO
Pre -amplifier
Page A33
Type BA -20 -A
Pre
-amplifier Type BA -20 -A
FEATURES
Small and compact
Eight units plus eight Type FA -47 -A line -to -line
coils can be mounted in one 3'.%4-inch high rack mounted shelf
50 or 40 db gain
WHERE TO USE
The General Electric Type BA -20 -A pre -amplifier is
a high-fidelity, plug -in pre -amplifier assembly designed to raise the level of microphone outputs to
mixer level for broadcast applications. The use of
printed wiring and complete transistorization makes
the unit compact and easy to install and maintain.
The Type BA -20 -A pre -amplifier is designed for use
in custom console or audio systems, using transistor
amplifiers Types BA -22 -A, BA -24 -A, or BA -28 -A.
Power for the operation of these pre- amplifiers may
be obtained from the Type BP -20 -A transistor power
supply or from any other well filtered 25 -volt d -c
supply.
DESCRIPTION
The General Electric Type BA -20 -A pre -amplifier is
a complete, plug -in, transistor pre -amplifier assembly.
The pre -amplifier is constructed on a fiberglas
printed -wire board. The input, output, and power connections are made by means of a 13 -pin connector
assembly which is staked and soldered to the circuit
board.
MECHANICAL SPECIFICATIONS
DIMENSIONS
Height
Length
2
inches
inches
51 2
Width
Weight
2% inches
6 ounces
MOUNTING
The 13 -pin connector of the pre -amplifier is inserted into a
receptacle of the Type FA -49 -A shelf. The accessory connector,
G -E drawing C- 7777466 -P1, is required if the pre- amplifier is to
be mounted in any other type of installation.
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Amplifiers
Page A34
Pre -amplifier
Type BA -20 -A
OPERATING CONDITIONS
SIGNAL OUTPUT
Maximum room ambient temperature continuous, 95 F (35 C
Maximum cabinet ambient temperature continuous I22F
(50 C)
Maximum room ambient temperature
(45 C
5
percent of time, 122 F
I
Maximum cabinet ambient temperature
131 F (55 C
Maximum relative humidity
5
percent of time,
95 percent
Between 300 and 1000 ohms unbalanced. A balanced output
may be obtained by use of accessory Type FA -47 -A line -to -line coil.
POWER INPUT
25
volts d -c at
All electrical connections are made through a 13 -pin mounted
at one end of the printed wire board.
SAFETY PROVISIONS
No power is applied to the unit unless it is plugged into its
mating socket. The maximum voltage applied to the unit is
25 volts d -c.
m.a.
CONTROLS
Accessory
ELECTRICAL CONNECTIONS
8
carbon potentiometer.
INTERCHANGEABILITY
This amplifier is not
interchangeable with any existing unit.
TRANSISTOR COMPLEMENT
3
1
General Electric 2N324 transistors
General Electric 2N320 transistor
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response
1 db 50- 15,000 C.P.S.
Gain -50 db as shipped. May be set for 40 db gain by modification.
Distortion Less than 0.5 percent rated output levels.
Noise - Equivalent to - 120 dbm at the input, i.e. a 60 db
S N ratio with
-60 dbm from a microphone. Measures 60
.lb below a
10 dbm output level.
SIGNAL INPUTS
Source Impedance 50 150 250 600 ohms balanced or unbalanced.
Input Impedance -unloaded transformer.
HOW TO ORDER
When ordering please specify:
General Electric Type BA -14 -A pre- amplifier.
ACCESSORIES
Type FA -49 -A shelf
Type FA -47 -A line -to -line coil
7777466P1 receptacle
2R74P25 potentiometer
Pre -amplifier, Type BA -20 -A (top
view)
Amplifiers
AUDIO
Transistor Pre -amplifier Module
Page A35
Type BA -21 -A, Plug -in
Preamplifier module, Type
FEATURES
All transistor -no tubes in the circuitry
Plug -in construction for ease in maintenance
Space saving -small, compact, light weight
Low voltage -low power drain
Modular construction -amplifier, Daven fader,
mixer key, and front panel make up complete
plug -in unit
Fiberglas wire board
BA21A
coupled to the third stage which is directly coupled to
the emitter -follower output stage. An interstage gain
control is located between the second and third stages.
The unbalanced 600 -ohm output of the amplifier
drives a mixer bus.
MECHANICAL SPECIFICATIONS
UNITS
Type number covers the amplifier assembly, a set of transistors,
a set of installation and operating instructions.
and
DIMENSIONS
Front Panel
WHERE TO USE
The General Electric Type BA -21 -A transistor preamplifier module provides the gain necessary to raise
the audio signal from a microphone to a level high
enough to feed a mixer bus. This pre -amplifier is designed for use in the Type BC -21 -A audio console or
other custom -console systems employing transistor
amplifiers.
Height
4 ,'¿ inch
Length
9
I
, inch
Width
3
Weight
inch
13
MOUNTING
Unit plugs into Type BC -21 -A audio console or
mounting arrangement using a 13 -pin Elco receptacle.
Max room ambient temperature, cont. 95 F (35 C
Max cabinet ambient temperature, cont. 122 F (50 C
Max room ambient temperature, 5 percent of time,
similar
)
Max cabinet ambient temperature,
The General Electric Type BA -21 -A transistor preamplifier consists of a plug -in audio unit of excellent
broadcast quality which includes the amplifier chassis,
etched -front panel, Daven step attenuator, three position output -lever switch, and a mounting frame.
This amplifier is composed of four transistor stages.
The first and second stages are directly coupled in a
configuration known as the Darlington compound
connection. The second stage is then capacitively
a
OPERATING CONDITIONS
(45 C
DESCRIPTION
Slope
45 degrees
lbs
5
113 F
percent of time,
131
F
(55 CI
Max relative humidity, 95 percent
ELECTRICAL CONNECTIONS
All electrical connections are made through
mounted at one end of the printed wire board.
a
13 -pin
plug
SAFETY PROVISIONS
No power is applied to the unit unless it is plugged into its
mating socket. When the unit is plugged in and console closed
there is no exposed voltage. The maximum voltage applied to
the unit is 25 volts d -c.
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Amplifiers
Transistor Pre -amplifier Module
Page A36
Type BA -21 -A, Plug -in
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response: I db 50- 15,000 cps.
Gain: 50 db (may be modified for 40 db if desired).
Distortion: % percent or less at rated output level.
Noise: -70 dbm
POWER REQUIREMENTS
25
TRANSISTOR COMPLEMENT
3 2N324 General Electric
1
-2N320 General Electric
COMPLIANCE
Complies with all applicable FCC and EIA specifications.
volts d -c at 8 ma
HOW TO ORDER
SIGNAL INPUTS
Levels (Max):
with amplifier connected for 50 db of gain.
-20 db with amplifier connected for 40 db of gain.
Impedances:
Input: Unloaded transformer
Source: 50/150/250/600 ohms balanced or unbalanced.
-35 db
SIGNAL OUTPUT
-10 dbm;
impedance between 300 and 1000 ohms (nominally
600 ohms) unbalanced.
CONTROLS
Daven type, adjustable in
2
db steps, no detents.
When ordering please specify: Type BA -21 -A
transistor pre -amplifier (requires external power sup-
ply).
ACCESSORIES
Type FA -47 -A line -to -line transformer will provide
a balanced 150 or 600 output from Type BA -21 -A
pre -amplifier module.
Type BP -20 -A 25 -volt transistor power supply
(regulated).
7777466P4 ELCO 13 -pin receptacle.
AUDIO
Amplifiers
Plug -in Pre -amplifier
Page A37
Type BA -1 -H
FEATURES
Plug -in construction permits easy removal for
servicing
Small. compact design. Six of these amplifiers can
be mounted in 7 -inch of rack space
Simple two -stage circuit using printed -wire board
makes parts easy to locate for maintenance
Excellent plug -in contact efficiency. Unit uses
Cinch -Jones "2400" series plugs
Tubes are shielded by easily removed tube shields
Transformers are of hum -bucking coil construction
with magnetically shielded cases
Chassis provides mounting hole to accommodate
Type FA -35 -G bridging volume control
Uniformity of performance assured by use of
printed -wireboard
WHERE TO USE
The General Electric Type BA -1 -H plug -in preamplifier is designed for use as a microphone pre-amplifier or as a booster amplifier between mixer bus and
the program amplifier of a studio -audio system. It can
also be used as an isolation amplifier when provided
with a suitable bridging resistance, such as Type FA35-G bridging volume control.
This pre -amplifier, when used in conjunction with
Type BA -12 -C plug -in program monitor amplifier,
makes it possible to assemble a complete studio -audio
system employing only two basic amplifier types.
DESCRIPTION
The Type BA -1 -H plug -in pre -amplifier consists of a
single plug -in unit that utilizes a printed -wire board on
which are assembled all the amplifier components.
This assembly is mounted in a wrap- around frame
incorporating a ten -pin Cinch -Jones "2400" series
plug.
Electrically, the Type BA -1 -H consists of two resistance coupled stages using Type 5879 tubes. A feedback loop is used around the two stages. Specially
designed input and output transformers with hum bucking coil construction and alloy shields are used.
An unloaded transformer input is employed to give
maximum gain and optimum signal -to -noise ratio from
high -quality broadcast microphones.
A Type FA -35 -G bridging volume control is available as an accessory. This control may be mounted in
a hole which is available for this purpose on the Type
BA -1 -H amplifier. When mounted, this control provides a 10,000 -ohm input impedance for use as a
bridging or continuously variable -input volume con-
trol.
Plug -in pre -amplifier, Type BA -1 -H
MECHANICAL SPECIFICATIONS
UNITS
Type number covers single plug -in assembly.
DIMENSIONS
Width
Height 4 inches
Length 10% inches
Weight
2176
inches
2' , lbs
MOUNTING
Six of these pre- amplifiers or three pre -amplifiers and one
Type BP -10 -B plug -in power supply can be mounted on a Type
FA -23 -B shelf (accessory) for rack mounting. Up to seven preamplifiers can be mounted in a Type BC -11 -A audio console.
OPERATING CONDITIONS
Maximum cabinet ambient temperature: 130 F (55 C)
Maximum relative humidity:
95 percent
ELECTRICAL CONNECTIONS
All connections are made via a 10 -pin "2400" series Cinch Jones plug, which is the standard plug used on all our plug -in
units.
SAFETY PROVISIONS
No B+ power is applied to the unit unless it is plugged into
its mating connector. The exposed soldered eyelet points on the
top side of the board are protected with an insulating coating of
resin varnish.
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response:
Gain:
t
1
db 50- 15,000 cps.
40 db
Amplifiers
Plug -in Pre -amplifier
Page A38
Type BA -1 -H
Harmonic Distortion:
Noise
0.5 percent or less at +18 dbm,
50- 15,000 cps.
80 dbm or less.
POWER REQUIREMENTS
0.3 ma at 6.3 volts a -c (filament power)
Filaments biased at +20 to +50 volts d -c (supplied by BP10-B power supply).
SIGNAL INPUTS
Input Impedance
Source Impedance:
Unloaded transformer.
30 150 250 600 ohms connections
150 ohms as shipped.;
(
SIGNAL OUTPUTS
Rated output, +18 dbm; output impedance, 600 150 ohms;
600 ohms as shipped.
TUBE COMPLEMENT
2
Type 5879
INTERCHANGEABILITY
Electrically and mechanically interchangeable with
previous Type BA -1 -F plug -in pre -amplifier.
COMPLIANCE
Complies with all applicable FCC and RETMA
specifications.
HOW TO ORDER
When ordering, please specify: Type BA -1 -H plug in pre- amplifier (requires an external power supply).
ACCESSORIES
Type BP -10 -B plug -in power supply, for Types
BA -1 -H's and or BA- 12 -C's. (Type BP -10 -B uses 200
watts at 110 volts a -c and will supply power for 25
Type BA -1 -H pre -amplifiers or three Type BA -12 -C
program monitoring amplifiers.)
Type FA -23 -B shelf, for mounting various plug -in
amplifiers. The Type FA -23 -B shelf requires seven
inches of vertical -rack space, and will accommodate six
Type BA -1 -H pre -amplifiers, or four Type BA -12 -C
program monitoring amplifiers, or Type BA -9 -A unilevel amplifiers; or two Type BP -10 -B power supplies
or combinations of these plug -in units.
Type FA -35 -G bridging volume control, for use
with Type BA -1 -H and BA -12 -C amplifiers. It is
designed to convert a 600 -ohm amplifier input to a
10,000 -ohm balanced- bridging service and may be
used on line levels up to +40 dbm. When used with
the Type BA -1 -F it is connected ahead of the input
transformer.
AUDIO
Amplifiers
Transistor Plug -in Pre -amplifier
Page A39
Type BA -25 -B
Transistor plug -in pre -amplifier, Type BA -25 -B
FEATURES
Plug -in construction
permits easy removal
for
servicing
Small, compact design. Ten of these amplifiers can
be mounted in 31/2 inches of rack space
Amplifier is assembled on a rugged printed -wire
fiberglas board
Chassis provides mounting hole to accommodate
the General Electric Type FA -35 -G bridging volume
control or an interstage gain control
Uniformity of performance assured by use of
printed wireboard
The input stage is unloaded to provide maximum
gain and optimum signal -to -noise ratio from high
quality broadcast microphones.
Circuit provisions have been included in the amplifier for the installation of an optional interstage gain
control. Either an interstage gain control, or a conventional bridging gain control such as the Type FA35-G, may be mounted on bracket which is part of
the amplifier's basic chassis.
MECHANICAL SPECIFICATIONS
UNITS
Type number covers single plug -in assembly.
WHERE TO USE
DIMENSIONS
The General Electric Type BA -25 -B plug -in pre
amplifier is designed for use as a microphone preamplifier or as a booster amplifier between mixer bus
and the program amplifier of a studio -audio system. It
can also be used as an isolation amplifier when provided with a suitable bridging resistance, such as Type
FA -35 -G bridging volume control.
This pre -amplifier, when used in conjunction with
the General Electric Type BA -22 -A plug -in program
amplifier, makes it possible to assemble a complete
studio -audio system employing only two basic amplifier types.
Height
Length
2 74i
11 Vi
inches
inches
1
inches
lb, 5 oz
K
Plug -in mounting. Ten of these pre -amplifiers can be mounted
on a Type FA -50 -A shelf (accessory) for rack mounting.
OPERATING CONDITIONS
Maximum cabinet ambient temperature: 130 F (55 C
Maximum relative humidity:
95 percent
ELECTRICAL CONNECTIONS
All connections are made via a 9 -pin Elco plug, which is the
standard plug used on all our plug -in units.
SAFETY
PROVISIONS
is applied
mating connector.
The General Electric Type BA -25 -B transistorized
plug -in pre -amplifier consists of a single plug -in unit.
This unit is composed of an aluminum chassis and a
fiberglas printed -wire board. All amplifier components,
including the plug -in connector, except the input and
output transformers are assembled on the fiberglas
wire board. The two transformers mount directly to
the aluminum chassis.
Electrically, the Type BA -25 -B amplifier circuit is
composed of two common emitter gain stages followed
by a four transistor compound-connected single -ended
push -pull output stage. All transistors plug into
sockets on the amplifier board.
15
Weight
MOUNTING
No power
DESCRIPTION
Width
to the unit unless it is plugged into its
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response:
Gain:
I2 db 50- 15,000 cps and *1 db
30 to 15,000 cps
46 db
HARMONIC DISTORTION
0.5 percent or less at +18 dbm, 30 15,000 cps
NOISE
120
dbm related to input
POWER REQUIREMENTS
18 MA
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at 25 -volt, d -c
Amplifiers
Transistor Plug -in Pre -amplifier
Page A40
Type BA -25 -B
SIGNAL INPUTS
Input Impedance:
Source Impedance:
Unloaded transformer.
150 250 600 ohms connections (150
ohms as shipped).
SIGNAL OUTPUTS
Rated output, +18 dbm; output impedance, 600,'150 ohms;
600 ohms as shipped.
TRANSISTOR COMPLEMENT
2
1
3
General Electric
SYL
RCA
2N508
2N214
2N270
COMPLIANCE
Complies with all applicable FCC and EIA specifications.
HOW TO ORDER
When ordering, please specify: General Electric
Type BA -25 -B plug -in pre -amplifier (requires an
external power supply).
ACCESSORIES
Type BP -20 -A power supply, for Type BA -25 -B
and ï or Type BA -24 -A.
Type FA -50 -A shelf, for mounting various plug -in
amplifiers. The Type FA -50 -A shelf requires 3
inches of vertical rack space, and will accommodate
10 Type BA -25 -B pre -amplifiers, or Type 4BA -34 -A
monitor amplifiers.
Type FA -35 -G bridging volume control, for use with
Type BA -25 -A amplifiers. It is designed to convert a
600 -ohm amplifier input to a 10,000 -ohm balanced bridging service and may be used on line levels up to
+40 dbm. When used with the Type BA -25 -B it is
connected ahead of the input transformer.
Amplifiers
AUDIO
Plug -in Program /Monitoring Amplifier
Page A41
Type BA -12 -C
Plug -in program monitoring amplifier, Type BA -12 -C
FEATURES
Small, compact design. Four of these amplifiers can
be mounted in seven inches of rack space
Plug -in construction with point -to -point wiring
makes maintenance extremely easy
Only two tube -types used
Easy removal for servicing. Uses Jones "2400"
series plug
Chassis punched for addition of bridging controls
and metering switches
No shock hazard. Voltage is applied to the u lit only
when plugged into a mating source and when so
plugged in, no voltage is exposed
Fulfills all medium and high -level audio system
requirements. Toggle switch allows selec+ ion of
56- or 71 -db gain
WHERE TO USE
The General Electric Type BA -12 -C, plug -1n program /monitoring amplifier is a high fidelity, compact, fixed gain, plug -in audio unit, recommended for
use as a program, line, monitoring or isolation amplifier.
When the switch is in the high position, the amplifier
may be used as a monitor amplifier with a gain of 71
db. In this application an output level of +39 dbm
(8 watts) is possible with a distortion figure of less than
3 percent at maximum input level of -32 dbm.
Electrically the Type BA -12 -C amplifier consists of
a 5879 pentode input stage plus a triode- connected
5879 used as a split -load phase inverter and two 6V6
tubes in the push -pull output stage. Feedback from a
tertiary winding on the output transformer is fed to
the cathode of the first stage. For high -gain applications, the "HI" position of the switch decreases the
feedback by 15 db.
Holes are provided on the chassis for installation of
an accessory Type FA -35 -G bridging volume control
and two tube metering switches if such are desired.
The Type BA -12 -C amplifier is equipped with a
male, 10 -pin "2400" series Jones plug for mating use in
the General Electric Type BC -11 -A console. It may
also be mounted on an accessory Type FA -22 -E tray
with mating receptacle for rack use. When so mounted,
the tray and amplifier combination is usually mounted
on a Type FA -23 -A standard cabinet -rack mounting
shelf (accessory). Power can then be obtained from a
rack - mounted Type BP -10 -B power supply.
DESCRIPTION
The General Electric Type BA -12 -C plug -in program 'monitor amplifier is a dual -purpose amplifier.
By means of a switch, located on the chassis top, this
amplifier may be instantly changed from a line
amplifier to an 8 -watt monitor amplifier.
With the switch set in low position, the amplifier
serves as a program or line amplifier. In this position
the amplifier has a gain of 56 db. With an output level
of +30 dbm, the distortion is less than one -half of one
percent with a maximum input of 26 dbm.
-
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth
Height
10; °4 inches
53.í inches
Width
3/z inches
Weight
6 lbs
MOUNTING
Each Type BA-12 -C amplifier mounts on a Type FA -22 -E
tray. Four of these trays mount on one Type FA -23 -A shelf,
occupying seven inches (four rack units) of cabinet space.
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Amplifiers
Page A42
Plug -in Program /Monitoring Amplifier
Type BA -12 -C
Output Level and
Distortion:
OPERATING CONDITIONS
Maximum ambient temperature:
Maximum relative humidity:
113 F (45 C)
95 percent
SAFETY PROVISIONS
Voltage is applied to the unit only when it is plugged into
mating source and when so plugged, no voltage is exposed.
a
ELECTRICAL SPECIFICATIONS
Type of Circuit
Consits of a 5879 pentode input stage plus a triode
connected 5879 used as a split -load phase inverter and
two Type 6V6 tubes as the push -pull output. Feedback is used from a tertiary winding on the output
transformer to the cathode of the input stage. For
high gain applications, a switch is provided to decrease
the feedback by 15 db.
PERFORMANCE
Program Amplifier (low gain position)
Frequency Range:
Gain:
Output Level and
Distortion
Output Noise:
50- 15,000 cps.
56 db
1
db
(1 watt) ! 2 percent or less
26
distortion (maximum input
dbm)
+39 dbm (8 watts) 1 percent or less
distortion (maximum input -17
dbm)
Less than -60 dbm
+30 dbm
71
tubes, and increasing the
db
Plug -in program monitoring amplifiers, Type BA -12 -C plug plug in pre -amplifiers, Type BA -1 -F mounted in broadcast shelf,
Type FA -23 -A
B+ supply voltage.
SIGNAL INPUTS
Input Impedance:
Source Impedance:
Unloaded transformer
600.'150 ohms; 600 ohms as shipped
POWER INPUTS
Filaments:
Bias:
B+ Requirement:
1.2 amps at 6.3 volts a -c
Biased at +20 to +50 volts d -c
88 ma at 300 volts d -c (at 8 watts output)
OUTPUTS
Output impedance, 600'150 ohms; 600 ohms as shipped.
TUBE COMPLEMENT
2
Monitoring Amplifier (high gain position)
50- 15,000 cps. *1!,L cb
Frequency Range:
Gain:
For high level loudspeaker applications, the Type BA -12 -C can
be modified to give 15 watts output by using Type 6L6 or 5881
2
t
+39 dbm (8 watts) 3 percent or less
distortion (maximum input -32
dbml
Type 5879 (input and phase inverter
Type 6V6 (push -pull output
(Type 6L6 or Type 5881 tubes may be used to obtain higher
power output when desired)
)
I
HOW TO ORDER
When ordering, please specify:
Type BA -12 -C plug -in program monitoring amplifier (requires an external power supply).
ACCESSORIES
Type FA -22 -E tray, for mounting Type BA -12 -C.
Type BP -10 -B plug-in power supply, for BA -1 -F's
and or BA- 12 -C's. (Type BP-10 -B uses 200 watts at
110 volts a -c and will supply power for 25 Type BA1-F pre -amplifiers or three Type BA -12 -C program
monitoring amplifiers.)
Type FA -23 -A shelf, for monting plug -in units with
trays. (Type FA -23 -A occupies seven inches (four
units of rack height) in a Type PR -1 -A Cabinet Rack
and will accommodate six pre -amps, Type BA -1 -F,
with trays, four Type BA -12 -C program monitoring
amplifiers, with trays or two Type BP -10 -B power
supplies, with trays.)
Type FA -35 -G, bridging volume control. (Bridging
volume control for use with Type BA -1 -F and Type
BA -12 -C amplifiers. It is designed to convert a 600 ohms amplifier input to a 10,000 -ohm balanced bridging service and may be used in line levels up to
+40 dbm.)
Amplifiers
AUDIO
Transistor Program Amplifier
Page A43
Type BA -22 -A, Plug -in
Program Amplifier Type BA -22 -A
FEATURES
All plug -in transistors no tubes in the circuitry
Low voltage low power drain
Plug -in construction for ease in maintenance
Space saving small, compact, lightweight
Fiberglas wire board
WHERE TO USE
The General Electric Type B -22 -A transistor program amplifier provides the gain necessary to raise an
audio signal from mixer bus level to line output level
of +24 dbm (+ 18 dbm and a 6 db pad).
This amplifier is designed for use in the Type BC21 -A audio console or any custom console employing
transistor amplifiers.
DESCRIPTION
The Type BA -22 -A transistor program amplifier is a
compact plug -in audio unit constructed on a printed
fiberglas wire board and mounted on an "L" shaped
aluminum frame.
This fine broadcast quality high fidelity amplifier
contains eight separate transistor stages. The first two
stages are coupled directly in a Darlington compound
connection. The second stage is capactively coupled to
the third stage which is directly coupled to the fourth
stage. The fourth stage is a common emitter directly
coupled to an emitter follower which is then directly
coupled to another common emitter. The latter stage
is directly coupled to a common collector Darlington
compound connected output stage. The master gain
control is connected between stages two and three.
MECHANICAL SPECIFICATIONS
Dimensions
Height
Length
www.americanradiohistory.com
4I
95
2
inches
inches
Width
Weight
434 inches
V lbs
1
Amplifiers
Page A44
Transistor Program Amplifier
Type BA -22 -A, Plug -in
MOUNTING
SIGNAL OUTPUT
This amplifier plugs into the Type BC -21 -A audio console or,
by utilizing a Type FA -48 -A shelf, up to four of these units may
be rack mounted in any standard EIA rack such as the Type
PR -1 -A equipment rack.
150 600 ohms balanced or unbalanced
ohms at +24 dbm output level.
OPERATING CONDITIONS
Max room ambient temperature, Cont. 95 F (35 C)
Max cabinet ambient temperature, Cont. 122 F (50 C
Max room ambient temperature, 5 percent of time, 113 F
(45 C
CONTROLS
Provisions are made for mounting an interstage control on the
amplifier front when required. A 750K carbon potentiometer is
recommended. When used in Type BC -21 -A audio console, a
daven, step -type control is used.
TRANSISTOR COMPLEMENT
)
Max cabinet ambient temperature,
5
percent of time,
3
131 F
4
(55 C
1
Max relative humidity, 95 percent
ELECTRICAL CONNECTIONS
All connections are made by a 9 -pin plug which
printed wire board.
is
attached to
SAFETY PROVISIONS
No power is applied to the unit unless it is plugged into its
mating socket. When the unit is plugged in and console closed
there is no exposed voltage. The maximum voltage applied to
the unit is 50 volts d -c.
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency Response: *1 db 50- 15,000 cps
Gain: 75 db matching input
Distortion: 12 percent or less at +24 db (or rated output
level
Noise:
S N
ratio of 60 db
COMPLIANCE
Complies with all applicable FCC and EIA specifications.
HOW TO ORDER
When ordering please specify: Type BA -22 -A transistor program amplifier (requires external power
supply).
Type number includes amplifier assembly, a set of
transistors and a set of installation and operating
instructions.
volts d -c at 160 ma.
SIGNAL INPUT
Transformer matching maximum input level
2N324 General Electric
-2N320 General Electric
2N553 Delco
ACCESSORIES
POWER REQUIREMENTS
50
connected for 600
27
dbm.
Program amplifier Type BA -22 -A installed in
Type FA -48 -A equipment shelf
Type BP -21 -A 50 25 volt power supply
2R74P25 750K carbon potentiometer
o
equipment shelf Type FA -48 -A
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AUDIO
Plug -in Uni -level Pre -amplifier
Amplifiers
Page A45
Type BA-1 5-A
Plug -in uni -level pre -amplifier, Type BA -15 -A
FEATURES
Versatile
Relieves operators by permitting automatic level control in any microphone channel
May be used in variety of applications in AM- FM -TVRecording studios, such as announce booths, boom mikes,
and public address systems
Controls level difference between two or more microphone signals
Automatic gain control is applied when the microphone
signal to the amplifier is -70 dbm or higher. Signals
below
70 dbm are linearly amplified
High gain -60 db vs 40 db gain for standard preamplifiers
Plug -in construction allows easy removal of preamplifiers for servicing
Small compact design. Six of these units can be
mounted in seven inches of rack space
Tubes are shielded by easily removed tube shields
Transformers are of hum -bucking coil construction
with magnetically shielded cases
Prevents blasting when two or more people are
using same microphone
Automatically adjusts audio level from close -in to
six or eight feet from microphone
WHERE TO USE
The General Electric Type BA -15 -A plug -in uni level pre -amplifier is a high -gain microphone preamplifier incorporating automatic -level control. This
device is designed to automatically control variation
in microphone signal levels. This compact plug -in unit
may be used in place of the Type BA -1 -F or Type
BA-1 -H pre- amplifiers.
Input level variations of up to 30 db may be success-
fully controlled by this pre -amplifier with only a 10 db
change in the output signal level. Such variations are
often encountered in boom microphone operation or in
other cases where the relationship between the talent
and the microphone is continuously changing. In
addition, the uni -level pre -amplifier is a high gain unit
having 60 db of gain as compared to a conventional
pre- amplifier having 40 db of gain.
DESCRIPTION
The General Electric Type BA -15 -A plug -in uni level pre- amplifier is a single plug -in chassis which
consists of a push -pull input stage (12AX7) supplying
signal to a variable gain output stage (GL- 6386).
Signal for the bias generator is supplied from the
plates of the output stage (GL6386) to a voltage
amplifier stage (GL5670) connected in push -pull. The
voltage amplifier supplies a signal to a full wave bias
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Amplifiers
Plug -in Uni -level Pre -amplifier
Page A46
Type BA -15 -A
rectifier stage (6AL5) whose output applies a bias
voltage to the control grids of the variable gain stage.
MECHANICAL SPECIFICATIONS
ELECTRICAL CONNECTIONS
All connections are made to one 2400 series Jones connector
mounted at end of chassis. The electrical connections to the Type
BA-15 -A Jones connector except for one connection are the same
as our present line of plug -in amplifiers.
UNITS
The type number covers the amplifier, one set of operating
tubes, and installation and operating instructions.
ELECTRICAL SPECIFICATIONS
DIMENSIONS
Frequency Response:
1
db 50- 12,000 and +1 -1.5 (G
15,000 cycles under any gain condition up to 30 db gain reduction.
Gain: 60 db unloaded transformer input.
Height 434 inches
Length 101 = inches
Width
21
Weight
1
I
, inches
, lbs
PERFORMANCE
The size of this unit permits it to be used with our present
line of plug -in amplifiers. The chassis size is that of the Type
BA-1 -H. It may be used to replace a Type BA -1 -F or H, or any
similar amplifier used as a microphone pre -amplifier of any studio
Harmonic Distortion: Below and up to threshold of gain
reduction 0.5 percent -50 to 15,000 cps. With 30 db gain reduction 50 to 15,000 cps 1 percent.
Output Noise: -60 dbm.
Attack Time: 1 millisecond
Recovery Time: 0.9 seconds for 63 percent recovery.
audio system.
POWER REQUIREMENTS
MECHANICAL
Six uni -level pre- amplifiers can be mounted in seven inches of
rack space using a Type FA -23 -B shelf. Plug -in construction using
a Jones 2400 series plug allows easy removal for servicing.
300 -volt d -c 25 ma approximately.
6.3 -volt a -c @ 1.30 amps +20 to +50 -volt d -c bias on filaments. 15.7 watts. (The Type BA-15 -A uses an external power
supply -suggested Type BP -10 -B power supply.I
OPERATING CONDITIONS
SIGNAL INPUTS
MOUNTING
Up to an external ambient of 45 C.
Up to 95 percent relative humidity.
Will withstand normal shipping.
Open-type construction allows natural ventilation.
-
Microphone level and up to 40 dbm with 30 db gain reduction.
Source Impedance: 30 150 /250/600 ohms.
Impedance: 150 ohms as shipped. Balanced or unbalanced.
Input Impedance: Unloaded transformer.
SIGNAL OUTPUTS
Threshold 10 dbm output 0 dbm at 30 db gain reduction.
150 600 ohms out. 600 ohms as shipped. Balanced or unbalanced.
TUBE COMPLEMENT
-12AX7
1
1- GL6386
1-6AL5
1-GL5670
HOW TO ORDER
When ordering specify:
Type BA -15 -A plug -in uni -level pre -amplifier to
consist of one amplifier; one set of operating tubes and
installation and operating instructions.
m
o
ACCESSORIES
1
-20
-SO
.75
-70
-65
-60
INPUT
SIGNAL
-55
LEVEL
-45
-50
IN
OSM
-40
1
-
Type FA -23 -B shelf (mounts six Type BA -15 -A
amplifiers)
Type BP -10 -B power supply will supply five
Type BA -15 -A amplifiers.
AUDIO
Amplifiers
Microphone Pre -amplifier
Page A47
Type BA -30 -A
Microphone pre -amplifier, Type BA -30 -A (actual size)
FEATURES
Excellent frequency response with very low distor-
DIMENSIONS
Diameter
1% inches
tion
Amplification of line noise
is considerably reduced,
since the signal is raised to a high level right near
microphone
Small size and little weight permits mounting at the
end of a microphone boom
Operates on 15- to 25 -volt, d -c at 10 ma. Use a
battery or any well -filtered power supply
New General Electric PEP (Planar Epitaxial Passivated) silicon transistors used for a high degree of
stability and ruggedness
WHERE TO USE
The General Electric Type BA -30 -A transistorized
microphone pre -amplifier is a boom microphone
booster amplifier, a desk or a stand microphone preamplifier, or a microphone -to -line amplifier for remote
applications. Gain settings of 20, 30, 40, or 56 db are
available, with the change of one feedback resistor.
With the gain set at 20 or 30 db, the level of a boom
microphone is raised to a level which allows better
control of the audio at the console. With the gain set
at 40 db, a desk or a stand microphone output is raised
to a sufficient level to feed directly into the high -level
input of an audio -control console. Two microphones
using two Type BA -30 -A preamps could be used to
feed a dual- mixing attenuator ; enabling one knob control of a stereo microphone setup. With the gain set
at 56 db gain, the Type BA -30 -A microphone preamplifier may be used to feed a telephone line directly.
DESCRIPTION
Type BA -30 -A microphone pre -amplifier consists of
a fiberglas printed- circuit board, which mounts a P3
audio connector at each end. The entire assembly is
covered by an aluminum sleeve.
The amplifier consists of three common emitter
stages, which couple to an emitter -follower output
stage. The input impedance is high to bridge the output of a 150- or 600 -ohm microphone. The output
impedance is low to feed either a 150- or 600 -ohm load.
The circuit is designed so that the signal does not
"clip" nor become distorted at low supply voltages.
For example, if the supply voltage decreases to 15 -volt,
only the gain has decreased by one -half db ; but the
distortion has not changed from its very low value.
MECHANICAL SPECIFICATIONS
Length
5N inches
Weight
4 oz
MOUNTING
Any position in the microphone line, between P3 audio connectors furnished with the unit, or any existing P3 connectors.
OPERATING CONDITIONS
Maximum ambient temperature -60 C (140 F)
Maximum relative humidity
-95 percent
ELECTRICAL CONNECTIONS
Microphone input, and line output connectors plug directly
into each end of the amplifier. Power supply connections can be
made at the base of a microphone boom or at the audio console.
No extra wires are needed. The d -c and audio share the same
wiring. The signal is coupled out through a blocking capacitor.
SAFETY PROVISIONS
Power is removed from the amplifier when the line connector is
removed. The line connector and the amplifier are keyed so that
only the amplifier can mate with the line connector. A microphone
connector is "blocked out" to prevent damage to a microphone
by d -c voltage.
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Gain: 20, 30 (factory shipped), 40, or 56 db
For gain settings of 20, 30, and 40 db
Frequency response: *1 db 30- 15,000 CPS
Distortion: ,, percent or less at rated level
Noise:
70 dbm
-
1
POWER REQUIREMENTS
15- to 25 -volt d -c at 10 ma
The following 221.,-volt batteries will give 150 hours continuous, up to 200 hours intermittent operation:
Neda No. 710
Eveready No. 763
Burgess No. 4156
SIGNAL INPUTS
levelswith amplifier connected for 20 db gain
-- 1424 db
with amplifier connected for 30 db gain
-- 3450 db
db with amplifier connected for 40 db gain
db with amplifier connected for 56 db gain
Maximum input
Impedances --
Input: High impedance
Source: 50 or 150 or 250 or 600 ohms unbalanced
SIGNAL OUTPUT
Level: +6 dbm max for all gain settings
Impedance: Low --to feed 150- or 600 -ohm load
TRANSISTOR COMPLEMENT
1
2N2195 General Electric
COMPLIANCE
Complies with all applicable FCC and EIA specifications.
UNITS
The type number covers the amplifier assembly, two Cannon
P3 line connectors, three feedback resistors, a signal -coupling
capacitor, a power supply bypass capacitor, a power supply
isolating resistor, and an instruction booklet.
HOW TO ORDER
When ordering please specify Type BA -30 -A microphone pre- amplifier. (Requires external power supply.)
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:
AUDIO
Amplifiers
Equalized Monaural/Stereo Transcription Pre -amplifier
Page A49
Type BA -23 -A
Equalized monaural /stereo transcription pre -amplifier, Type BA -23 -A, with cover (left), with cover removed (right)
FEATURES
Two complete amplifier channels
Full RIAA low- frequency response
Adjustable high- frequency response
including
RIAA position
Sufficient level to feed directly into conventional
mixer systems
Completely transistorized
Shielded output and power transformers
Output circuits are 600/150 ohms and may be run
either balanced or unbalanced
Low distortion
Built -in power supply -117/230 volts, 50/60 cycles
WHERE TO USE
The General Electric Type BA -23 -A equalized
transcription pre -amplifier is a transistorized dual
channel amplifier designed for stereo- or monaural
play -back applications.
It is designed to operate with high impedance stereo
or monaural cartridges such as the General Electric
Types VR -225, VR -1000, or other similar type cartridges. A four -position equalizer switch plus a monaural stereo output switch provide extreme operating
-
flexibility.
DESCRIPTION
The complete dual amplifier and power supply is
assembled into a single -cased unit. All signal input
and output connections are made to the unit by means
of a Jones 310 series connector. A fixed power -supply
cord is provided for power- connection purposes.
Two operating controls are provided in this design.
One is four -position switch for selecting response
characteristics. The second switch is a MONAURAL
STEREO switch which permits selection of the out-
put modes of this dual -amplifier assembly. Both controls are located inside the basic assembly. Two -inch
shafts provide adequate length for bringing the controls through the motor board.
A laminated plastic overlay plate is provided for
mounting at the operating position on the motor
board top.
The four response positions of the selector switch
are:
1. FLAT
2. RIAA
3. RIAA WITH HIGH BOOST
4. RIAA WITH HIGH ATTENUATION
The FLAT position provides essentially unequalized
high- frequency response from material recorded at a
constant velocity.
The RIAA position provides a flat response characteristic for records recorded in accordance with the
RIAA recording curve.
The RIAA HIGH BOOST position provides essentially flat RIAA equalization with a slight boost at
the high end to compensate for record wear.
The RIAA HIGH ATTENUATION position produces RIAA equalization with a reduced high end
response for use with "noisy" records.
When used as a STEREO transcription amplifier,
two separate amplifiers provide stereo outputs. When
used as a MONAURAL amplifier, the two channels
are connected together at an inter -stage point and two
identical monaural outputs are provided. This makes
it possible to play monaural recordings, with a stereo
cartridge by simply placing the MONAURAL
STEREO switch in the MON position.
Each amplifier channel is equipped with a level -set
control for balancing the output level of the two
channels. These controls are located on the plug -in
side of the pre -amplifier assembly, since they are not
normal operating controls.
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Amplifiers
Equalized Monaural /Stereo Transcription Pre -amplifier
Page A50
Type BA -23 -A
The self -contained power supply is designed to
operate from either a 117 -volt or 230 -volt 50 ' 60 -cycle
line. As normally shipped, the power supply is
strapped for 117 -volt a -c line operation.
MECHANICAL SPECIFICATIONS
7
1
2- General Electric Type 2N508 4- General Electric Type 2N525
2- General Electric Type 2N1306 1-General Electric Type 1N91
Diode
OUTPUT LEVEL
When used with the General Electric variable reluctance
cartridge, the output will be approximately -20 VU maximum
from microgroove records.
NOISE LEVEL
-
DIMENSIONS
Depth 37/8
Height
TRANSISTOR AND DIODE COMPLEMENT
inches
2 inches (excluding
switch shafts)
Width
Weight
inches
Approx 3 lb
8 oz (unpacked
--65 dbm
OUTPUT CIRCUITS
37/3
)
MOUNTING
The amplifier mounts below the turntable motor board and
the switches are designed to mount on the top of the turntable
board.
Load impedance: 600;'150 ohms
Output connections: 600 or 150 ohms - balanced, or either side.
may be grounded.
DISTORTION
percent or less, 30 to 15,000 cycles with up to
POWER INPUT
117, 230 volts, 50/60 cycles
10 watts
1
CHANNEL
GE VR- 1000 -S
CARTRIDGE USED WITH
LONDON PS -131 STEREO TEST DISC.
RESPONSE
STEREO
OF
-
FLAT
15
10
5
REL
db
RI.AA.HI BOOST-
'
0
-5
dbm.
HOW TO ORDER
When ordering, please specify:
Type BA -23 -A equalized stereo transcription preamplifier.
ELECTRICAL SPECIFICATIONS
TYPICAL
-10
output. This includes equalizing circuits.
T
-Io
-15
40
100
500
FREQUENCY
5000
1000
C
P
S.
10000
-
R I. A. A.
R.I. A.A.
HI-
ATT EN.
AUDIO
Control
Transistorized Portable Amplifier
Page A101
Type BA -26-A
Transistorized portable amplifier, Type BA -26A
FEATURES
Completely transistorized -not a tube in the circuitry
Four microphone inputs, plus a high level input.
All five inputs equipped with transformers
Regulated, self -contained 95- 135 -volt 50 60 -cycle
a -c power supply
Provisions for operating from self -contained batteries
Built -in tone generator
Provisions for paralleling portable amplifiers
Amplified cue
Small, lightweight design, weighs only 191/2 lbs
All transistors plug -in
New laminated plastic front panel for ease of write in and erase
Built -in studio quality-designed for use on AMFM-TV broadcast and recording audio applications
Carrying handle functions as
convenient operating angle
a
base to set unit at a
WHERE TO USE
The General Electric Type BA -26 -A transistorized
portable amplifier is designed for all remote or auxiliary (emergency) studio audio mixing applications in
AM -FM -TV or recording work.
Standard input and output impedances will make it
possible to operate this transistorized portable amplifier in conjunction with other makes and models of
broadcast audio equipment.
DESCRIPTION
The Type BA -26 -A transistorized portable amplifier
is suitable for use as a remote audio mixer and amplifier, capable of amplifying and mixing four microphones and one high -level source and feeding the
output to a line at a +18 dbm level. The frequency
response and distortion characteristics will be such
that it will be suitable for use on AM -FM -TV and
recording applications.
In addition to providing facilities for mixing five
sources, this transistorized portable amplifier has a
self- contained power supply and provisions for installing batteries. This will permit the operation of the
transistorized portable amplifier from either a power
line or its batteries.
A new feature includes a high -level input which
may be used for mixing in a music source or as a means
of coupling two or more Type BA -26 -A transistorized
portable amplifiers together to get additional mixing
facilities.
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Control
Transistorized Portable Amplifier
Page A102
Type BA -26 -A
Transistorized portable amplifier, Type BA -26 -A (rear cover opened)
control
1.
Hinged cover
6. Cue gain
2.
Removable plate for mounting cannon P3 type receptacles
7.
Public address feed control
3.
XLR type input connectors
8.
Dual phone jacks
-1.
High level gain control
9.
Head phone control
5.
Spring type binding posts for output
and public address connections (5)
10.
Eight -foot power cord
Control
AUDIO
Transistorized Portable Amplifier
.
Page A103
Type BA -26 -A
Transistorized portable amplifier, Type BA -26 -A (top cover removed)
11.
Meter light batteries
16.
Line ON OFF cue switch
12.
Output transformer
17.
Power check +8VU tone switch
13.
Microphone input transformer
18.
Power switch
14.
Mercury cells for amplifier battery
operation (4)
19.
Regulated
15.
Laminated "write on" panel
20.
High level input transformer
www.americanradiohistory.com
a -c power
supply
Control
Transistorized Portable Amplifier
Page A104
l
Type BA -26-A
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth 12
inches
inches
15 inches
Weight 19! 2 lb with batteries (1W2 lb less batteries)
Height
Width
7
Frequency Response *1 db 50 to 15,000 CPS
Over -all Gain 90 db 2 db
Noise 65 db below +18 dbm output level
Distortion -1 percent or less at a +18 dbm out after a 4 db
pad from 50 to 15,000
Battery operation in hours -Approximately 25 hours
Operating Temperature Range -Up to 55 5 percent of the
time, 45 continuous
POWER REQUIREMENTS
MOUNTING
Self -contained portable unit. Sets in position on four rubber
feet or may be tilted at an angle by positioning handle under
unit. Four rubber feet on the cover allow unit to sit on any
surface in the carrying position
Power Inputs
A -c Supply -95- 135 -volt, 50 '60- cycle, 225 watts (approx)
Batteries
6% -volt cells
2 112-volt flashlight cells
-4
Signal Inputs
ELECTRICAL CONNECTIONS
All connections are accessible through a spring -loaded hinged
rear cover. The connections include:
4 Microphone receptacles-- Cannon XLR-31 receptacle.
(Cannon P3 -13 may be substituted by removal of XLR -31
mounting plate.)
(Cannon
1 High -level input receptacle- Cannon XLR -31.
P3 -13 may be substituted by removal of XLR-31 mounting plate.)
i Pair of spring -loaded binding posts for output line connections
1 Spring -loaded binding post for ground terminal
1 Pair of spring -loaded binding posts for public address
2
1
output
Monitor phone output jacks
A -c cord (grounded- safety type)- adapter provided for
two -wire plug
Impedances
50/150/600 ohms balanced or unbalanced
Levels
MIC level to -25 dbm (maximum)
High Level 0 to -20 dbm
Signal Outputs
Impedance Line
Output- 150/600 ohm balanced or unbalanced
Mon. Phone Output -High Impedance output balanced
PA Output -150 ohms, balanced
Levels
Line -+18 dbm (after 4 db pad)
Mon. Phones
dbm (maximum adjustable)
PA Feed- -50 dbm
-0
TRANSISTOR COMPLEMENT
SAFETY PROVISIONS
8 -2N527 General
3 -2N553 Delco
Grounded a -c power plug provided
Completely enclosed
117 a -c max voltage
Binding post for grounding chassis
Electric
-1N537 General Electric silicon diodes
-1N517 International zenner diode
2 -1N91 General Electric germanium diodes
2
1
ELECTRICAL SPECIFICATIONS
HOW TO ORDER
When ordering please specify Type BA -26 -A transistorized portable amplifier.
PERFORMANCE
Program circuits
MIX
1
FI
MIC I IN
O
MIC 2 IN
0-311
T2
LINE
CORD
13
MIC 3 IN
0-311
T4
MIC 4 IN
0-311
P. A
CUE LEVEL
FEED
DUAL
PHONE
JACKS
HI LEVEE
OUTPUT
INPUT
TERMINALS
t
Cu
OFF
LINE
KEY
ON
)1m
Control
AUDIO
Transistorized Audio Console
Page A105
Type BC -12 -A
Transistorized audio console, Type
FEATURES
Completely transistorized -not a tube in the circuitry
Use of transistors eliminates need for special cooling provision
Complete plug -in facilities for all amplifiers, and
relay modules -amplifiers may be quickly and
easily removed or replaced during service operations
Buy as you need; console can be operated with less
than full complement of preamplifiers; buy the
basic package, add more later as you expand
operations
Clean, "crackle- free" switch; springleaf, telephone type lever keys used
Noiseless fading and mixing -program controls are
high quality Doyen step -type attenuators
Improved operational efficiency with color -coded
controls; selector switches and associated lever key
handles are color coded for instant recognition and
prevention of operational error
Dual channel operation provided in console design;
addition of second program amplifier, second
master gain module, and VU meter, plus minor
terminal board changes, will permit simultaneous
two -channel operation. Second VU meter mounting
space is included in console for this purpose -no
interaction between two program channels when
so used
Built -in cue TB amplifier -console includes complete cue and talkback facilities with push- button
selector switch and speaker
BC -21 -A
Records, tapes and transcriptions easily cued. The
OFF position of hi -level attenuators equipped
cue switch to feed input to cue amplifier
with
WHERE TO USE
The General Electric Type BC -21 -A transistorized
audio console is designed for studio and or master
audio control of radio and television stations.
This console provides all the facilities required for
switching, mixing, and amplifying the outputs of
microphones, turntables, tape mechanisms, projectors,
remote and network lines, and other audio sources. It
also supplies facilities for auditioning, cuing, monitoring remote lines and cue talkback circuits to studio
and remote lines.
Completely transistorized, this all plug -in audio
console may be used for single -channel operation or
easily, quickly, and inexpensively modified for two channel operation.
DESCRIPTION
The Type BC -21 -A transistorized audio console consists of a desk unit containing four Type BA -21 -A preamplifiers, a Type BA -22 -A program amplifier, a Type
BA -24 -A monitor amplifier, and a Type BA -28 -A cue
talkback amplifier and associated mixer, gain control
and relay equipment. The Type BP -20 -A 25 -volt
power supply and the Type BP -21 -A 50 25 -volt power
supply are included in the basic package; but they are
rack mounted outside of the console.
The preamplifiers, high level mixer controls, and
master gain control are plug -in modules which make
up most of the lower front section of the console. These
Control
Transistorized Audio Console
Page A106
Type BC -21 -A
This console includes a master gain control module
and provisions for mounting the second channel
master gain control module. Space and connections are
provided for the installation of a second program
amplifier for dual channel operation.
By means of a 5- position monitor -selector switch, it
is possible to connect the monitoring amplifier input to
the program lines, the audition bus, or three external
lines.
Console open showing cue /talkback and program amplifiers
mounted in swing -up top and monitor amplifier in bottom of console at right. (Note: mounting space
for additional program amplifier in top
at right)
units are inserted from the front and become part of
the control pane' of the console. The cue talkback and
program amplifiers mount in the hinged top section of
the console; while the monitor amplifier and plug -in
relay modules are located in the console base.
This basic console handles up to eight low -level
microphone inputs which are selected by means of
microphone keys into the four preamplifiers. Up to ten
inputs can be handled by addition of another preamplifier module (accessory).
Eight high level program sources such as turntables,
tape and remotes or network are connected by means
of three eight -position spring leaf push- button switch
assemblies into three high level mixers.
T
T
T
T
T
T
3
2
;
R's
É
É
p
M
M
E
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2
Two output line key's are incorporated making it
possible to switch the program output to either of two
lines when the console is used as a single -channel unit.
In two channel applications, the line keys will connect
either output line to either channel. In single channel
operation, the keys control normal program output in
one position and in the other position provide emergency program output from the monitoring amplifier.
A single VU meter with associated selector switch
and pad is provided. By means of an extra meter hole
and dual overlay panel a second VU meter may be
mounted if desired.
This design incorporates a cue talkback amplifier
which with a push- button selector switch makes it
possible to communicate with either of two studios, an
announce booth, or NEMO lines without affecting
monitor facilities. A 4 -inch speaker is mounted on the
console and serves as both TB mike and cue speaker.
An eight -position push- button switch assembly provides for selection of six intercommunication positions,
a cue position and a LISTEN TALK operate button.
The LISTEN TALK button is red versus black for
other positions.
r
ú
o
Cue talkback selector and gain control panel
2
4
1
HI
s
Ö
IEVEI SEIlî.TOR
I
PHONES
1
High level input selector panel
All audio sources feed into mixer bus keys which
provide the means of selecting either the program bus
or the audition bus. In the case of two -channel operation, the audition bus becomes program bus number
two.
For cue purposes, the talkback amplifier doubles as
the cue amplifier. Cue faders are used in the three
high -level mixer positions. The cue output of these
faders is connected to a common bus brought up to a
position on the cue talkback selector switch.
This console design includes speaker and warning
light cut -off relays and associated circuitry. Provisions
are made for operation of both audition and on -air
warning lights. Relay control circuits provide for
operation of two studios, an announce booth, and the
control room speaker. Four printed wire board relay
assemblies are supplied. These relay modules plug into
the console proper.
This console provides a pair of phone jacks for
monitoring each channel via a headset.
A spare key is provided (mounted adjacent to the two
line keys) which may be wired by the customer for such
purposes as feeding recorders, studio amplifiers, etc.
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Control
AUDIO
Transistorized Audio Console
Type
MIC
I
Page A107
BC -12 -A
A
IB
MIC
MIC
2A
MIC
MIC
2B
3A
MIC
MIC
38
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PGM 2
PGM
°LINE
PMON
I
PGM
AMP
°LINE 2
4A
MIC 4B
ANNC MIC
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PGM2 r+
MIC
MON
T. T.
GEM
I
T. T. 2
T. T.
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'RELAY L.-.
ANNC.
rI
NET/NEMOj2
3
RELAY`
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RELAY
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P.B.
SPKR
AIR
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SPKR
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2
-°
--°
AMP
3
TAPE
PROJ
TAPE
PROJ
TO C.R.
-MON SPKR
P.B.
SWI SW.2 SW.3
CUE
&TB
SPKR -MI
McNai Menazr¢Naa aMMCST
J
STUB
"-T.B. SELECT-
LIGHIT
DC CONTROL
CIRCUITS
NOT SHOWN
NOTE:FOR DUAL CHANNEL OPERATION REMOVE
STRAP BETWEEN X -Y AND CONNECT
Y TO Z.
Line diagram of transistorized audio console, Type BC21A. Note how easily it can be
T.B. /CUE AMP
modified for dual channel operation
An OVER -RIDE switch is included in the console
design. This OFF,- ON switch connects the three
remote lines to the monitor speaker input. The only
exception being that if a remote line is being fed
program material for cue purposes that line is automatically disconnected from the over -ride bus.
A four -position switch makes it possible to selec
tively feed program material for remote cue purposes
to any one of three remote lines. When a remote line
is being fed cue, it is removed from the over -ride circuit.
A single VU meter is mounted in the console together with a four -position meter selector switch
which provides the following selections:
(a) OFF
(b) CHAN 1 (Connects meter to Chan 1 output
line.)
(c) CHAN 2 (Connects meter to the monitor output. In a two -channel conversion, this
position is reconnected to the No. 2
output line.)
(This position connects the meter to a
(d) EXT
pair of terminals which may be used to
meter some external audio circuit.)
Circuits associated with the monitor amplifier include a gain control and an input- selector switch. Both
these controls are mounted on the upper right -handside of the console. The selector switch makes it possible to switch several lines to the monitor input. The
positions in detail are:
(a) OFF
(b) CHAN 1 (Bridges monitor input to program
channel No. 1 output.)
(c) CHAN 2 (Connects Chan 2 (audition) mixer bus
to the monitor input. In a two -channel
conversion this position is reconnected
so that it bridges Chan 2 program
output).
(d) EXT
(e) EXT
Bridges monitor input to three sets of
terminals for connection to three remote audio circuits.
1
2
(f) EXT
3
MECHANICAL SPECIFICATIONS
UNITS
Type number covers the console assembly, four Type BA -21 -A
preamplifier modules, a Type BA -22 -A program amplifier, a
Type BA -24 -A monitor amplifier, a Type BA -28 -A cue talkback
amplifier, a Type BP -20 -A 25 -volt power supply, a Type BP21-A 50/25 -volt power supply, and associated equipment.
DIMENSIONS
(Exterior console dimensions)
Length
Height
Depth
17
inches
11
Weight
38 inches
inches
75 lb
MOUNTING
All amplifier chassis are plug in and mount in console. The console
cabinet may be mounted on two Type PR- 16 -B /C base cabinets
or any available desk of sufficient size. The power supplies mount
f
Off
/
ON
/
ITT
//4
LINE-
I
CM-I
MONITOR
siiisl
I
CM
DFf.
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4.1'
ert
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7
Monitor, VU meter and line output control panel
Control
Page A108
Transistorized Audio Console
Type BC -12 -A
High level plug -in module
in one of the base cabinets or any standard EIA cabinet rack,
such as the Type PR -1 -A cabinet rack (accessory ).
CONTROLS AND ADJUSTMENTS
5-Microphone selector keys
4 -Mixer and mixer keys (part of preamplifier module)
3- Eight -position push- button selector switches for high
level
sources
3
-High
level mixers and mixer keys
1- Master gain control
-Monitor selector switch
-Monitor gain control
1
1
-VU meter
21-
3
-Line isolation transformers
PERFORMANCE
Program Circuits
Frequency Response:
2 db, 50 to 15,000 cps
Gain: 105 db 2 db
Noise: 65 db below +18 dbm out (with controls set for 68
db of gain)
Crosstalk (Nominal i:
At least 50 db down, 50- 15,000 cps
At least 80 db down, at 1000 cps
Distortion: 1 percent or less at +18 dbm (after 6 db pad)
Monitor Circuits
selector switch
Output keys
Eight -position push- button cue talkback selector switch
1-Over -ride switch
1 - Cue TB gain control
1 -Spare key (utility)
1-- Remote PGM cue selector switch
1
ELECTRICAL SPECIFICATIONS
Frequency Response:
1 db, 50 to 15,000 cycles
Distortion: 1 ., percent or less at +33 dbm
1
POWER REQUIREMENTS
110 117,125 volts, 50 60- cycle, single -phase, a -c, 90 watts
(45 watts each power supply)
25 volts, d -c at 1 -amp for the monitor amplifier and control
relays, from the Type BP -20 -A power supply.
50 volts, d -c at 500 ma for program amplifier and cue talkback
Master gain control module
Control
AUDIO
Transistorized Audio Console
Type
BC -12 -A
amplifier as well as 25 volts, d -c at 40 ma for the preamplifiers
from the Type BP -21 -A power supply.
SIGNAL INPUTS
Impedances
Microphones: 10- 30/150'250/600 ohms, balanced or unbalanced
Turntables: 3 -600 ohms, balanced or unbalanced
Network or Remote Lines: 3 -- 600, 150 ohms, balanced or
unbalanced
Tape/Projectors: 2 -600 ohms, balanced or unbalanced
External Monitors: 3 - -- 20,000 ohms, balanced, bridging
External VU: 1 -7500 ohms, balanced, bridging
Levels
Low Level Inputs- Microphone level to --25 dbm
High Level Inputs- - -10 to +18 dbm
SIGNAL OUTPUTS
HOW TO ORDER
When ordering please specify Type BC -21 -A transistorized audio console which includes:
Console cabinet
4 -Type BA -21 -A preamplifier modules
1 -Type BA -22 -A program amplifier
1 -Type BA -24 -A monitor amplifier
1 -Type BA -28 -A cue talkback amplifier
1 -Type BP -20 -A 25 -volt power supply
1 -Type BP -21 -A 50 25 -volt power supply
1-
ACCESSORIES
Type BA -22 -A program amplifier for two -channel
operations
Type BA -21 -A preamplifier module for fifth position on console
Type BA -24 -A monitor amplifier for auxiliary
speaker operation
Type BP -20 -A 25 -volt power supply for extra monitor amplifiers (one BP-20 -A will provide adequate
power for two monitor amplifiers)
or
Dual channel kit 7168290 consisting of:
1 -Type BA -22 -A program amplifier for two-.
channel operation
1- 7164636 master gain module
1- 7477541 -4 meter attenuator
1- 7492839 -1 VU meter
Impedances
Program Lines (Regular): 2 600 ohms, balanced
Monitor Channel: 1- -600 150 8 ohms, balanced
Remote Cue (into NEMO line): 3 Bridging, balanced
Levels
Program output level -+18 dbm
Monitor output level - - +33 dbm (2 watts)
TRANSISTOR COMPLEMENT
1
1
2N277 Delco
-2N173 Delco
1- 2N169A General
Electric
3 -2N441 Delco
25 -2N324 General
6 -1N538 General
10-- -2N320 General
2
2 --
Page A109
Electric
Electric Silicon Diode
Electric
CTP 1133 Clevite
2N553 Delco
Transistorized audio console, Type
BC -21
-A, for dual channel operation
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AUDIO
Control
Bridging Volume Control
Page
A
1 1
1
Type FA -35 -G
General Electric bridging volume control, Type FA -35 -G
WHERE TO USE
MECHANICAL SPECIFICATIONS
The General Electric Type FA -35 -G bridging volume control is designed to convert a 600 -ohm input of
an amplifier to 10,000 ohms balanced bridging service.
It may be used on line levels up to +40 dbm.
DIMENSIONS
Height
Diameter
2!9 inches
1
¿inches
Weight
2
ounces
MOUNTING
The Type FA -35 -G is designed to fit holes provided in the
ends of the Type BA -1 -F pre -amplifier and the Type BA-12 -C
program /monitor amplifier chassis. It may also be mounted on
the Type BA -4 -E monitoring amplifier or used in similar applications where a bridging gain control is required. A % -inch hole is
required for mounting in applications other than outlined above.
(See outline diagram for internal chassis clearance dimensions.)
DESCRIPTION
The General Electric Type FA -35 -G consists essentially of a continuously variable dual potentiometer, a
screwdriver control (a knob may be used), and a
dummy switch section tandem - mounted to provide
terminals for mounting two resistors and input connections to the control.
HOW TO ORDER
When ordering, please specify:
Type FA -35 -G bridging volume control.
10K
OHMS
4
Outline and elementary diagrams, Type FA -35 -G bridging volume control
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Power
Supplies
AUDIO
Plug -in Power Supply
Page A201
Type BP -10-B
Plug -in power supply, Type BP -10 -B
MECHANICAL SPECIFICATIONS
FEATURES
Compact, plug -in construction
DIMENSIONS
Easy to remove, maintain and service
Conservatively rated components
Screwdriver control to adjust
value
B
Depth
Height
93"i
51 ¿
inches
inches
Width
7% inches
Weight 25 lb (approx)
MOUNTING
voltage to current
The BP -10 -B plugs into a Type FA -23 -B shelf.
OPERATING CONDITIONS
May be operated in an external ambient of up to 113 F (45 C)
and a relative humidity up to 95 percent.
WHERE TO USE
The General Electric Type BP -10 -B plug -in power
supply is specifically designed to power plug -in audio
amplifiers Types BA -1 -F, BA -9 -A and BA -12 -C. It
will also supply TV or other equipment which will operate from an unregulated supply of Type BP -10 -B
ratings.
DESCRIPTION
The Type BP -10 -B is a plug -in unregulated power
supply, constructed on a narrow recessed chassis with
all controls and components marked. Fuses and
operating controls are accessible from the front. A
Jones plug that mates with a corresponding receptacle
on the Type FA -22 -F tray makes all necessary electrical contacts.
A voltage divider across the d -c output serves as a
bleeder and as a source of low voltage d -c for biasing
the filament supply 30 volts positive to minimize hum
output from amplifiers.
One Type BP -10 -B can supply power for up to 25
Type BA -1 -F pre -amplifiers, or three Type BA -9 -A
uni -level amplifiers, or three Type BA -12 -C program
monitor amplifiers at 300 volts B +.
SAFETY PROVISIONS
Wiring and terminals are enclosed in a grounded chassis. No
exposed voltages because of plug -in construction.
ELECTRICAL SPECIFICATIONS
TYPE OF CIRCUIT
Full -wave, single -phase rectifier using two 5Y3 tubes in
parallel. Use of parallel rectifiers increases power supply reliability under average load conditions. The filter is a pi -filter
with a rheostat located in the B +circuit just ahead of the output
capacitor. Filament supply is maintained at +30 -volt bias.
PERFORMANCE
Potentiometer adjustment to +300 -volt for all loads from 40
ma to 230 ma. Maximum ripple, full load: 25 my (120 cycles).
INPUTS
110/117/125 -volt, 50 /60- cycle, 200 -watt single -phase.
OUTPUTS
40 to 230 ma adjustable to 300 -volt d -c at nominal input
transformer tap voltages; 4.5 -amp at 6.4 -volt a -c at 50- cycle,
7.5 -amp at 6.4 -volt a -c at 60- cycle; at 50 cycles this unit will
supply three Type BA -12 -C amplifiers or 15 Type BA -1 -F amplifiers; at 60 cycles this unit will supply three Type BA -12 -C
amplifiers or 25 Type BA -1 -F amplifiers.
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Power
Supplies
Page A202
Plug -in Power Supply
INTERNAL POWER SUPPLIES
The Type BP -10 -B also derives and establishes the filament
winding at a positive bias of 30 volts.
CONTROLS AND ADJUSTMENTS
Voltage output can be adjusted to 300 -volt d -c, by a screwdriver adjustment located above the chassis, under all load
conditions from 40 to 230 ma. Fuses are removable from the
front of the chassis.
TUBE COMPLEMENT
2
Type 5Y3GT,'G
Type BP -10 -B
HOW TO ORDER
When ordering, please specify:
Type BP -10 -B plug -in power supply.
ACCESSORIES
Type FA -23 -A shelf, for mounting plug -in units
with trays. (Type FA -23 -A occupies seven inches
four units of rack height in a Type PR -1 -A cabinet
rack and will accommodate six pre -amps, Type BA1-F, four Type BA -12 -C program monitoring amplifiers, or two Type BP -10 -B power supplies.)
Plug -in power supply, Type BP -10 -B, plus plug -in program /monitoring amplifier, Type BA -12 -C; and plug -in preamplifier, Type BA -1 -F, mounted in broadcast shelf, Type FA -23 -A. (Front view, right, with shelf panel open.)
AUDIO
Power
Supplies
Transistor Power Supply (25 -volt)
Page A203
Type BP -20 -A (Regulated)
Transistor power supply (regulated), Type BP -20 -A 25 -volt
FEATURES
MOUNTING
Standard rack mounting
All transistor-no tubes in circuitry
Maintains constant regulated output voltage
Full -wave rectification
Fuses fully protect supply from overload
Regulation adjustable for various line voltage conditions
Voltage- adjust control and test jacks on front of
panel
Fuse posts on
front of panel
OPERATING CONDITIONS
Maximum room ambient temperature, continuous 113 F
(45 C), 5 percent of the time 122 F (50 C).
Maximum cabinet ambient temperature -- continuous 122 F
(50 C), 5 percent of time, 113 F (55 C).
ELECTRICAL CONNECTIONS
A -c input and d -c
minal boards
output connections made on separate ter-
SAFETY PROVISIONS
Primary and secondary circuits are fused. Maximum voltage
and 25 -volt d -c.
117 -volt a -c
WHERE TO USE
The General Electric Type BP -20 -A 25 -volt transistor power supply provides the regulated 25 -volt d -c
required for operation of the Type BA -24 -A transistor
monitor amplifier and control relays as used in the
Type BC -21 -A transistor audio console. In alternate
applications, it can supply adequate power for two
and in some cases three monitor amplifiers.
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Output voltage changes less than 1 percent with load changes
from no load to one ampere and input voltage changes of } 10
volts. Less than one millivolt ripple with full load.
INPUT POWER REQUIREMENTS
110/117/125 volts a -c, 50-60- cycle, 45 watts
POWER OUTPUT
DESCRIPTION
25
The Type BP -20 -A 25 -volt transistor power supply
employs silicon -rectifier cells in a full -wave center
tapped circuit. The regulation is obtained by a transistorized series regulator circuit consisting of three
transistors and a zener diode.
volts regulated d -c,
1
ampere
CONTROLS AND ADJUSTMENTS
ON -OFF switch
Voltage control potentiometer
TRANSISTOR COMPLEMENT
1
1
-2N277 (Delco)
-2N441 (Delco)
1
-2N324 (General Electric)
MECHANICAL SPECIFICATIONS
DIMENSIONS (Two rack units)
Depth
Height
6X inches
3% inches
Width
Weight
19 inches
5
lb,
11
oz
HOW TO ORDER
When ordering please specify Type BP-20 -A 25volt transistor power supply.
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Power
Supplies
AUDIO
Transistor Power Supply (50/25-volt)
Type
BP -21 -A
Page A205
(Regulated)
Transistor power supply (regulated), Type BP -21 -A 50 /25 -volt
OPERATING CONDITIONS
FEATURES
All transistor -no tubes in the circuitry
Maintains constant regulated output voltage
Full -wave rectification
Fuses fully protect supply from overload
Regulation adjustable for various line voltage conditions
Voltage- adjust control and test jacks on front panel
Maximum room ambient temperature, continuous 113 F
(45 C), 5 percent of the time 122 F (50 Cl
Maximum cabinet ambient temperature- continuous 122 F
5 percent of time, 131 F (55 C)
(50 C),
ELECTRICAL CONNECTIONS
A -c input and d -c
minal boards
output connections made on separate ter -
SAFETY PROVISIONS
Primary and secondary circuits are fused. Maximum voltage
and 50 -volt d -c.
117 -volt a -c
WHERE TO USE
The General Electric Type BP -21 -A 50 25 -volt
transistor power supply provides the regulated 50 -volt
d -c for operation of up to two Type BA -22 -A transistor
program amplifiers and a Type BA -28 -A transistor
cue talkback amplifier. It also furnishes the regulated 25 -volt d -c required by up to five Type BA -21 -A
transistor preamplifiers.
In alternate applications, a single power supply will
supply up to four program and or cue amplifiers.
DESCRIPTION
MECHANICAL SPECIFICATIONS
DIMENSIONS (Two rack units)
6% inches
3 ' , inches
PERFORMANCE
Output voltage changes less than 1 percent with load changes
from no load to 560 ma or with input voltage changes of *10
volts. Less than 750 microvolts ripple with full load.
INPUT POWER REQUIREMENTS
110 117 125 -volt d -c, 50 -60- cycle, 45
watts.
POWER OUTPUT
50
25
volts (regulated) d -c, 560 ma
volts (regulated) d -c, 40 ma
CONTROLS AND ADJUSTMENTS
The Type BP -21 -A 50 25 -volt transistor power
supply employs silicon- rectifier cells in a full -wave
bridged circuit. The regulation is obtained by a transistorized series regulator circuit which employs four
transistors and a zener diode. An additional circuit
using a choke coil, capacitor, and an adjustable resistor
supplies the 25 -volt d -c required for the preamplifiers.
Depth
Height
ELECTRICAL SPECIFICATIONS
Width
Weight
19
5
inches
lb, 11 oz
ON -OFF switch, voltage adjust
CONTROL POTENTIOMETER
A slide -wire resistor mounted on the chassis makes it possible
to adjust the 25 -volt output for 32 to 40 ma loads.
TRANSISTOR COMPLEMENT
1
2
2N173 (Delco
2N441 (Delco
1
4
2N324 (General Electric)
-1N538 (General Electric)
HOW TO ORDER
When ordering please specify Type BP -21 -A 50 25volt transistor power supply.
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AUDIO
Broadcast Shelves
Types FA -23 -B, FA -23 -C, and FA -46 -A
Shelves
and
Cabinetry
Page A301
Front view of Type FA-23-8 shelf
FEATURES
Easy to service and maintain
Hinged front panels permit easy, quick replacement of
amplifiers, or power supplies.
Space saving
Construction of shelf, occupying only seven inches of
vertical rack space, permits many amplifier combinations to be compactly mounted in a small area.
Improved rack appearance
Door, when closed, covers all shelf mounting hardware.
Shelf panel matches other
mounted audio panels.
General
Electric
rack -
Easy amplifier replacement
Extractor tool, clipped to inside of front panel, permits
rapid and easy withdrawal of amplifiers for maintenance or service.
Type FA -23 -C panel adapted
for mounting of con-
trols and indicating light jewels
Type FA -23 -C shelf is equipped with shaft extensions for
Type BA -14 -A controls. Front panel is equipped with
two control scales and plug buttons for both the controls
and indicator light jewels.
Mounts many amplifier combinations
Spacer bars and mating receptacles may be mounted
in any desired manner to permit use of different types
of General Electric audio amplifiers. Shelf base is drilled
to mount spacer bars and receptacles.
Type FA -23 -B
The General Electric Type FA -23 -B broadcast shelf
designed to mount in a standard EIA 19 -inch cabinet or relay rack. This shelf, occupying only seven
inches of vertical rack space, provides mounting space
is
for General Electric plug -in audio amplifiers in any of
the following combinations:
Six Type BA -1 -F pre- amplifiers, or
Four Type BA -9 -A uni -level amplifiers, or
Four Type BA -12 -C program monitor amplifiers, or
Two Type BA -3 -A equalized transcription pre-
amplifiers, or
Two Type BP -10 -B power supplies.
Combinations of the various units are possible such
as mounting three Type BA -1 -F pre -amplifiers and
two Type BA -12 -C program monitor amplifiers or
two Type BA -9 -A uni -level amplifiers on a single
Type FA -23 -B shelf.
The plug -in audio equipment may be easily inserted
in or withdrawn from the mating receptacles mounted
on the shelf. An extractor tool, clipped to the shelf
door, aids in quick removal of amplifiers through the
front of the rack.
Type FA -46 -A
The General Electric Type FA -46 -A broadcast shelf
identical to the unit just described less the front
panel and hinges.
is
Type FA -23 -C
The General Electric Type FA -23 -C broadcast shelf
designed to permit rack mounting of the General
Electric Type BA -14 -A program monitor amplifiers.
This shelf, similar in appearance, size, and function to
the Type FA -23 -B broadcast shelf, differs in that the
front panel of the Type FA -23 -C shelf contains four
holes with plug buttons, control decals for the operating controls, andthe indicating light jewels of the Type
is
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Shelves
and
Broadcast Shelves
Cabinetry
Types FA -23 -B, FA -23 -C, and FA -46 -A
Page A302
BA -14 -A program monitor amplifier. If a front panel
volume control is not required, the Type BA -14 -A can
be mounted in a Type FA -23 -B shelf. Both shelves are
furnished with the same number of mating Jones
mounted on the inside of the front panel of the Type
FA -23 -B and Type FA -23 -C holds the extractor tool
for ready use whenever it becomes necessary to remove
or insert an amplifier or power supply.
receptacles and spacer bars.
DESCRIPTION
The General Electric Type FA -23 -B, FA -23 -C and
FA -46 -A broadcast shelves are designed to mount the
General Electric line of plug -in audio amplifiers and
power supplies in standard 19 -inch EIA cabinet or
relay racks. Through the use of these shelves, from
two to six amplifiers or power supplies (depending
upon the type) may be mounted in only seven inches
of rack space.
Front view of Type FA -23 -B shelf, with front panel open
All steel parts are given a rust -proof plating of
cadmium.
The front panel of the Type FA -23 -B shelf is
painted a dark metalustre blue and is devoid of holes
or control designations.
Rear
view of Type FA -23 -B shelf, showing mounted Type BA -1 -F and
Type BA -12 -C amplifiers
These shelves are identical in construction, size, and
appearance except for the addition of four holes (with
plug buttons furnished) and two scales on the front
panel of the Type FA -23 -C shelf and the lack of front
panel and hinges on the Type FA -46 -A.
Front view of Type FA -23 -C shelf, showing front panel control
of mounted Type BA -14 -A amplifiers
The front panel of the Type FA -23 -C shelf is painted
a dark metalustre blue, and is provided with four holes
Front view of Type FA -46 -A shelf
All models are equipped with five spacer bars, six
receptacles, and special
brackets. The bases of the shelves are drilled to permit
mounting the spacer bars and receptacles in different
configurations. Both the spacer bars and receptacle
brackets are drilled and tapped for this purpose.
Essentially the shelves consist of a drilled, horizontal plate, two mounting flanges, and a spring
loaded, hinged front panel. The mounting flanges, an
integral part of the horizontal base, are folded up
vertically and are notched with standard EIA slots for
rack mounting in a 19 -inch cabinet or rack. A clip,
10 -pin Cinch -Jones 2400 series
and two calibrated scales. These holes and scales are
used for mounting the two indicator light jewels and
for passage of the extension shafts of volume controls
in the Type BA -14 -A program 'monitor amplifiers.
The knobs furnished are the push-on type permitting
ready insertion or removal of the knobs whenever it
becomes necessary to open the front panel.
A shelf utilizes fourteen inches of space between the
rear of the front mounting surface and the rear of the
shelf. When these shelves are mounted in a General
Electric Type PR -1 -A cabinet rack, the No. 12 -24
mounting screws (furnished) are hidden from sight by
the exclusive General Electric rolled front panel and
cabinet design, an important contribution to the neat
appearance of your control or equipment room.
www.americanradiohistory.com
Shelves
and
AUDIO
Broadcast Shelves
Cabinetry
Types FA -23 -B, FA -23 -C, and FA -46 -A
Page A303
MECHANICAL SPECIFICATIONS
UNITS
Type FA -23 -B
1
FA -23 -B shelf
5- Drilled and tapped spacer bars, with screws
6- Cinch -Jones S -2410 10 -pin female connectors
shelf mounting brackets
1- Extractor tool
Mounting screws
with special
Type FA -46 -A2
As above less extractor tool, front panel and hinges
Typo FA -23 -C
1
-Shelf with panel plug buttons and two calibrated scales
2-Extension shafts
2- Control knobs and springs
5- Drilled and tapped spacer bars, with screws
6- Cinch -Jones S -2410 10 -pin female connectors
shelf mounting brackets
with special
-- Extractor tool
Mounting screws
1
DIMENSIONS (Four rack units)
Depth
Height
13
¿
inches
6:Z inches
Width
Weight
19
inches
9 lb
MOUNTING
Type FA -23 -B, FA -23 -C and FA -46 -A shelves bolt to the front
of the cabinet or relay rack with No. 12 -14 round head screws
(furnished). They may be mounted in any standard 19 -inch
width cabinet or relay rack with at least 14 -inch clearance between the front panel and the rear door.
FINISH
Front panel -- General Electric dark metalustre blue
Shelf base and hardware- cadmium plated for rust prevention
Rear view of Typo FA -23 -C shelf, showing mounted
Type BA -14 -A amplifiers
HOW TO ORDER
When ordering please specify:
General Electric Type FA -23 -B broadcast
shelf. (Type number includes shelf, panel, spacers,
connectors and brackets, extractor tool, mounting
screws, and installation instructions.)
Or
General Electric Type FA -23 -C broadcast
shelf. (Type number includes shelf, panel with scale
and plug buttons, spacers, connectors and brackets,
extractor tool, extension shafts, push -on knobs, and
installation instructions.)
or
General Electric Type FA -46 -A broadcast
shelf. (Type number includes shelf, spacers, connectors
and brackets, mounting screws, and installation instructions.)
www.americanradiohistory.com
AUDIO
Shelves
and
Broadcast Shelf
Type FA -48 -A
Cabinetry
Page A305
1
Broadcast shelf, Typs FA -48 -A1
in a standard 19 -inch cabinet or rack. The hinged
FEATURES
Fits any standard rack. The Type FA -48 -Al broadcast shelf is designed to fit 19 -inch EIA cabinet rack.
Easy to maintain and service. Hinged front panels
permit easy, quick replacement of amplifiers
Space saving. Shelf occupies only
space
51/4
inches of rack
front panel covers the front of the shelf and conceals
the mounting screws. The shelf must have at least
131 inches clear depth between the front mounting
surface and the rear door of a rack cabinet.
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth 13;6 inches
Height 5% inches
WHERE TO USE
The General Electric Type FA-47-Al broadcast
shelf is designed for mounting the General Electric
line of plug -in, transistorized audio amplifiers. This
shelf occupies five and one quarter inches of vertical rack space and is equipped to accommodate four of the
following plug -in amplifier types:
Type BA -22 -A program amplifier
Type BA -24 -A monitor amplifier
Type BA -28 -A cue /talkback amplifier
Width
Weight
19 inches
6 Ib
MOUNTING
The Type FA -48 -Al shelf bolts to the front of the cabinet or
rack with No. 12-24 mounting screws (furnished). They may be
mounted in any 19- inch -wide cabinet or rack with at least 131
inch clearance between the front panel and the rear door.
FINISH
Front panel -General Electric dark metalustre blue outside
and inside. Chassis-cadmium plated.
HOW TO ORDER
DESCRIPTION
The General Electric Type FA-48-Al broadcast
shelf is designed to mount the General Electric line of
plug -in amplifiers. This shelf consists of a horizontal
plate equipped with two vertical end -mounting brackets, a hinged -front panel, four plug -in connectors, four
fuse -holders with indicator lights, and four adhesive
backed write -in strips. The end brackets are provided
with mounting slots and screws for fastening the shelf
When ordering please specify General Electric
Type FA-48-Al broadcast shelf.
:
ACCESSORIES
Type BA -22 -A1 program amplifier
Type BA-24-Al monitor amplifier
Type BA -28 -A1 cue,'talkback amplifier
www.americanradiohistory.com
Shelves
and
Cabinetry
Page A306
Broadcast Shelf
Type FA-48-Al
Broadcast shelf, Type FA -48 -A1 (open panel view)
Broadcast shelf, Type FA -48 -A1 (rear view)
www.americanradiohistory.com
AUDIO
Shelves
and
Cabinet Rack
Type
PR -1
Cabinetry
-A and Accessory Items
Page A307
FEATURES
Versatile
Adaptable for mounting either broadcast audio, or
television chassis and panels, removable front and rear
doors are arranged for left or right opening. Chassis
and panels may be mounted in a number of various
positions from the front (in which case the front door is
not used) to the rear of the cabinet on the movable
equipment mounting angles spaced for 19 -inch rack -
BLOWER KIT
CAT. No. 7485321 -G2
EQUIPMENT MTG.
ANGLE IN CENTER
POSITION
WIRING DUCT
mounted equipment.
Ease of wiring
Harnesses are eliminated by use of Type PR -5 -A wiring
ducts which have removable covers providing maximum
accessibility to accessory wiring.
TYPE PR -5 -A
LFRONT DOOR
TYPE PR -3 -A
Accessibility
LATCH CAM
(CAN BE HINGED
FROM EITHER SIDE)
Emphasized by convenient locations for terminal boards
and wiring cables and absence of awkward trim strips.
Sturdy
Welded skin construction with welded stiffeners
front door.
TERMINAL BOARD
FRAME MOUNTING
ANGLE
in the
Attractive
AIR FILTER ON DOOR
(PART OF BLOWER KIT)
Panel edges are concealed by recessed front mounting
surface.
Excellent ventilation
Natural draft characteristics
in
TERMINAL BOARD
FRAME TYPE PR -4 -A
addition to provision for
connection to a pressurized system.
Safe
High -voltage door -interlock switch kits (Cat. No.
7460330 -G4) are available to attach to the Type
PR -1 -A cabinet rack so that high voltages are grounded
when either the front or rear doors are opened.
WHERE TO USE
The General Electric Type PR -1 -A cabinet rack
provides space for mounting any broadcast or television audio and video chassis and panels designed for
installation in a standard 19 -inch rack.
DESCRIPTION
The Type PR -1 -A cabinet rack consists of a rigid
welded -sheet steel cabinet with an open front and a
hinged -rear door. Two equipment mounting angles
and two short terminal board frame mounting angles,
each containing No. 12 24 tapped holes located in
accordance with EIA standards, are provided with
each rack. The front door is available as an accessory.
The outstanding feature of the Type PR -1 -A is its
versatility. Any combination of General Electric audio
and video chassis plus other manufacturers' standard
rack equipment can all be mounted in the same rack.
This is possible because of the three locations for the
equipment mounting angles within the rack. Front,
intermediate, and rear mounting positions are provided. A neat and uniform appearance can be maintained even when units of different types are installed.
The front position of the mounting angle is for
panel- mounted equipment that will be approximately
flush with the front edge of the rack, without a front
door, as in conventional audio practice. This position
is
-inch behind the front surface of the cabinet shell
so as to recess the audio panels slightly within the
front surface of the cabinet and thus conceal the panel
edges.
I
AUDIO TERMINAL BLOCK
CAT. NO. 7118764 -G1
POWER TERMINAL BOARD
CAT. NO. 7118765 -G1
Cabinet rack, Type
PR -1
-A, and accessory items
The intermediate position is 4;;, inches behind the
front surface of the cabinet shell and is intended for
any standard panel- mounted units such as jack -panels,
audio amplifiers, standard test equipment, and some
front -mounted television units when a front door is
used. With this type of mounting, the front door is
used to screen an otherwise heterogeneous appearance
and to provide a closed rack so that pressurized
ventilation, if used, will be more effective.
The rear position is ideal for mounting television
power supplies, video amplifiers, and other chassis type television units with or without the use of a front
door. The mounting surface of the angle in this position is located 11 inches behind the front surface of
the cabinet shell. Combinations of front, intermediate,
and rear positions may also be used in the cabinet.
The rear door is hinged on the right -hand side when
the rack is shipped. As with the front door, the hinges
may be reversed and the door swung from the left hand side if desired.
Ventilation openings provided in the cabinet rack
consist of two perforated grilles in the rear door, a
large cut -out in the cabinet top, and cabinet base. A
horizontal rectangular dust plate about one inch below the top cut -out protects equipment in the cabinet
from dust and other foreign matter. This plate may be
removed if an air duct or fan is attached to the cabinet
top for forced ventilation.
Three horizontal mounting channels on each side of
I
Shelves
and
Cabinet Rack
Cabinetry
Type
Page A308
PR -1 -A
the cabinet interior with nine tapped holes in each
channel are used for mounting the vertical equipment
mounting angles in any of three locations and for
mounting such cabinet accessory items as wiring
ducts, cabling straps.
SPECIFICATIONS
TYPE PR -1A CABINET RACK
Consists of a cabinet shell and ventilated rear door, a pair of
equipment mounting angles, a pair of terminal -board frame
mounting angles, a set of mounting hardware, and two instruction books.
DIMENSIONS
Total height
Vertical mounting space
Total width
Total depth
WEIGHT
83%8 inches
77 inches (44
22 inches
near the bottom of each cabinet to provide mounting
facilities for the required terminal boards.
Type PR -5 -A, Wiring Duct
Weighing 12 lb, the wiring duct is a metal channel
with 42 slots fitted with rubber grommets. It is
recommended that two wiring ducts, Type PR -5 -A,
be mounted in each cabinet rack; one on the right hand side (facing rear of cabinet) for audio or video
inter -unit wiring, and one on the left -hand side for
power, metering, and control inter -unit wiring.
Type PR -7-A, Mounting Angles
The mounting angles consist of a pair weighing 14
lb and of the following dimensions: 1 , inches by
., inches by 80N inches long. Each is of zinc -plated
1
steel and includes angle mounting hardware. These
angles are for use when it is desirable to mount panels
or chassis on two mounting locations at the same
time, such as mounting "bathtub" chassis with General Electric equipment in the Type PR -1 -A rack.
I
rack units
)
2331 inches
130
and Accessory Items
lbs
MOUNTING
The Type PR -1 -A cabinet rack is floor mounted. Mounting
space 77 inches high (44 rack units 1, 19 inches wide, and 21
inches deep is available for mounting chassis and panels.
OPERATING CONDITIONS
It is condidered good practice to limit the cabinet air temperature rise to 10 C or 15 C over the room ambient temperature for
most applications. Natural (non- forced ventilation will dissipate
about 350 watts of heat for a 10 C rise in cabinet air temperature
and about 525 watts for a 15 C rise.
)
ACCESSORIES (Description)
Type PR -2 -A, Hinged Panel Assembly
This assembly serves as a front cover and access
panel for various television units which mount on
equipment mounting angles fastened in the intermediate or rear (center -of -rack) positions of a Type PR1 -A cabinet rack when a front door can not be used
with the rack. When a monitor is mounted, with a
Type PR -19 -C monitor cabinet rack adapter kit, in a
cabinet rack, a Type PR -3 -A front door can not be
used because the front panel of the monitor must be
visible. If power supplies, utility video amplifier
groups, etc., are "center of rack" mounted in the same
cabinet rack, Type PR -2 -A hinged panel assembly
is available to close up the front of the cabinet rack
flush with the front panel of the monitor. This arrangement has the same effect as a front door so that
any normal method of air -cooling the equipment in the
cabinet rack can be employed. Since the panel is
hinged, the units mounted behind it are quite accessible.
Type PR -3 -A, Front Door
Similar to rear door except for the omission of perforated grilles. Weight is approximately 40 lb. It may
be mounted for either right- or left -hand opening.
Type PR -4 -A, Terminal Board Frame
Weight is 3 lb. The terminal board frame provides
mounting holes to accommodate three audio terminal
blocks, ML- 7118764 -G1, and three power terminal
boards, ML- 7118765 -GI. By relocating the two middle
straps, the frame will mount six power- terminal
boards and one audio -terminal block. It is recommended that one terminal -board frame be installed
I
Type
PR -8 -A,
Cabling Straps
The cabling straps consist of a pair of steel straps
1.,-inch wide by ! s -inch thick by 73 inches long, in
addition to hardware for mounting in the cabinet
rack. These straps mount vertically in the rear of the
cabinet in place of the wiring duct, and serve as an
inexpensive means for supporting cabinet inter -unit
wiring.
Type
PR -9 -A,
Mounting Frame
Ten inches (six rack units) to mount video and sync
amplifier groups.
Type PR -9-E, Mounting Frame
Eight and three quarter inches (five rack units)
to mount TS -2 -A switching components.
Type
PR -9 -F,
Mounting Frame
Fifteen and three quarter inches (nine rack units)
to mount TS -2 -A switching components.
Type PR -19 -D, Adapter Kit
The adapter kit is 21 inches (twelve rack units)
and is used to mount Type TM -21 -A monitor.
Cat. No. 7118764 -G1 Audio Terminal Block
Weighing one lb, this unit is an 80- terminal (four
rows of 20 each) solder -lug, telephone -type block. For
terminal frame mounting, each block is furnished with
mounting hardware.
Cat. No. 7118765 -G1 Power Terminal Board
This unit consists of an eight-terminal, screw -type
terminal board, and marker strip. Mounting hardware is included with each terminal board for mounting on the Type PR -4 -A terminal board frame.
Cat. No. 7460330 -G4 Door -interlock Switch Kit
This kit consists of mounting hardware and an interlock switch which can be attached at either the front
or the rear of the Type PR -1 -A cabinet rack so that
high -voltage circuits will be de-energized when either
the front or the rear doors are opened. The stiffening
channel on both the front and the rear doors are wide
enough to permit the mounting of from one to three
General Electric door interlock switch kits for either
door.
AUDIO
Shelves
and
Cabinet Rack
Type
PR -1 -A
Cabinetry
and Accessory Items
Cat. No. 7485321 -G2 Blower Kit
HOW TO ORDER
This kit consists of aluminum plate baffles, rubber
molding, blower, and filter. The blower is mounted on
a plate which, in turn, is mounted on top of the Type
PR -1 -A cabinet rack. The blower is operated by a
1 /50 -hp, 1550 -rpm, 115 -volt single -phase 50!60- cycle,
50 -watt motor fitted with composition lifetime bearings and delivering 400 CFM of air. The filter is cornprised of 919d -inch by 15,96-inch by 1 -inch replaceable type filter, mounting frame, and hardware for mounting on inside bottom of rear door.
When ordering, please specify:
Type
PR -1A
Cat. No. 7140995 -G1 Filter
Available for use without blower in negative pressure systems.
Cat. No. 7772418 -P1 to Pl l "Bath Tub"
Type chassis mounting brackets. These are the
brackets which are available where throughout the
data book references are made to brackets available to
adapt chassis to RCA rack mounting. To adapt a
General Electric chassis, the pair of normally included
short brackets are removed and two of the following
deep brackets are substituted in their place. Mounted
in any 19 -inch rack with competitive chassis, which
have permanently attached deep brackets, the vertical
front surfaces of the two makes of chassis will be in the
same plane. For information in ordering brackets for
chassis of various height, the following table is listed:
Height of
Chassis
Inches
3%
5%
Rack
Units
2
7
3
4
8%
5
10'9
6
12%
7
14
8
15%
17!z
19%
9
10
21
12
11
Page A309
Order Two Brackets
Cat. No.
Description
Cabinet rack. The Type
PR-l-A includes one cabinet shell and rear door;
one pair equipment
mounting angles, Type
PR -7 -A; two angles (to
mount PR -4 -A frame);
mounting hardware and
two instruction books.
ACCESSORIES
Type
Description
Hinged panel assembly
(seven -inch, four rack
units, in height)
PR -3 -A
Front door
PR -4 -A
Terminal board frame
PR -5 -A
Wiring duct
PR -7 -A
Pair of equipment mounting angles. Type PR -7 -A
includes two angles; and
mounting hardware.
FA- 6- A/B /C /D /E /F /G Blank panels for filling
blanks when front mounting other equipment.
PR -2 -A
7772418 -P1
7772418 -P2
7772418 -P3
7772418 -P4
7772418 -P5
7772418 -P6
7772418 -P7
7772418 -P8
7772418 -P9
7772418 -P10
7772418 -P11
www.americanradiohistory.com
Shelves
and
Cabinetry
Cabinet Rack
Type PR -1 -A and Accessory Items
Page A310
FRONT DOOR TYPE PR -3 -A
MAY BE HINGED ON EITHER
SIDE OF CABINET
CUTOUT IN BOTTOM FOR COOLING
AND CABLES AND WIRES
ANGLES CAN NOT BE
MOUNTED IN FRONT
POSITION WHEN FRONT
_
'
DOOR IS USED
EQUIP MTG ANGLES
TYPE PR-7 -A
MAY BE MOUNTED IN
3 POSITIONS
'1
J
3 SCREWS
I/4 "- 20X1
/\
3 LOCKWASHERS
2
41'1'19.1"l'in'Ir
III
*8 -32 X 3/4"
_1!
I
4 NUTS
4 LOCK WASHERS'
3/8°
_
`'
1.-'
*I2 -24X 3/8°
4 SCREWS
i
!
I
a
3 SCREWS
R8 -32
3 SCREWS
X
5/8°
3 WASHERS
3 LOCK WASHERS
8 -32 X 3/8'.
5LOCKWASHERS
W
CABLING STRAP
TYPE PR -8 -A
X
X
2 LOCKWASHERS
4 SCREWS
73 "LG
SCREWS
*10-32
WIRING DUCT
TYPE PR -5 -A
._.,1
I/2 WIDE
2 POSITIONS
AVAILABLE ON
EACH SIDE OF
CABINET
_____
MA_
REAR
SECTION
A
DOOR
-A
ToALTERNATE
POSITIONS SHOWN TO
ENABLE MOUNTING OF 3
ADDITIONAL POWER TERMNAL
BOARDS IN LIEU OF 2
AUDIO TERMINAL BOARDS
BE MOVED
TERMINAL
BD.
FRAME
TYPE PR -4 -A, SHOWN
IN LOWEST POSITION
618181818IeIelel
18
TO BOTTOM OF
TERMINAL BD.
FRAME
POWER TERMINAL
BOARD MLK 711876561
REAR
TO TOP OF
SILL
AUDIO TERMINAL
BLOCK MLK 7118764G1
TO BOTTOM OF
WIRING DUCT
VIEW
(WITH REAR DOOR NOT SHOWN)
ACCESSORIES AVAILABLE ARE
CABINET RACK TYPE PR-I -A INCLUDES'
FRONT DOOR TYPE PR -3 -A
-REAR DOOR
TERMINAL BOARDEFRAME,TYPE PR-4 -A
PAR- EQUIPMENT MOUNTING ANGLES 77 1/2° LONG
PAIR -T8 FRAME MOUNTING ANGLES 40 3/4" LONG
44-$12-24 X 3/8"EQUIPMENT MTG. SCREWS
22N-HIGH
EHEpIINuJGEDEEOPAN LPRIDUST COVER, WITH MOUNTING HARDWARE
TYPE PR -7 -A
GABILIÑG STRAPS,TpE PRLDSA,
I
I
I
-A
NN7GG'
86
POWERTTERMIINALBBÓRDMLK117 7 5GI
BLANK PANELS- FA -6 -A- HEIGHTS OF 13/4
INCREMENTS FROM 123/32 TO 12 7/32
11
Installation of accessories in cabinet rack, Type
PR -1-A
Shelves
and
AUDIO
Cabinet Rack
Type
PR -1 -A
Cabinetry
and Accessory Items
Page A311
23.3/8"
3-17/32"
--14-13/16"-
L
--
4
r
.3/4-
_
CUTOUT
BOTTOM
f
4.3y/16
N
VENTILATION
(PENINO
IN TOP
d
168/11'
rr
2H/2
IHUB-
REMOVE ABLE
DUST PLATE
23/4"
w3/BSECTION A-A
22"
TOP VIEW
_______,__:_=
GDG
b
L___
HS'
g
4:1
o
Ir
i
8
00 0o
-9
8
g0
MOO
-1/16 OPENING FRONT
B REAR MN
113.1
8"
. --17-3/11 - 13ETWEEN
77-7-I/B"
ANGLES MN
-
-
OPENING
FRONT B REAR
12 -24 HOLES IN EACH
2 TERM BD
FRAME MTG ANGLES
SAME HOLE SPACING AS
EQUIP MTG ANGLES
s
4
OF THE
I
I
PERFORATED AREA
IN REAR DOOR I/O" SO
HOLES ON -CENTERS
I
WI
I
TERMINAL Bp
FRAME wTG ANGLES
Ma
kW=
DO
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r
r
------II-;-L,-_--lijJ
--I
1
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á
-8
12
I-I/4'
I-1N
22
22 V4"
2314"
I
NO-24 92 HOLES
N
EACH OF 2 FOLIO.
MTG ANGLES.
OCO
.44-5/16
3.
21
w
---IB-YIfi"
COCO
I
7
mm
cco
SIDE SEW
VIEW AT "B")
FRONT HEW
Outline of cabinet rack, Type PR1 -A
www.americanradiohistory.com
S
Shelves
and
Cabinet Rack
Cabinetry
Type
Page A312
PR -1
-A and Accessory Items
HORIZONTAL SECTION
(CABINET RACK TYPE PR
REAR DOOR
CABLING
STRAP
TYPE
PR-8 A 23
32
-I -A)
\
I
I6 1CLEARANCE TO OPEN COVER CATCHES
9N-
_
POSITIONS
AVAILABLE ON EACH
SIDE OF CABINET FOR
MOUNTING CABLING
STRAPS IN LIEU OF
WIRING DUCTS
16é
BETWEEN COVER CATCHES
CLEARANCE TO REMOVE WIRING
DUCT COVERS
¿
---
-
------1
132
TYPICAL PLUG IN AMPLIFIER
Milri
TERMINAL BOARD
FRAME MTG ANGLE
IN REAR POSITION
r..1
'
I
EQUIPMENT SHELF
=1N
Ì
11
.L-I
1421
T
I
N
I
TERMINAL BOARD
FRAME TYPE PR -4 -A
WITH TERMINAL
BLOCKS AND TERMINAL
30ARDS INSTALLED
4
I
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3
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i6
I6
I
N
I
LLL
__
2011
_
17
I8
_-_--.
w-- -_.__--_-- ___-
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-
-
-
IN FRONT POSITION
III
__
REAR DOOR
-.
-
_.
WIRING DUCT
i
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3
lp
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-
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TYPE PR -5 -A
ti
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,
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SUPPLY
TERMINAL BD FRAME
_ _
i
ltl/
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I
_
rr
.
'if
MTG ANGLES OR
EQUIP MTG ANGLES
IN REAR POSITION
::1
_
I
TYPICAL POWER
,e4.
I I
',mg
EQUIP MTG. ANGLE
22
-
-
,
D
-
BETWEEN MTG HOLES
r
rl
32
asssssI
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1916 MIN
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-]
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TYPICAL AUDIO
AMPLIFIER CHASSIS
I
TYPICAL JACK STRIP
-- .-J
11
.-J
1!
EQUIP MTG ANGLES
INTERMEDIATE
POSITION
-IN
FRONT DOOR TYPE PR -3 -A
HORIZONTAL SECTION
(CABINET RACK TYPE PR -I -A WITH FRONT DOOR TYPE PR -3-A)
Inside clearances in cabinet rack, Type
PR -1 -A,
with accessories installed
www.americanradiohistory.com
Shelves
and
Cabinetry
AUDIO
Control Console Base Cabinets
Types PR- 16 -B /C,
Type
FEATURES
Pleasing, functional appearance
Cabinets and desks mate with other General Electric
cabinetry and are designed to match in appearance
and operating levels. Ample leg room, correctly designed desk height, and control mounting angle minimize operator fatigue and speed operations.
Block built design
Cabinets and desk are mated so that they may be
bolted together in a line or used as single units. Turret is
designed to fit and fasten to base cabinet or desk.
Designed for ease of installation and maintenance
Ample and convenient ports (in bottom, rear, and both
sides) for cable entrances. The Type PR -16 -B C both
have two cutouts in the metal part of the desk top; the
Type PR -16 -C has these openings covered with a removable metal panel and a linoleum top. Removal of
linoleum and panel provide opening for flush surface
mounting of control equipment. Dividing strip (between
the two openings on the desk top) is readily removed
for installation of single larger control units. Type PR16-B C front and rear panels are removable for equipment installation and service.
Turret cabinet mounted control panel may be tilted
forward
turret cabinet accepts piano hinge or
throw -out type mounted panels.
The Type PR -17 -A
RETMA- Standard 19 -inch rack mounting facilities in
Type PR -16 -B C base cabinet
Equipment mounting angles are provided in base
cabinet for mounting of chassis and associated equipment. Mounting angles may be moved forward or
backward three inches from center position.
All cabinets and desks sturdily constructed of steel
Easily cleaned desk tops. Smooth matte black linoleum
desk tops are easily cleaned.
WHERE TO USE
The General Electric control console cabinets,
Types PR -16 -B C, PR -17 -A, and desk, Type PR18-A are matched units designed to support and permit surface, internal or angle mounting of General
Electric audio and video control equipment.
The end caps, Types PR -11 -A and PR -11 -B are
designed to dress up the appearance of control console
base cabinets and to serve as a support for the ends of
the Type PR -18 -A desk.
DESCRIPTION
PR -16 -B C Control Console Base Cabinets
The Type PR -16 -B C control console base cabinets
Page A313
PR -17 -A
are designed to mount and house video control panels,
relays, and chassis. They also serve as the floor mounted support of the Type PR -17 -A turret cabinet.
These two base cabinets serve as the basic cabinets
for most horizontally operated video controls. When
used with the Type PR -17 -A turret cabinet, audio or
video control panels may be flush -mounted at an angle
of 60 degrees from the horizontal to improve operational efficiency.
PR -16 -B Base
Cabinet
The Type PR -16 -B base cabinet consists of a vertical cabinet 1914 inches wide, 28,;; inches high, and
21;3, inches deep. The front top of this cabinet protrudes out to form a desk surface 1914 inches wide and
36 inches deep. The desk surface is covered with
smooth matte black linoleum except for two panel
openings, providing desk mounting space for two 51
by 15 -inch studio -control panels. If only one control
panel is used, a blank panel and dress panel are provided to cover the remaining space.
The center dividing strip between the two openings
is held in place by four screws and nuts. This strip may
be readily removed to provide space for an 11- by 15inch control panel.
Both front and rear base cabinet panels are removable for installation and service of equipment. The
rear panel contains ventilation grilles at both top and
bottom. Internally there are two equipment angle
mounting brackets for mounting standard size rack
panels or chassis up to 24 inches in height. These
angles, normally located near the center of the cabinet,
may be moved forward or backward 3 inches either
side of center. They may also be reversed so that
equipment may be mounted from the front or the rear
of the cabinet. Distance between the inner edges of
the mounting brackets is 175A inches.
Cable ports are located on both sides and the rear.
The side ports line up with those of other General
Electric cabinets (such as the Type PR- 12 -A). Buttons are provided to close the unused ports. Holes are
provided on either side for attachment of other units
or end caps. The bottom is open for passage of interconnecting cables. In the bottom corners are four ,inch- diameter mounting holes for rigid floor mounting.
-
1
Type
PR -16 -C Base
Cabinet
The PR -16 -C base cabinet is identical to the Type
PR -16 -B base cabinet, except for the desk top. The
entire surface of the PR -16 -C desk top is covered with
smooth matte black linoleum. Underneath the linoleum
is a blank -metal panel 10 ,, inches by 15 inches, which
covers two equipment mounting holes identical in size
to those in the Type PR -16 -B base cabinet. Each
opening is 5 inches by 1378 inches in size and, with
removal of the linoleum and blank -metal panel, will
accept two standard 51,-inch by 15 -inch control
panels. As in the Type PR -16 -B cabinet, the dividing
strip is also readily removed to make way for a single
larger 11 -inch by 15 -inch control panel. This cabinet is
primarily intended for use where additional desk space
is required, yet it contains the necessary openings for
control mounting for future use.
,
Type
PR -17 -A
Turret Cabinet
The Type PR -17 -A turret cabinet is a desk -mounted
unit with hinged front brackets for mounting audio
and master -control panels. The unit mounts on the
Type PR -16 -B C base cabinet and is secured to the
cabinet through four mounting holes mating those in
the base cabinet. The bottom of this cabinet contains a
14 -inch by 183.1 -inch opening for ease in cable installation and maintenance. The cabinet is supplied with
throw -out type hinges, with additional provision for
mounting panels with a piano hinge. When using the
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Shelves
and
Control Console Base Cabinets
Cabinetry
Types PR- 16 -B /C,
Page A314
latter type hinge, the throw -out hinge may be removed
1
if necessary.
This cabinet will accept flush -front mounting audio
or video equipment of 14 inch height and 19 inch
width, when mounted on throw -out or piano hinge.
It may also be mounted on the Type PR -18 -A desk.
Type PR -18-A Desk
The Type PR-18 -A desk is primarily designed to
support the larger General Electric Type BC -11 -A
audio control console. It will, in addition, accommo-
See
-A and
PR -11 -B End
The PR- 16 -B¡C base cabinets are floor mounting units.
The PR-17 -A is desk mounting.
The PR-18 -A is floor mounting.
The PR-11 -A 8s B mount on the sides of base cabinets and are
not equipped with holes for floor mounting.
CONSTRUCTION
Formed welded -steel construction. Type PR -18 -A desk top,
plywood with 2 -inch angle iron reinforcement. All
operating desk surfaces covered with matte black linoleum.
34 -inch
FINISH
General Electric metalustre blue.
VENTILATION
All units are cooled by natural air convection currents. Rear
panels of PR- 16 -B,'C contain ventilation grilles at top and
bottom.
HOW TO ORDER
When ordering, please specify:
Type PR -16 -B control console base cabinet
(The Type number includes one cabinet with two
internal equipment mounting brackets, one subpanel,
one dress panel, cable knock -out buttons, and installa-
Caps
The Types PR- -A and PR -11 -B are, respectively,
right and left end caps. These end caps are formed
steel sections used to dress up the appearance of the
Type PR- 16 -B /C base cabinets as well as other cabinets of this type in the General Electric equipment
line. Only two caps are required to finish off the end
appearances of a single Type PR -16 -B; C base cabinet
or a group of them bolted together.
The Type PR -11 -A and B end caps are used as end
supports for the Type PR -18 -A desk.
MECHANICAL SPECIFICATIONS
1 1
UNITS
1
tion and operating instructions.)
Type
Type
PR -11
-A right -end cap
Type PR-11-11 left -end cap
(The Type number includes the end cap, mounting
hardware, and installation instructions.)
Type PR -17 -A turret cabinet
(The Type number includes the cabinet, throw out hinges, mounting hardware, and installation and
operating instructions.)
PR -18-A desk cabinet
(The Type number includes the top, rear panel, one
Type PR -11 -A end cap, one Type PR -11 -B end cap,
and installation and operating instructions.)
Type
hinge, and mounting hardware).
39-
control console base cabinet
(The Type number includes the end cap, mounting
hardware, and installation instructions.)
buttons).
1 -Type PR -16 -C base cabinet (includes the cabinet with top
completely covered by linoleum, one subpanel, a removable
front and rear panel, two equipment mounting brackets,
and cable knock -out buttons).
1 -Type PR -11 -A right -end cap.
1 -Type PR -11 -B left -end cap.
1 -Type PR -17 -A turret cabinet (includes cabinet, throw -out
a
PR -16 -C
(The Type number includes one cabinet with two
internal equipment mounting brackets, one subpanel,
cable knock -out buttons, and installation and operating instructions.)
Type PR -16 -B base cabinet (includes the cabinet, one sub panel, one dress panel, a removable front and rear panel,
two equipment mounting brackets, and cable knock -out
r
drawings.
MOUNTING
cabinets.
PR -11
Type PR -18 -A desk (includes one PR -11 -A and one Type
PR -11 -B end cap and a top and rear panel).
DIMENSIONS
date the Type PR -17 -A turret cabinet.
The desk top consists of a sturdily constructed
wooden top, surfaced with matte black linoleum. It is
supported at the ends by the use of Type PR -11 -A and
Type PR -11 -B end caps. It is enclosed by a rear metal
panel. The desk top itself is hardwood -edged, 34-inch
plywood, reinforced with 2 -inch angle iron. The unit is
39 inches wide (44 inches with end caps), 28ís6 inches
high and 36 inches deep. This unit may be used as an
all- purpose desk to support other video or audio
Types
PR -17 -A
a"
IS2ii2..
32"
P
.
18
END CAP
PR -II A/B
A
01I1-1/2"
NO FLOOR
MOUNTING HOLES
N END CAPS.
MAY BE ADDED
F NEEDED
14- 271/2"
36"
Outline drawing, Type
PR -18 -A desk
www.americanradiohistory.com
Shelves
and
Cabinetry
AUDIO
Control Console Base Cabinets
Types PR- 16 -B /C, PR -17 -A
Page A315
COMPONENTS
Dimensions in Inches
Type
PR -18 -A
in
Depth
Height
36
28T}
29
271/2
36
28
Types TC -21 -A,
TC -28 -A,
TC -29 -A,
TC -34 -A,
TC -35 -A,
TC -39 -A.
TC -40 -A panels
36
28
TypesTC -15A,
TC -36A and
transmitter
control panels
24
e
36- by 39 -inch desk top of
hardwood edged 3/4 -inch plywood reinforced with 2 -inch
angle iron and covered with
/s -inch matte black linoleum.
Weight
For Use with
Description
Type
BC -11 -A
console
Width
44
Lb
150
desk
End Caps
Metal panel and dividing strip under
linoleum readily removed
The end cap description is
identical to that of the end
caps, left and right, on the
Type
PR
-18 -A desk.
Type PR -10 -A B C,
Type PR -12 -A and
Type PR -16 -B C
base cabinets
21/2
35
Control Console
Linoleum can be cut and a 10 16
by 15 -inch metal panel under
linoleum can be exposed two
5 by 13%-inch opening. Also,
the dividing strip can be removed to make one 101/2- by
13% -inch opening (to fit an
11- by 15 -inch panel(.
Type
Type
Type
PR -11 -B
PR -16 -C
PR -11-A
left -end
console
cabinet
right -end
cap
Other cabinets
where added desk
space is required.
19'
60
;
19%
60
12%
19'/4
30
cap
and
blue- topped
Sub -panel
dress panel can be removed
to expose second 5- by 13 %inch opening. Dividing strip can
be removed to make one 101/2by 13%-inch opening (to fit an
11- by 15 -inch panel).
Type PR -16 -B console cabinet
,'f - by 19'% -inch external
dimensions of front surface.
14
by 18 -inch opening in
front surface.
13
Type
PR
-
-17 -A turret cabinet
www.americanradiohistory.com
Shelves
and
Control Console Base Cabinets
Cabinetry
Types PR-16-B/C, PR-17-A
Page A316
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fa
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Shelves
and
AUDIO
Control Console Base Cabinets
Types PR- 16 -B /C,
Cabinetry
PR -17 -A
Page A317
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:
AUDIO
Microphones
and
Accessories
Microphone Cable, Plugs, and Receptacle
Type FA -16-A,
Type FA -15 -A
Type FA -16 -C
B
Page A401
MICROPHONE CABLE
TYPE. FA -15 -A
BLACK RUBBER
GRS
COMPOUND
COTTON WRAP
TINNED, BRAIDED, COPPER
SHIELD
COTTON WRAP
COTTON FILLER
RUBBER GRS COMPOUND, INSULATION,
ONE RED, ONE BLACK,
COTTON WRAP
* 20 AWG
TINNED STRANDED
(16 STRAND) COPPER CONDUCTOR
Microphone cable, Type FA -15 -A
Male microphone plug, Type FA -16 -A, female microphone plug,
Type FA -16 -B, and microphone wall receptacle, Type FA -16 -C
FEATURES
straight in use; but high flexibility permits easy
coiling for storage purposes
Ruggedly constructed for long, efficient service
Tough outer GRS compound jacket resists abrasion
and abuse giving thorough protection to inside
shielding and conductors
Lies
WHERE TO USE
The General Electric Type FA -15 -A microphone
cable is a two -conductor, shielded, rubber- covered,
flexible, water -proof cable designed primarily for use
with low impedance microphones in television and
broadcast studios. It may be used also for the make -up
of extension cables and as replacement for old cables.
MECHANICAL AND ELECTRICAL
SPECIFICATIONS
LOT LENGTH
2
I Ir,
I
li,
FEATURES
Easily installed
Large solder pots on pin ends permit easy installation
with excellent electrical and mechanical connection of
wires.
Positive locking device
push of the male plug into the wall receptacle or
mating plug automatically locks the two together.
A
Quick, easy disconnect
Thumb latch allows immediate disconnect of lock and
easy withdrawal of plug.
Rugged construction
Steel shell with phenolic -mounted contacts assures long,
dependable life.
VOLTAGE RATING
600 volts,
Rubber bushed cable clamp
OUTSIDE DIAMETER
The Clamp takes strain from connections and aids in
0.3211 -inch
This cable consists of two No. 20 AWG 116 strands per conductors, stranded, tinned copper conductors with a cotton wrap
over each conductor. Rubber GRS compound insulation is placed
over the cotton wrap; insulation colored white on one conductor,
black on the other. The two conductors are then twisted with
cotton fillers and a cotton wrap is placed over them. A tinned
copper braided shield is placed over this assembly. This shield
is covered with another cotton wrap. The entire assembly is
enclosed within a black rubber GRS compound jacket.
HOW TO ORDER
When ordering, please specify:
spools (250 feet each) of Type FA -15 -A microphone cable.
longing cable life. Clamp
is
prointegral part of plug shell.
Large pin -type male contacts
Assure good connections with mating plug or receptacle.
WHERE TO USE
General Electric microphone plugs and wall receptacle are ruggedly designed units patterned after a
trouble -free type of self -locking, quick disconnect plug,
and receptacle. They are furnished with three standard contacts and have either a satin chrome or zinc
plate finish.
Microphones
and
Accessories
Microphone Cable, Plugs, and Receptacle
Type FA -16 -A,
Type FA -15 -A
Page A402
MECHANICAL AND ELECTRICAL
Type FA -16 -C
B
LENGTH OF ENGAGEMENT
SPECIFICATIONS
DI
RUBBER REDUCING
BUSHING
1/2 "M
LENGTH OF
ENGAGEMEN I
RUBBER REDUCING
I" DIA
BUSHING
2
9/32-CABLE ENTRY
2- /4 "APPROX:
I
Female microphone plug, Type FA -16 -B
16 CABLE
ENTRY
232
32
Male microphone plug, Type FA -16 -A
The steel shell and zinc cable clamp are finished in
satin chrome. Phenolic insulation is used to mount the
contact pins. Cable entry is ,',; inch, through rubber
reducing bushing. Shell has circular groove in interior
to accept latch of female connector or wall receptacle.
The three male contacts are so spaced that they
cannot be inserted in a receptacle in the wrong position. The contacts terminate in tinned solder pots for
wire connections. Dimensions shown on previous
drawing.
The die -cast zinc shell is finished in satin chrome.
Insulation is black phenolic compound with contacts
anchored within. Cable entry is ás inch, through a
rubber reducing bushing. A thumb -operated locking
latch locks on inside rim of mating male plug shell
when the units are pushed together. Encasements of
the three female contacts are so located that the male
plug cannot be wrongly positioned on insertion. The
contact encasements terminate in solder pots for wire
connections. See preceding drawing for dimensions.
LATCH LOCKING
DEVICE
SOLDER POTS
EXTEND A MAX.
OF I/4" FROM REAR
OF SHELL
.
a
-IN
ml%
MTG. BRACKET FOR
STD OUTLET BOX
24
\#6 -32
X
3/8" OVAL
HEAD MACHINE SCREW
2 SCREWS FURNISHED
Microphone wall receptacle, Type FA -16 -C
This unit is a single -gang, flush- mounting, wall
receptacle with female latch- locking unit. It has a die cast zinc shell and is finished in zinc plate. Insulation
is black phenolic compound. Encasements of the three
female contacts terminate in solder pots. A male plug
is automatically locked into this receptacle by the
locking latch engaging in a groove on the inside rim of
the plug shell when the plug is inserted. The thumb
operated latch releases the lock. This receptacle fits
all standard wall outlet boxes similar to General
-
Electric Outlet Box SP -5800. See drawing on Type
FA 16-C receptacles for dimensions.
HOW TO ORDER
When ordering, please specify:
Microphone plug, male, Type FA -16 -A
Microphone plug, female, Type FA -16 -B
Microphone wall receptacle, female, Type FA -16 -C
VIDEO
Speakers
and
Accessories
Monitoring and Wall Speakers
Types
FS -1
-B and
FS -2 -B
Page A501
Monitoring speaker, Type FS1 -B (Type
FEATURES
Monitoring Speaker, Type
Rich
FS -4 -A
cabinet)
FEATURES
FS -1
Studio Wall Speaker, Type
-B
full bass
Assured by use of ample cabinet volume and bass reflex design.
Wide range response
Use of famous General Electric speaker Type 1201A
provides a uniform response, free from objectionable
peaks, over the useful range of 50 to 13,000 cycles per
second.
High wattage capacity
Non -warping aluminum foil base voice coil
FS -2 -B
Good sound di stribution
Cabinet front sloped for best sound distribution.
Good frequency reproduction
Uses Genercl Electric 1201A speaker.
Attractively styled cabinet
Attractive walnut- finish wood used in cabinet con-
struction.
Line -to- voice -coil transformer included
Economical
is
unaffected
Speaker cnd cabinet combination low
in
price.
by changes in moisture or temperature.
Low driving power required
Speaker is highly efficient.
Contemporary styling of cabinet
Carefully selected woods and contemporary cabinet
styling complement the appearance of any studio.
Line -to- voice -coil transformer included
WHERE TO USE
Monitoring Speaker, Type FS -1 -B
The Type FS -1 -B monitoring speaker is designed
for critical high -quality monitoring of broadcast program material in AM -FM and TV broadcast studios.
It is ideally suited for every application requiring a
pleasing, wide range response coupled with an attrac-
tive appearance. The Type FS -1 -B monitoring speaker
will provide unexcelled reproduction of music and
speech in clients' rooms, control rooms, and studios.
Its range extends from 50 to 13,000 cps.
Studio Wall Speaker, Type
FS -2 -A
The Type FS -2 -A studio wall speaker is a low -cost
speaker and housing combination for general -purpose
use in studios, offices, and recording rooms of broadcast studios.
www.americanradiohistory.com
Studie Wall Speaker, Type FS2B
(FS3A Housing)
Speakers
and
Monitoring and Wall Speakers
Accessories
Types
Page A502
FS -1
-B and
FS -2 -B
MECHANICAL SPECIFICATIONS
UNITS
Type FS-1 -B monitoring speaker including floor cabinet,
speaker, and line -to- voice -coil transformer.
Type FS -2 -B studio wall speaker, including wall mounting
cabinet, speaker, and line -to- voice -coil transformer.
Type FS -3 -A wall speaker housing only.
Type FS -4-A monitoring speaker cabinet only.
DIMENSIONS (in inches)
TYPE FS-2-8
TYPE FS -1 -B
Speaker:
Cabinet:
WEIGHT
12
12
1412
26
25
18
lbs approx
10
Depth:
Height:
Width:
70
93t
14%
lbs approx
MOUNTING
Type FS -1 -B floor mounting.
Type FS -2 -B. Wall mounting with drilled holes to facilitate
easy mounting or take -down.
FINISH
Walnut.
CONNECTIONS
Studio wall speaker, Type ES-2-B, rear, showing voice -coil
transformer
DESCRIPTION
Monitor Speaker, Type FS -1 -B
The Type FS -1 -B monitoring speaker is composed
of the Type FS -4 -A monitoring speaker cabinet, a
1201A loudspeaker, and a Type FA -42 -A line -tovoice -coil transformer.
The speaker used in the cabinet employs a curvalinear molded cone for efficient dispersion of its wide
range reproduction. The heavy Alnico V permanent
magnet provides a high sensitivity with reliable, quiet
operation.
The interior surfaces of the cabinet are treated with
special sound -absorptive material.
While the cabinet is designed for floor mounting, it
may be readily wall mounted, if required.
Studio Wall Speaker, Type
FS -2 -B
The Type FS -2 -B studio wall speaker consists of a
Type FS -3 -A wall speaker housing, a 1201A speaker
and a Type FA -42 -A line -to-voice -coil transformer.
The cabinet is especially constructed and braced for
wall mounting. Its sloping front panel assures good
distribution of sound when the speaker is located out
of the way at or near ceiling level. Its external walnut
finish harmonizes pleasingly with other studio fixtures.
A line -to-voice -coil transformer, included with this
model, will provide correct matching to several line
impedances or parallel speaker operation.
Type FS-1 -B and Type FS -2 -B
former taps.
solder terminals on trans-
ELECTRICAL SPECIFICATIONS
TYPES FS -1 -B
AND
FS -2 -B
Frequency response: 50-13,000 cps.
Power handling capacity: 25 watts, music and speech.
Field: Alnico V permanent magnet, 14.5 ounces.
TRANSFORMER INPUT IMPEDANCE
600 1200 1800 2400 ohms.
HOW TO ORDER
When ordering, please specify:
Type FS -1 -B monitoring speaker. (The type number includes one Type FS -4 -A cabinet, one 1201A
speaker, one Type FA -42 -A line -to- voice -coil transformer, and installation and operating instructions.)
Type FS -2 -B studio wall speaker. (The Type number includes one Type FS -3 -A wall housing, one
1201A speaker, one Type FA -42 -A line -to-voice -coil
transformer, and installation and operating instructions.)
Type FS -3 -A wall speaker housing.
Type FS -4 -A monitoring speaker cabinet.
ACCESSORIES
Type FA -19 -J interconnecting cable.
VIDEO
Speakers
Speakers
and
Accessories
Types 850, 1201A, and 1203A
Page A503
Cut -away view speaker, Type 1201A
Speaker, Type 1201A
FEATURES
High wattage handling capacity
Made possible by use of non -warping aluminum foil
base voice coils.
Faithful reproduction
Assured by molded,
Electric cones.
scientifically designed General
High efficiency
Due to liberal use of Alnico V magnet material.
Rigidly constructed
All- welded construction insures rigidity and provides
WHERE TO USE
General Electric loudspeakers are designed for
critical high quality monitoring of broadcast program
material in AM -FM and TV broadcast studios. They
may be depended upon to provide excellent reproduction of music and speech in recording, control, and
studio monitoring applications.
The Types 850, 1201A and 1203A speakers are wide range speakers for use in broadcast control and studio
monitoring.
optimum controlled flux density.
Attractive appearance
Lustrous finish is specially protected to preserve beauty
DESCRIPTION
and effectiveness.
Wide range
The 1201A and 1203A speakers uniformly cover the
frequency range from 50 to 13,000 cycles -per- second.
MODEL
1201 A LOUDSPEAKER
RESPONSE ON AXIS -18" FROM
IN
DEAD ROOM
INFINITE
CONE
BAFFLE
AVERAGED
20
General Electric loudspeakers are designed by audio
engineers and produced under exacting conditions of
quality control.
100
CURVE
1000
FREQUENCY IN CYCLES PER SECOND
10000
20000
Speakers
and
A ccessories
Speakers
Page A504
Types 850, 1201A, and 1203A
Speaker, Type 850
The Type 850 speaker is a wide range unit, 8 inches
in diameter with a 15 -watt handling capacity.
Speakers, Types 1201A and 1203A
The Type 1201A and 1203A speakers are wide
range units, 12 inches in diameter and with 25 -watt
handling capacities. They differ only in their Alnico V
magnet weight; the 1201A having a 14.5 -ounce magnet compared to a 9 -ounce magnet in the 1203A, with
a consequent increase in efficiency in the 1201A.
All speakers employ non -warping aluminum foil
base voice coils with molded, scientifically designed
circular cones. All- welded frame construction is employed to insure rigidity and controlled flux density.
Alnico V magnet material is used for increased
efficiency.
Due to careful design and quality control in manufacture, these speakers offer a uniform response, with
freedom from objectionable peaks over their useful
response ranges.
MECHANICAL AND ELECTRICAL
SPECIFICATIONS
UNITS
Wide range speakers: Types 850, 1201A, 1203A.
MOUNTING
All speakers are equipped with four mounting holes on the
circumference of the frame designed to accept No. 8 machine
screws.
DIMENSIONS AND WEIGHTS
Diameter
Over -all
Speaker, Type 850
Depth
Mtg.
Gasket
Hole
Yok
Size
Centers
(In inches)
((In inches)
7 }1
1237y
12372
11 A'e
11
T
850
1201A
1203A
or Coer
(In inches)
75s
Type*
inches)
Shape'
Cone
Wig'
lb 10 oz
8 oz
lb 2 oz
3 s.l
2
5%
6 lb
57K
5
Power
V.C.
Rating D(In
Baffle
Open
Ohms
inches)
8.0
67/8
15w
1
8
Round
6.8 oz
850t
14
8.0 1031
25w
Round 14.5 oz
12
1201Aí
1%
8.0 10 s.¡
25w
Round
9.0 oz
12
1203At
The General Electric Company manufactures a complete line of
original and replacement speakers in a variety of shapes, sizes,
and ratings not shown here. For information concerning these
latter speakers, please consult your local General Electric
distributor.
t Wide range speakers recommended for broadcast studio and
monitoring applications.
inches)
CONNECTIONS
Types 1201A, 850 and 1203A
Screw terminals.
HOW TO ORDER
When ordering, please specify:
Type
,
Wide range speaker
ACCESSORIES
V.C.
Alnico V
Sizes
(In
Shipping
Weight
Type FS-4 -A monitoring speaker cabinet (for 12 -inch speaker).
speaker).
speaker
Type FA 42 A line-to-voice-coil
o- voice -coil transformerh
Type FA -19 -J interconnecting cable.
AUDIO
Transcription
Transcription Equalizer
Page A601
Type FA -12 -B
Transcription equalizer, Type FA -12 -8
FEATURES
Pleasing record reproduction -full low- frequency
response and adjustable high- frequency response
Easy to install -single unit construction
Low hum pickup because of adequate magnetic
shielding
Connections simplified- outputs may be run balanced or unbalanced
Convenient to use-connects to any microphone
pre -amplifier
WHERE TO USE
The General Electric Type FA -12 -B transcription
equalizer is an adjustable network for use with professional -type General Electric cartridges, 4GS -01D,
4GS -02D and 4GD- 01D -02D, for broadcast reproduction of lateral transcriptions and records.
DESCRIPTION
The Type FA -12 -B transcription equalizer is a
single unit housed in a rectangular steel case. It has a
low - impedance output which will work into the un-
loaded input of any microphone pre -amplifier. It
includes a four -position switch which provides control
of high- frequency response.
The FLAT position provides essentially flat high frequency response from material recorded at constant
velocity above 700 cps. The NAB position provides an
essentially flat reproduction of material recorded in
accordance with the NAB lateral curve. This position
may also be used for reproduction of 78 -rpm vinylite
base and "hi -fi" records. The GOOD RECORDS
position provides a high- frequency response somewhat more attenuated than that given by the NAB
position. The fourth position, marked POOR RECORDS, provides a high- frequency response considerably more attenuated than that given by the
NAB position. (See average performance characteristic curves.)
All switch positions provide low- frequency reponse
essentially the complement of the NAB curve.
Transcription
Transcription Equalizer
Page A602
Type FA -12 -A
Experience has shown that the NAB position is
ideal for high -quality transcriptions and both wide groove (0.003 -inch) and micro -groove (0.001 -inch)
types of records. For worn transcriptions and average
good records, the GOOD RECORDS position provides the most pleasing response. Noisy and distorted
records require the POOR RECORDS position. The
FLAT position is useful for the reproduction of instantaneous recordings and other special records cut
with a FLAT recording characteristic.
snodate various thicknesses of transcription turntable top
panels. A knob and escutcheon plate are supplied for mounting
above the transcription equalizer on the control surface of the
transcription turntable. External connections to the pickup and
to the amplifier are made on a terminal board located at the
bottom of the equalizer case. Although the equalizer components
are completely enclosed in a protective metal case containing
inner mu -metal shields, the removal of two case screws enables
rapid access to the components should servicing be necessary.
ELECTRICAL SPECIFICATIONS
OUTPUT CIRCUITS
Load Impedance
Designed to work into either a 150, 250- or 30 50 -ohm unloaded input
Output Connections
Balanced, or either side may be grounded
Output Level
An output level of approximately -55 VU maximum is
obtained when reproducing 78 rpm shellac records; -60
VU maximum from micro - groove records
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth
Length
Width
Weight
(In inches)
Can
Dial Plate
(In inches)
4¡a
3%
3%
3lb
3
TYPICAL REPRODUCTION RESPONSE
2
See average performance characteristic curve.
MOUNTING
Tapped mounting holes are provided at the top (switch end)
of the case to enable mounting the Type FA -12 -B to the under
side of the top panel of a transcription turntable with its switch
shaft passing vertically through a clearance hole drilled in the
top panel. The switch shaft is made extra long so as to accom-
HOW TO ORDER
When ordering, please specify:
Type FA -12 -B transcription equalizer.
FLAT POS.
+5
REL
/-
o
DB
NARTB POS.
5
10
GOOD RECORDS
POS
15
POOR RECORDS POS.
50
100
500
5,000
1000
FREQUENCY IN
10,000
CPS
Average performance characteristics of the transcription equalizer with the "new orthophonic" test record and
General Electric 4GS -01D or 4GD- 01D-02D cartridge using the -mil diamond stylus
1
AUDIO
Transformers
Line -to -Line Transformer
Page A701
Type FA -40 -B
WHERE TO USE
The General Electric Type FA -40 -B line -to -line
transformer is designed for use as a high quality repeat
coil in telephone lines, or for isolation and impedance
matching in output circuits of low- and medium
-
level amplifiers.
MECHANICAL SPECIFICATIONS
DIMENSIONS (Over -all)
Height
Width
Depth
Weight
3% inches, maximum
2114 inches, maximum
2% inches, maximum
Approx l;;.á lb
Line-to-line transformer, Type FA -40 -B
HOW TO ORDER
When ordering, please specify:
Type FA -40 -B line -to -line transformer.
MOUNTING
No. 6-32 -8 tapped inserts
CONNECTIONS
PRI
ON
SEC
SEC
600
CT
ONUS
__J
L
MTG1
SCR
CENTER TAPS MAY
BE
GROUNOED AS DESIRED
IDM
JCUTS
/
L
#6-32 -6
-
TAPPED INSERTS
MOUNTING SURFACE
Installation drawing for transformer, Typo FA -40 -B
www.americanradiohistory.com
AUDIO
Transformers
Bridging -to -Line Transformers
Page A703
Type FA -41 -C
WHERE TO USE
The General Electric Type FA -41 -C bridging -toline transformer is designed for use in connecting
a 600- or 150 -ohm device across a low- impedance
program circuit without appreciably affecting the
performance of that circuit.
MECHANICAL SPECIFICATIONS
DIMENSIONS (Over -all)
Depth
Height
Width
Weight
2N inches
334 inches
2;e inches
Approx ;, lb
MOUNTING
No. 6 -32 tapped inserts
14-inch
ELECTRICAL SPECIFICATIONS
FREQUENCY RANGE
In excess of 50 to 15,000 cycles, ±
!
2
db
IMPEDANCES
20,000 ohms to 600 ohms
5,000 ohms to 150 ohms
MAXIMUM OPERATING
Bridging -to -line transformer, Type FA -41 -C
LEVEL
+15 dbm at 50 cycles on secondary (corresponds to approx
volts on 20,000 -ohm primary)
38
BRIDGING LOSS
19 db (See installation
drawing below)
HOW TO ORDER
When ordering, please specify:
Type FA -41 -C bridging -to -line transformer.
CONNECTIONS
See installation drawing below
CONNECTIONS
PRI.
BRIDGING LOSS:
SEC.
!
20.000
MI.
SEC.
I
ISO
OHMS CT
rr OHMS
,
L.
MTG.
MTGL
SCR.
PI
¡ 600 OHM LOAD
AMPLIFIER
!_J
y
r -.
SCR
CENTER TAPS MAY BE GROUNDED AS DESIRED
2i6 MAx
mlIIJ<I
e
20,000
OHMS
1
TAPPED INSERTS
DEEP
G s
I
7
Tiluer
o
0e -32 x.-
1-DIA
I
,
I
PI
^BRIDGING
LOSS
10
LOG-
-_-Es
s
216
I
7
36°
600 OHMS
3
_4_,
MAX
i
r;=.
AMPLIFIER
o
PI
s"
T,
5000
OHMS
T':
150 OHM LOAD
I
'WS
.G
!
DIA
2
19 db
P2
P2
CHASSIS CUTOUT
1
L
_
AJ
PI
BRIDGING LOSS
P2
ISO OHMS
Installation drawing for transformer, Type FA -41 -C
19 db
10 LOG
P2
AUDIO
Transformers
Line -to -Voice Coil Transformer
Page A705
Type FA -42 -A
FEATURES
Multiple primary taps. Permits paralleling of speakers across a single output
Multiple secondary taps. Permits use of transformer
with all common voice coil impedances
Terminal impedances clearly marked. All terminal
impedances are clearly marked on the coil adjacent
to the terminal
Frame bright plated to resist corrosion
WHERE TO USE
The General Electric Type FA -42 -A line -to -voice
coil transformer is designed to match a 600 -ohm amplifier output to single- or multiple- speaker voice coils. It
is
provided with multiple primary and secondary taps
Line -lo -voice coil transformer, Type FA -42 -A
for this purpose.
MECHANICAL SPECIFICATIONS
UNITS
DESCRIPTION
1
The General Electric Type FA -42 -A line -to -voice
coil transformer utilizes core and coil construction
with solder lug -type terminals.
Multiple primary terminals permit the use of from
one to four speakers across the output of any 600 -ohm
amplifier.
Multiple secondary terminals permit the proper
matching of any speaker with a voice coil impedance
range of from 3.2 ohms to 16 ohms. Three taps are provided for this purpose.
All terminals are situated on the coils and are clearly
marked for ready identification of their impedances.
Type FA-
12 -A
line -to -voice coil transformer
DIMENSIONS
Height
Length
2
Width
inches
334 inches
Weight
23
14
inches
oz
MOUNTING HOLES
Two
-
1
é -inch
diameter on
2
¡4 -inch
centers
CONNECTIONS
Solder -type terminals, protruding from coil
MARKINGS
Terminal impedances marked adjacent to them on coil surface
CONSTRUCTION
Open frame, core and coil construction
ELECTRICAL SPECIFICATIONS
PERFORMANCE
Frequency response: 2 db, 60 -8000 cps
Power handling capacity: 5 watts with less than
distortion
TRANSFORMER CIRCUIT
2400
1800
1200
PRIMARY IMPEDANCES
600 1200 181)0
16
8
3.2
600
C
C
3
2 10(1
ohms
SECONDARY IMPEDANCES
3.2
8'16 ohms
HOW TO ORDER
When ordering, please specify:
Type FA -42 -A line -to -voice coil transformer.
percent
Auxiliary
AUDIO
Equipment
Interconnecting Cables
Page A801
Types FA -19 -J, FA -19 -M, and FA -19 -R
Type FA -19 -J
Type FA -19 -M
Type FA-19-R
FEATURES
Small outside diameter of Types FA -19 -M and FA19-R enables use of greater number of cables in a
small conduit. Outside diameter only 0.152 inches
Easily stripped and prepared for soldering
Third bare conductor in full length contact with
shield provides excellent grounding in audio cables
(Types FA -19 -M and FA- 19 -R). No need to solder
ground to shield
Wrap- around shield in audio cables easily removed
during making of connection. No need to fray out
shield as with braided type
Audio cables insulated from each other by over -all
polyvinyl jackets on each cable. Permits common
grounding at one point
Sold in 500 -foot, nonreturnable spool lots
cables designed for use in low or intermediate level
audio circuits. Both cables are No. 22 AWG two conductor, shielded with over -all nylon jackets. The
Type FA -19 -M employs solid conductors, while the
Type FA -19 -R uses stranded conductors. A unique
feature of these two cables is the third, bare ground
wire included under the shielding and in contact with
it for the entire length of the cable.
TYPE:
FA -I9
DESCRIPTION
The Types FA -19 -M and FA -19 -R interconnecting
cables are small- diameter, two -conductor, shielded
-M
-R
POLYVINYL OVERALL JACKET
WRAP AROUND TINNED COPPER SHIELD
NYLON JACKET (EXTRUDED)
RED OR BLACK CELANESE WRAP AROUND OR BRAID
NYLON EXTRUDED JACKET
WHERE TO USE
The General Electric interconnecting cables, Types
FA -19 -J, FA -19 -M, and FA -19 -R are used for power,
audio, or circuit control connections. Each of the three
types has special characteristics and recommended
uses. All of the three cables are designed and manufactured to give long, efficient, trouble -free service. Types
FA -19 -M and FA -19 -R cables have been made with
very small outside diameters to permit their use in large
numbers in small conduits or other small- diameter
wiring channels.
FA -19
#22 AWG GROUND WIRE (IN
#22 STRANDED (FA- 19 -R), OR
SOLID
*
CONTACT WITH SHIELD)
SOLID (FA- 19- M),TINNED,
COPPER CONDUCTOR
Utilizes stranded bare ground wire.
The Type FA -19 -M is recommended for general purpose audio wiring within ducts, conduits, and
cabinets, where vibration is at a minimum. The Type
FA -19 -R is recommended for use inside cabinet racks
where some vibration or occasional wire movement
can be expected. Both cables afford ground control by
permitting the shield to be grounded only at those
Auxiliary
Equipment
Interconnecting Cables
Page A802
Types FA -19 -J, FA -19 -M, and FA -19-R
FA-19 -J
I/64.
POLYVINYL CHLORIDE INSULATION
RED LAOUERED CELANESE
OR RAYON BRAID
TINNED COPPER OVERALL
BRAIDED,SHIELD
PAIR WRAP OR PAPER FOLD
BLACK LAQUERED CELANESE
OR RAYON BRAID
#16
AWG STRANDED TINNED
COPPER CONDUCTOR
points desired. Both are capable of carrying L8
amperes at 400 volts d -c.
The Type FA -19 -J interconnecting cable is a
medium -diameter, two- conductor shielded cable designed for use in power and high -level audio circuits.
Primarily intended for handling power, this cable is
composed of two No. 16 AWG stranded conductors
with heavy insulation and an over -all braided, tinned
copper shield. This cable is recommended for power
use up to 8.0 amperes at 600 volts and for use in high level audio circuits where shielding is desired, as in
ducts, conduit, and cabinets.
SPECIFICATIONS -MECHANICAL AND
ELECTRICAL
TYPE FA -19 -J
Two No. 16 AWG, stranded, tinned copper conductors with
e, -inch, black polyvinyl chloride insulation on each conductor.
One conductor covered with black lacquered celanese or rayon
braid; second conductor covered with red lacquered celanese
or rayon braid. The two conductors are twisted and given a
pair wrap or paper fold, with a tinned copper, braided over -all
shield. Length per spool, 500 feet. Rated voltage: 600 volts
d -c at 8 amperes. Outside diameter: 0.245 inches.
TYPE FA -19M
Two No. 22 AWG, solid, tinned copper conductor with nylon
extruded insulation. One conductor has a black celanese wrap;
second conductor has red celanese wrap. A nylon jacket is extruded over the celanese wrap of each conductor. One No. 22
solid, tinned copper ground wire is twisted with the two identified
conductors and the whole included in a wrapped, tinned copper
shield. A polyvinyl jacket covers over -all. Cable is furnished on
500 -foot spools. Rated voltage: 400 volts d -c at 1.8 amperes.
Outside diameter: 0.152 inches.
TYPE FA -19 -R
Two No. 22 AWG, stranded, tinned copper conductors with
nylon extruded insulation. One conductor covered with black
celanese wrap; second conductor covered with red celanese wrap.
Over the celanese wraps on each conductor is extruded a nylon
jacket. One No. 22, stranded, tinned copper ground wire is
twisted with the two identified conductors and the whole included in a wrapped, tinned copper shield. A polyvinyl jacket
covers over -all. Cable is furnished on 500 -foot spools. Rated
voltage: 400 volts d -c at 1.8 amperes. Outside diameter: 0.52
inches.
RECOMMENDED NUMBER OF CABLES IN ONE CONDUIT
Conduit Size (Nominal)
In Inches
Cable
/a
Type
FA
-19 -J
Type FA- 19 -M...
Type FA- 19 -R..
2
6
6
3.
4
10
10
1
7
17
17
4'%
11/4
11/2
2
21/2
3
3Y2
4
13
17
28
40
62
83
107
135
138
185
238
300
138
185
238
300
28
28
38
38
63
63
88
88
HOW TO ORDER
When ordering, please specify:
Interconnecting cable;
Type No. FA -19
feet;
spools.
Auxiliay
AUDIO
Equipment
Equalizer Panel
Page A803
Type FA -14-A
Equalizer panel, Type FA14 -A
MECHANICAL SPECIFICATIONS
FEATURES
DIMENSIONS
Provides equalization for two lines
Front -panel adjustment in steps of
Depth
Height
3
db
Equalizes short lines up to 15,000 cycles-longer
lines up to 10,000 cycles
4 ¡¿ inches
3,z inches
Width
Weight
19
5
inches
Ib
MOUNTING
The equalizer panel is designed for vertical mounting on a
19 -inch EIA relay or cabinet rack. A clamp -type mounting, not visible from the front, is provided to mount the panel
in any desired location on a rack.
standard
ELECTRICAL SPECIFICATIONS
Simple clamp -type mount permits flexibility of
mounting on any standard rack
WHERE TO USE
The General Electric Type FA -14 -A equalizer panel
the nonlinear characteristics
of one or two nonloaded telephone lines for substantially flat frequency response to 10,000 or 15,000 cycles
per second, depending on line characteristics and termination. The Type FA -14 -A would normally be used
on lines which are not continuously operating and do
not require the permanent installation of a fixed
equalizer.
is designed to equalize
TYPE OF CIRCUIT
The Type FA -14 -A equalizer consists of two separate and
complete Type FA -14 -B equalizers mounted on a single panel.
Parallel- resonant circuits consisting of a capacitor, a reactor,
and logarithmically tapered resistances are used in each equalizer
unit. These resistances are selected by a rotary switch located on
the front panel. Input and output connections of the Type
FA -14 -A are available on terminal boards.
The electrical specifications for each of the sections
of the equalizer panel are the same as the specifications for the equalizer unit, Type FA -14 -B.
HOW TO ORDER
When ordering, please specify:
Type FA -14 -A equalizer panel.
Equalizer panel, Type FA -14 -A, rear view
Auxiliary
AUDIO
Equalizer Unit
Equipment
Page A804
Type FA -14-B
FEATURES
Equalizes up to 10,000 or 15,000 cycles depending
on line length and termination
Easily connected for equalization in steps of
or less
3
db
Small size allows flexibility of mounting
WHERE TO USE
The General Electric Type FA -14 -B equalizer unit
semi -fixed unit recommended for use on lines which
are permanently installed and continuously used, such
as studio -to- transmitter lines and remote or "nemo"
lines. It is designed to equalize nonlinear characteristics
of non -loaded telephone lines for substantially flat
frequency response up to 10,000 or 15,000 cycles -persecond, depending on line characteristics and terminis a
at ions.
Equalizer unit, Type FA -14 -B
INSERTION LOSS (600 -ohm source and load)
(See frequency characteristics curve
R =8 ohms:
41 -db max at 30 cycles,
2.5 -db min at 11,000 cycles
R=180 ohms: 8 -db max at 30 cycles,
7 -db min at 11,000 cycles
MECHANICAL SPECIFICATIONS
DIMENSIONS (Two rock units)
Depth
Height
3
3
inches
ÿ inches
Width 3% inches
(Includes mounting)
Weight 11 = lb
EQUALIZATION RANGE
MOUNTING
10
,
loon
1200
I
.
!.111
.7n
WEI
uuNll1
I
ion
:1Ì!
It
sen
sen
20
ran
TYPE OF CIRCUIT
The Type FA -14 -B equalizer unit consists of a reactor, a
capacitor, and associated resistors mounted in a rectangular
metal case. A solder -lug terminal board is provided on one end
of this case for adjusting the resistance and for connecting the
unit to the line.
O
w
30
40
//
600 or 150 ohms
EQUALIZATION ABILITY (dependent on line length)
Line termination 150 ohms: 30 to 15,000 cps
Line termination 600 ohms: 30 to 10,000 cps
30
%'
40
o
20
to
180
20
I
.
FREO (CYCLES PER
1
UNE IMPEDANCE
t
NMIE
2711
I
mo
o
r0
II
I
Mounting flanges on the bottom of the case make it adaptable
for mounting on any flat surface.
ELECTRICAL SPECIFICATIONS
1
Refer to frequency characteristics curve.
100
SECOND),
1000
10000 20000
Frequency characteristics, 600 -ohm source and load
HOW TO ORDER
When ordering, please specify:
Type FA -14 -B equalizer unit.
Auxiliary
AUDIO
Equipment
Program Level Indicator Panel, Type FA -1 -A
Page A805
Switch and Fuse Panel, Type FA -4 -A
Program level indicator panel, Type FA -1 -A
FEATURES
Measures levels from 4 -4 to } -42 VU
May be switched to any of ten program lines
Uses large size, illuminated standard VU meter
Clamp -type mounting for easy installation
WHERE TO USE
The General Electric Type FA -1 -A program level
indicator panel provides a means of measuring accurately the program level of up to ten 600 -ohm audio
lines. The level of lines having other impedances may
be measured by applying suitable correction factors.
Program -level readings obtained with this unit are in
"volume units" (VU). When used to make steady state, single- frequency measurements, the readings
obtained are in dbm.
FEATURES
Easy access to fuse block through hinged -front
panel
Unused surface on removable back plate readily
fitted with additional equipment
Attractively styled for any cabinet mounting
WHERE TO USE
The General Electric Type FA -4 -A switch and fuse
panel provides a master -power switch, indicator lamp,
and fuse protection for an entire cabinet or relay rack.
DESCRIPTION
DESCRIPTION
The unit includes a two -circuit, ten -point selector
switch (plus an OFF position), a variable step -type
attenuator which provides readings of from +4 to
+42 VU (or dbm) in 2 -db steps, a VU meter, and a
calibrating potentiometer for making a fine adjustment of the level reading over a range of
, dbm.
The illuminated VU meter has two scales: the upper
scale is calibrated in percent, ranging from 0 to 100;
the lower scale is calibrated in VU, ranging from 20
to +3. A source of 6.3 volts at 0.3 -amp is required for
illumination.
t
1
-
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth
Height
Width
Weight
Switch and fuse panel, Type FA -4 -A (front panel open)
inches
inches (3 RU
inches
4! ; lb
333;
5372
19
MECHANICAL SPECIFICATIONS
MOUNTING
The unit mounts on a standard 19 -inch RETMA relay or
cabinet rack. A clamp -type mounting, which is not visible from
the front, is provided to mount the panel in any desired location
on the rack.
VU SCALE
"B" Scale
ELECTRICAL SPECIFICATIONS
Input impedance
7500 ohms
Measurement range
+4 to +42 VU (or dbm)
(600 -ohm lines)
Number of lines that
may be measured
Power circuits running through the Type FA -4 -A
switch and fuse panel are activated by the switch. Dual
fuses protect equipment from surges and shorts in the
power line. The panel light indicates that the line is in
use, or, with switch on and light out, indicates circuit
trouble. The hinged -front panel allows easy access to
the fuse block on the inside back plate for inspection
or replacement of fuses. Two fuses of the screw -plug
type are required, but are not furnished since their
rating depends upon the load to be protected. On
the removable back plate are approximately 100
square inches of unused surface which may be used to
mount additional terminal distribution blocks, filament or line transformers, line pads, equalizers, relays,
and other appropriate components. A % -inch diameter hole is provided at each end of the chassis for
connecting external wires.
DIMENSIONS
Depth ibehind panel,
(over-all)
Height
Width
Weight
to 10, inclusive
HOW TO ORDER
51:_;
lb
ELECTRICAL SPECIFICATIONS
Switch
Fuses (not furnished)
in 2 -db steps
1
3!4 inches
4 ¡fi inches
oil inches (4 RU
19
inches
Lamp
DPST, 20 -amp, 125 -volt
Plug type; rating dependent on
equipment to be protected; 20amp maximum
Mazda No. 6S6, 120 -volt, at 6 watts
HOW TO ORDER
When ordering, please specify:
Type FA -1 -A program level indicator panel.
When ordering, please specify:
Type FA -4 -A switch and fuse panel.
www.americanradiohistory.com
AUDIO
Auxiliary
Sound Effects Filter Panel
Equipment
Page A806
Type FA -18 -A
Sound effects
filter panel, Type FA -18 -A
FEATURES
Simple control of desired bandwidth
Gives variety of "bassy" or "tinny" effects
Telephone conversation effect may be created
Helps to eliminate static from overseas or shortwave pickups and rebroadcasts. Clarifies speech
intelligence
Easy installation and operation
Telephone -type key permits instant switching in or
out of audio circuit
WHERE TO USE
The General Electric Type FA -18 -A sound effects
filter panel provides control of program bandwidth,
enabling the user to obtain unusual dramatic sound
effects. Speech and music may be made "bassy" or
"tinny" and "telephone- quality" effects may be
simulated.
DESCRIPTION
The Type FA -18 -A sound effects filter panel consists of adjustable high- and low -pass filter sections
mounted on a panel. Each of the filters are connected
to a variable cutoff frequency- selector switch con-
trolled by a front -panel knob. Each switch has eight
cutoff positions (100, 250, 1000, 2000, 3000, 4000, and
5000 cycles) and an OFF position. A key switch is
provided to connect or disconnect the filter circuit so
that the filter may be preset at any time for desired
characteristics and inserted in the circuit when required.
MECHANICAL SPECIFICATIONS
DIMENSIONS
Depth (including front panel control)
Height
8
5:¡:.
inches
inches (three rack
Width
Weight
19
9 lb
inches
MOUNTING
The sound effects filter panel is designed for vertical mounting
on a standard 19 -inch relay or cabinet rack. A clamp -type mounting, not visible from the front, is provided to mount the panel in
any desired location on a rack.
ELECTRICAL SPECIFICATIONS
Source Impedance:
Operating Level:
Load Impedance:
Insertion Loss:
IIIIIÌÍ:Ì%i/r
1\I;lll
1
.
11111111
12
11,
I
12
600 ohms (unbalanced)
40 to +20 dbm
600 ohms (unbalanced)
1 db or less at passed frequencies
HOW TO ORDER
When ordering, please specify:
Type FA -18 A sound effects filter panel.
iiiiliimiliiüiiibli1111
11111i1
units)
,
-
I
16
(
20
ö
s
0
.
1.14D
600
NSf31
-70
-24
f
8
I
S2
I4
I
I
ÿ'1
S1
i
4
E
loo
I
Typical attenuation
IIOUINCI
IN
¡
21
-1
100
1.140
I
=Qç.
Ó
1
S'S I
1IR i
1Lÿ¿
4
72
.,....
10000
Ì
GYMS 1II SICONO
IIE0UINC1
characteristics of high- frequency cut -off
section of sound effects filter panel, Type FA -18 -A
1
!
I
1000
CO
22000
a.00
i
MK'
I1S1E1
OMMS
;
C1.4
C1C
1
li!I!I
10200
20000
IN CYCNS 131 SECOND
Typical attenuation characteristics of low -frequency cut -off
section of sound effects filter panel, Type FA -18 -A
www.americanradiohistory.com
Auxiliary
AUDIO
Equipment
Jack Strip
Page A807
Type FA -2 -A
..
1-
aj
',
Jack strip showing common ground, Type FA -2 -A
FEATURES
Easily wired ground terminals
The jacks used on these jack strip assemblies are pro-
vided with special off -set sleeve (or grounding)
terminals, designed so that the sleeve terminals fall in
down the center of the assembly when two rows of
jacks are mounted on the strip. This makes it possible to
ground all sleeves by simply passing a single straight
length of bus wire through all sleeve terminals. Results
are savings in labor, time, and wiring space.
a line
Jack strip, Type FA -2 -A
Textolite* board. All jacks are of the tip and sleeve
type with an additional normally closed contact making the jack suitable for use on "normalled through"
circuits.
Jacks are mounted on 5 -inch horizontal centers so
as to mate properly with General Electric patch cords
(Types FA -7 -A, B 86 C) and other manufacturers'
standard, double -plug patch cords.
Increased strength
The two -sided construction of this jack adds
rigidity,
reducing the possibility of wire breakage, and makes
smoother operating jack -strip assembly.
a
Easily mounted
The vertically slotted end -mounting brackets permit
some vertical movement of the jack strip. This facilitates
the mounting of the strip when used in conjunction with
odd sized rack -mounted equipment.
The Type PV -14 -A card holder kit
The card holder kit is available for labeling of the jack
strips where the strips are to be mounted within the
rack instead of front flush mount.
WHERE TO USE
The General Electric Type FA -2 -A jack strips are
used in amplifier racks to permit rapid isolation, selec-
tion, and monitoring of individual amplifiers by means
of patch cords. They are also used in studio- and master
control room consoles and racks to permit "patching"
of the various remote, local, and audition programs
into the desired transmitter, remote, and monitoring
channels.
-
DESCRIPTION
The General Electric Type FA -2 -A jack strip consists of 48 jacks, mounted in two rows on heavy black
MECHANICAL SPECIFICATIONS
DIMENSIONS
Height
Width
Depth
Weight
21/1 inches
18;4 inches
358 inches approx
V., lb
MOUNTING
Mounting brackets at the end of the strip are vertically
slotted to fit a standard 19 -inch EIA cabinet or relay rack. Two
No. 12 24 screws are supplied to mount each jack strip. Jack
panels, Type FA -3 -A, -B, and -C, may be used with the Type
FA 2 -A to provide designation cards above and below each jack
ELECTRICAL SPECIFICATIONS
Number of jack pairs
Type of jack
2l
Tip and sleeve
through contact
with
normalled-
HOW TO ORDER
When ordering, please specify:
Type FA -2 -A jack strip.
ACCESSORIES
Type PV- 4-A card holder kit
Type FA -7 -A B C 2 -, 4 -, or 6 -foot patch cords
Type FA -3 -A B C single, double or triple jack
panels
* Registered trade -mark of General Electric Company.
www.americanradiohistory.com
Auxiliary
AUDIO
Equipment
Jack Panels
Page A808
Types FA -3 -A, FA -3 -B, and FA -3 -C
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Patch Cords
Types FA -7 -A, FA -7 -B, and FA -7 -C
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B
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From top, jack panels, Types FA -3 -A, FA -3 -B and FA -3 -C
Patch cords, Types FA -7 -A, -B and -C
DESCRIPTION
DESCRIPTION
Jack panels are available for covering one, two or
three General Electric Type FA -2 -A jack strips.
Designation cards inserted behind clear plastic
strips are mounted in card holders on each panel above
and below each pair of jack openings.
SPECIFICATIONS
Type No
FA-3-A
FA-3-8
FA-3-C
Weight
Description
Height (In Inches)
Single jack panel..
Double jack panel.
Triple jack panel
3.,
1i.
53'.2
l
bix
2
]1
General Electric patch cords consist of two insulated
copper conductors shielded with tinned copper braid
and covered with heavy black cotton braid. A six -inch
length at either end is reinforced so that the two -conductor double plug may be securely mounted. The
plug at either end is interchangeable with the W.E.
Type 241 -A double plug. The shield of the cord is
connected to the sleeves of both plugs.
(In Lb)
SPECIFICATIONS
General Electric patch cords are available in three sizes:
Cord Length
Type No.
2 feet
FA -7 -A
FA -7 -B
4 feet
FA -7 -C
6 feet
'/a
MOUNTING
A mounting is furnished with each panel to secure it to the
ack strip so that no mounting screws will be exposed.
HOW TO ORDER
When ordering, please specify:
Type FA -7- .. patch cord.
HOW TO ORDER
When ordering, please specify:
Type FA -3 -.. jack panel.
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4,4
Use
`..±.÷:±±±ii
of jack panel provides
a
neat flush mounting of jack strips in
www.americanradiohistory.com
a
rack
WILLIAM G. BROUGHTON
General Electric Co.
1
River Road
Bldg. 33, Room 204
Schenectady, New York
THOMAS F. BOST, JR.
1330 W. Peachtree St., N. W.
Room 517
Atlanta, Georgia
HUGH W. GRANBERRY
General Electric Co.
565 Broadway
Trinity
Emerson 8 -4681
5 -6691
Redwood City, California
Express 3-9110
LEWIS F. PAGE
General Electric Co.
420 Lexington Avenue
Room 2129
New York, New York
Plaza
1
ROBERT W. COCHRAN
General Electric Co.
Suite 210
232 North Lake Avenue
Pasadena, California
VERNON H. RUSSELL
General Electric Co.
478 N. W. Highway
Des Plaines, Illinois
Cypress 9 -3369
Murray -5965
1
-1311
E. LAUTERBACH
General Electric Co.
Bldg. 27
3628 W. 95th Street
Shawnee Mission Kansas
ROBERT
EARL H. PLATT
General Electric Co.
1013 Williamson Bldg.
Cleveland, Ohio
JOHN F. WATTER
General Electric Co.
777 14th St., N. W.
927 Wyatt Bldg.
Washington, D. C.
Mitchell 9 -7131
Executive
Atlanta, Georgia
JAMES H. DOUGLAS
General Electric Co.
4447 N. Central Expressway
Room 400
Dallas, Texas
HAROLD H. CONDO
General Electric Co.
Division Street Plant
Room 11 -3rd Floor
Syracuse, New York
Trinity 5 -6691
Lakeside 6-0426
Granite 6-4411 -Ext. 6305
Superior 1 -6822
JAMES M. COMER, JR.
1330 W. Peachtree St., N. W.
Room 517
3 -3600
Canada: Canadian General Electric Co., Ltd., Broadcast Equipment Sales, 830
Lansdowne Ave., Toronto, Ontario. Outside the'U.S.A. and Canada: International
General Electric Co., Inc., 150 E. 42nd St., New York, N. Y.
In
GENERAL
ELECTRIC
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