FSM-400 - Formula Sound

FSM-400 - Formula Sound
FSM 400
MIXER
USERS MANUAL
FSM-400 INTRODUCTION
The FSM-400 is a compact fixed format stereo production mixer. The design allows
the unit to accept one microphone input and seven stereo music inputs.
The FSM-400 is essentially a four channel mixer with each channel switchable to
two inputs. Channel 1 is switchable between low impedance microphone and a
stereo line input. Phantom power is available for microphones (internal selection).
Channels 2 to 4 are switchable between A and B stereo line inputs. The A input
may be internally selected to RIAA or normal line. These channels are fully
assignable to the crossfader. Three band equalisation is fitted to all channels with
a range of +5dB to -20dB. The large amount of cut eliminates the need for
frequency cut switches. A gain control is also fitted to all channels. Channels 2 to 4
have internal jumpers to provide 2 gain settings per input, the gain range is:normal +/- 15dB or low setting +2dB to -19dB. Illuminated push button switches
are used for input selection, PFL (pre fade listen), routing, etc. A smooth 60mm
fader, which is arranged to eliminate the ingress of dirt, complete the channel
controls.
The output section provides plenty of facilities to cope with most applications. It
includes a new design of crossfade circuitry that places less demand on the fader
to ensure exemplary attenuation and extended life. A punch button facility is also
included.
Unlike the majority of fixed format mixers on the market all connectors are fitted to
the back face which allows unrestricted access when the mixer is fitted through a
work top or console.
Although the FSM-400 is a fixed format design the use of individual circuit cards per
channel improve reliability and aid servicing should the need arise. Construction
and audio quality are to Formula Sound’s usual highest standards.
Power
The mixer features a fully regulated internal power supply that is designed to
operate on 220-240Vac or 110-120Vac. The selection is by an internal switch
mounted on the power supply circuit board and is accessed by removing the front
cover.
DAMAGE MAY RESULT IF THE UNIT IS CONNECTED TO THE WRONG
SUPPLY VOLTAGE
Fuses
Mains fuse sizes are 315mA anti surge for 220-240V operation and 800mA anti
surge for 110-120V operation. It is important for safety reasons that the correct
fuse sizes are always used.
N.B. Internal settings should only be undertaken by skilled
personnel
Always remove the power cord before removing any covers.
Page 1
1M
1L
GAIN
INPUT CHANNEL 1
Input selector switch selects input used. M =
microphone (XLR connector). L = stereo line (phono
connectors). 2 parallel pairs of phono sockets allow
easy parallel of source to a second input if required.
L.e.d.s and label area clearly show which input is in
use.
Gain control sets input gain level. Check by selecting
PFL and adjusting so that V.U. meter just peaks into
red.
TREBLE
3 band equalisation provides +5dB -20dB control.
MID
BASS
MUTE
E.Q. OUT
PFL
Mute push button cuts the channel signal when
depressed (switch illuminated).
E.Q. OUT
This push button bypasses the equaliser section.
This is a useful function to either switch e.q. in or out
for effect or for bypassing mic e.q. when using the line
input.
PFL (pre-fade listen) routes the channel signal to the
monitoring system (V.U. meter and phones). If more
than 1 PFL is selected the sum is routed to the
monitoring system. If no PFL is selected the
monitoring system reads main output.
60mm channel fader.
Note
For normal microphone operation the fader should not
be holding much gain. Set the fader to No. 7 and
adjust the gain for normal volume. If the fader is below
No. 7 during normal operation turn down the gain
control and turn up the fader. This gives the best
performance.
Page 2
GAIN
TREBLE
MID
BASS
XF A
XF B
2A
INPUT CHANNELS 2 TO 4
2B
Input selector switch selects input used. A = input A
B = input B. Input B is always a stereo line input
(internal jumpers selects input A to be either RIAA
magnetic cartridge or a standard line input. (phono
connectors)).
L.e.d.s and label area clearly show which input is in
use.
Gain control sets the input gain level. Check by
selecting PFL and adjusting so that V.U. meter just
peaks into the red.
3 band equalisation provides +5dB -20dB control.
XF A and XF B (Illuminated push buttons) assign the
channel to the crossfader. If neither button is
pressed the channel is fed via the stereo buss to the
output and the crossfader will have no effect on this
channel. If both buttons are pressed the channel will
be assigned to A only
PFL
PFL (pre-fade listen) routes the channel signal to the
monitoring system (V.U. meter and phones). If more
than 1 PFL is selected the sum is routed to the
monitoring system. If no PFL is selected the
monitoring system reads main output.
60mm channel fader.
Note
For normal operation the fader would normally be
used at maximum and the gain control adjusted for
normal volume. If the fader is set below No. 7 during
normal operation turn down the gain control and turn
up the fader. This gives the best performance.
Page 3
Output Section
POWER
MAIN OUTPUT / PFL
-20
-10
-7
-5
-3
MUSIC MUTE
ZONE
-1
0
+1
+2
+3
+6
PFL SELECTED
BOOTH
ATTENUATION
PHONES
TALK OVER
SPLIT
MASTER
STEREO
JACK
FSM-400
PUNCH
FORMULA SOUND
Power switch switches the
mains feed to the mixer
power supply. N.B. to
avoid switch on thrumps
audio systems need
powering up in sequence.
A good rule to remember
is - power amps on last
and off first.
MONITORING
Twin l.e.d. bargraph V.U.
meters show the main
output signal or PFL
signals. The changeover
is by selecting PFL on any
channel. Any number of
PFL sources may be
selected and the sum of
these will be monitored.
This provides a very
versatile monitoring
facility. Depressing the
SPLIT button allows both
main output and PFL
signals to be monitored
simultaneously. This
function is often preferred
when mixing tracks in
synchronisation. The two
signals are summed to
mono and presented to
the monitor section with
the main output fed to left
and PFL fed to right
sections. The phones
output always follows the
metering so what you see
is what you hear.
As an extra aid an
adjacent l.e.d. illuminates
to indicate when any PFL
source is selected.
Page 4
BOOTH - controls the booth output level. This output may be used to provide a
local monitor output. To eliminate any possibility of feedback no microphones are
fed to this output. Stereo or mono outputs are available via the 0.25” jacks on the
rear panel.
PHONES - the master volume control for the headphone monitoring system. Two
stereo jacks are provided, one on the front panel and one on the rear. STEREO
jacks must be used - a mono two circuit jack will present a short to one half of the
phones amplifier and although current limiting protection is included, prolonged use
should be avoided. The phones amplifier is very powerful and capable of delivering
over 1 Watt per channel into the optimum load of 30 ohms.
MASTER - controls the level of the main output and features balanced outputs on
XLR connectors as well as a separate mono output on a 0.25” jack.
CROSSFADE - A 45mm fader is featured that can be used to smoothly fade
between the XF-A buss and XF-B buss. To improve crossfader life and also ensure
good attenuation at the ends of travel, studio quality VCA circuits have been used.
The use of VCA’s over conventional faders give superior crossfade performance.
PUNCH - A momentary action push button is fitted, which when pressed, switches
both XF-A and XF-B signals on. Wherever the crossfader is set pressing the punch
button will always add the opposite side. The Punch circuit action is click free, and
provides the creative operator with a useful facility.
ZONE - controls a further output similar to the master output but without the
balanced output driver. Stereo or mono outputs are available via the 0.25” jacks on
the rear panel.
TALK OVER - circuitry is included that is selected via an illuminated push button.
The action of this circuit is to attenuate the music when the switch is pressed. The
attenuation level of the music is variable - turning the pot clockwise turns up the
music.
RECORD OUTPUTS - Two sets of stereo record outputs are available via phono
connectors. One is a complete programme mix, the other is music sources only
(similar to the booth output). All record outputs are unaffected by the master
controls.
SUB BASS OUTPUT - a mono output via 0.25” jack is provided for driving a sub
bass loudspeaker system to enhance low frequency performance. The filter allows
frequencies below 70Hz to pass through. An internal jumper allows higher bass
output if required.
SOUND TO LIGHT (TRIG) - a fully floating transformer isolated trigger output is
available on a 0.25” jack to provide safe connection to lighting equipment.
REMOTE MUSIC MUTE - To cater for the increasing requirement to mute music
signals in entertainment venues when the fire alarm is activated the FSM-400 has
provision to remotely mute all music sources by linking two pins on the connector
provided. The fire alarm panel needs to provide a fully floating pair of contacts
which close when the alarm is activated. An l.e.d. positioned below the V.U. meter
clearly shows if the music mute is activated
Page 5
Service and Configuration
Several internal options are available on the FSM-400. These should only be
undertaken by qualified personnel.
Always remove the power cord before removing covers.
To gain access to the internal parts of the FSM-400 remove 4 screws from each of
the two side covers which surround the FSM-400. This will give access to the
internal jumpers and adjustments.
Channel options (remove top cover).
Channel 1. One jumper fitted towards the top of the channel pcb provides
microphone phantom power selection. Pcb notation shows positions.
Channels 2-4 - N.B 2 jumpers per channel must be moved
4 jumpers located behind the input selector switch provide selection for input A and
B to be set to low gain. They are labelled AR (chan A right) BR (chan B right) AL &
BL etc. The low gain setting is with the jumper positioned away from the switch.
Ensure that the correct jumpers are moved and they are correctly located on the
pins.
Removing all the jumpers will set inputs A and B to the low gain settings.
2 jumpers provide selection for the A input to be a flat line input or an RIAA
magnetic cartridge input. Pcb notation shows the position for the jumpers. Ensure
that both jumpers are moved to the correct positions and located correctly on
the pins.
MAINS VOLTAGE SELECTION - The FSM-400 can be switched to operate on
220-240Vac or 110-120Vac. The selection is by a slide switch mounted on the
power supply pcb at the mains transformer end. Notation on the pcb and switch
clearly show the switch position. If you need to change the mains operating voltage
you will also need to change the main fuse. The fuse is located in a slide out drawer
which is part of the mains connector. The connector is mounted on the mixer rear
panel.
Fuse sizes 220-240v operation = 315mA anti surge 5 X 20mm fuse
110-120V operation = 800mA anti surge 5 X 20mm fuse
Removing the top cover also exposes the right end output pcb. The sub bass
adjustment is located on this board - and is controlled by 1 jumper located above
the sub bass jack socket. Adjacent notation shows the positions.
Fader Replacement
Should fader replacement become necessary any of the faders can be replaced by
removing the bottom side cover. Remove the 2 screws securing the fader and
disconnect the connector. Replace with a new fader assembly.
Page 6
Mixer Dimensions
Width
Height
382mm (15”)
Rack mount version
283mm (11.125” ) Rack mount version
Depth
110mm (4.33”)
483mm (19”)
312mm ( 12.25”) 7RU
Installation cut out for mounting the FSM-400 through a work surface.
330mm wide X 270mm height
Formula Sound Ltd
Unit 23; Stadium Business Centre
North End Road
Wembley
Middlesex
England
HA9 0AT Tel +44 (0)208 900 0947 Fax +44 (0)208 903 8657
www.formula-sound.co.uk
Email: [email protected]
Page 7
INSTALLATION, CONNECTIONS AND GOOD WIRING PRACTICE
The installation of professional audio systems should be left to experienced
engineers wherever possible. The interconnection of audio systems can be fairly
complex depending on the type and size of system and obviously well outside the
scope of this handbook. We have included a few basic points for information for
anyone who is new to audio systems.
Good wiring practice should be observed when connecting any audio equipment.
Good quality connectors and screened cable should be used for all audio
connections .
Twin screened cable should be used for all balanced lines particularly microphone
connections.
Always ensure cable clamps in connectors are fully tightened and gripping the outer
sheath. Good strain relief and mechanically sound connections will increase
reliability at virtually no extra cost.
GROUND LOOPS
In our experience this is the most common problem encountered when connecting
together different items of audio equipment. It is the most common cause of hum
(50Hz noise) on a system and is caused by incorrect system grounding.
When several items of audio equipment are connected together with unbalanced
connections (i.e. 2 connections, single screened cable, etc.) the signal common
connection is the screen and this will be connected to mains earth at some point. If
several items of equipment have their signal common connected to mains earth this
will form a loop (hence ground loop). Current will flow in this loop and appear in the
form of hum (50Hz mains frequency) added to the audio signal. The problem is
aggravated if the equipment is located a distance apart as the loop is larger. It is
possible to have several ground loops within a system. The solution is to connect
the system to mains ground only once. This is usually done at the mixer. You will
need to investigate the various items of equipment you are using and isolate their
signal common from mains earth. Many manufacturers fit a ground lift switch for
this purpose. On some equipment this is in the form of a removable link.
Unfortunately with some equipment you have to get inside to identify where the
connection is and remove it.
YOU MUST NOT DISCONNECT THE MAINS EARTH WIRE
FROM THE MAINS PLUG OF ANY EQUIPMENT. THIS IS
FITTED FOR SAFETY REASONS AND MUST BE
CONNECTED TO ENSURE THE CASE IS EARTHED.
Page 8
FORMULA SOUND LIMITED
UNIT 23; STADIUM BUSINESS CENTRE; NORTH END ROAD; WEMBLEY; MIDDLESEX; HA9 0AT
TELEPHONE +44 (0)208-900-0947 FAX +44 (0)208-903-8657
www.formula-sound.co.uk email [email protected]
E.U. CERTIFICATE OF CONFORMITY
We declare that the products listed conform to the following directives and standards
89/336/EEC amended by 92/31/EEC and 93/68/EEC
BS EN 50082-1 BS EN 50081-1
PRODUCT TYPE
FSM 400
The CE mark was first applied in 1995
Signed
B. J. Penaligon General Manager
Attention
The attention of the specifier, purchaser, installer, or user is drawn to the fact that
good wiring practice must be observed when connecting the above equipment. Good
quality connectors and screened cables must be used for all audio connections. Twin
screened cables should be used for all balanced lines.
THIS EQUIPMENT MUST BE EARTHED
CONSULT THE USERS MANUAL FOR TECHNICAL DETAILS
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