Supersonic FSM-600 User manual

FSM-600 INTRODUCTION
The FSM-600 is a compact fixed format stereo production mixer. The design allows
the unit to accept two microphone inputs and ten stereo music inputs.
The FSM-600 is essentially a six channel mixer with each channel switchable to two
inputs. Channels 1 and 2 are switchable between low impedance microphone and
stereo line inputs. Channels 3 to 6 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 cross fader. Three band equalisation is fitted to all inputs along
with gain and auxiliary send controls. Illuminated push buttons and a 60 mm fader
complete the channel controls. Internal settings provide for the unit to be set to
individual needs. The output section provides plenty of facilities to cope with the most
demanding applications.
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 in a rack.
Although the FSM-600 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.
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Page 2
INPUT CHANNELS 1 AND 2
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.
3 band equalisation provides +/- 10dB control, internal jumpers allow
selection of +/- 5dB or no E.Q.
Auxiliary send allows a separate mix of channels to auxiliary output (stereo
bus). Internal jumpers allow the auxiliary pot to function pre or post channel
fader.
Mute push button cuts the channel signal when depressed (switch
illuminated). It does not cut the auxiliary send.
Limit push button routes the microphone signal via a built in
compressor/limiter to keep dynamics under control. An internal jumper
disables the switch forcing the mic to always be routed to the limiter. This
switch has no effect on 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.

INPUT CHANNELS 3 TO 6
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 +/- 10dB control, internal jumpers
allow selection of +/- 5dB or no E.Q.
Auxiliary send allows a separate mix of channels summed to the
auxiliary output (stereo bus). Internal jumpers allow the auxiliary pot
to function pre or post channel fader.
XF A and XF B (Illuminated push buttons) assign the channel to the
cross fader if neither button is pressed the channel is fed via the
stereo buss to the output and the cross fader will have no effect on
this channel if both buttons are pressed the channel will be assigned
to A only
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

FORMULA SOUND
CROSS FADE
PUNCH
A
MASTER
ON
FSM-600
B
JACK
STEREO
SPLIT
MAIN OUTPUT / PFL
R
AUTO VOICE OVER
ATTENUATION
SENSITIVITY
MUSIC MUTE
-20
L
-10
ZONE
LIMITER
-7 -5
MIC
-3 -1
12V LAMP
dB
PHONES
BOOTH
AUX
PFL SELECTED
0+1 +2 +3
dB
+6
POWER
As an extra aid an adjacent l.e.d. illuminates to indicate when any PFL source is selected.
A microphone limiter circuit is fitted to the FSM-600 to keep dynamics under control. If any
microphone is routed via this limiter a yellow l.e.d. positioned below theV.U. meter will show
when the limiter threshold is exceeded. The factory setting for the limiter threshold allows an
output level of +2dBm. An internal trimmer provides different settings of the threshold if
required.
Page 4
Output Section
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.
The BNC connector will provide
12V at a maximum 500mA for
working illumination. A suitable
light on a flexible stem is
available, ask our sales office for
details.
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 andPFL
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.

AUX - controls the summed output level of the individual channel auxiliary send controls.
Stereo or mono outputs are available via the 0.25” jacks on the rear panel.
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 andXF-B buss. To improve cross fader 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 X-FB signals on. Wherever thecrossfader 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.
AUTO VOICE OVER - circuitry is included that is selected via an illuminated push button .
The action of this circuit is to attenuate the music when a microphone signal is present. The
attenuation level of the music is variable, turning the pot clockwise turns up the music. The
sensitivity pot adjusts the point where theAVO circuit is triggered. Adjust the sensitivity
control so that the circuit triggers on normal speech but not on background pick up.
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.
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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-600 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 theV.U. meter clearly shows if the music mute is
activated.
Service and Configuration
Several internal options are available on the FSM-600. 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-600 remove 4 screws from each of the two
side covers which surround the FSM-600. This will give access to the majority of the internal
jumpers and adjustments. The only exception to this is the jumpers which set the channel
E.Q. range and AUXILIARY pre or post. To gain access to these jumpers the back panel
also has to be removed. ( See removing back panel).
Channel options (remove top cover).
Channel 1 & 2 - 1 jumper fitted towards the top of the channel pcb provides microphone
phantom power selection. Pcb notation shows positions.
Channels 3-6 - 2 jumpers fitted towards top of pcb provide selection for input A to be a flat
line input or an RIAA magnetic cartridge input. Pcb notation shows the position for the
jumpers. Also each of these channels has an internal gain trim pot located above the input
setting jumpers. This pot allows the maximum gain to be reduced. Adjust as necessary.
E.Q. Range Select - This function is set by the position of 4 jumpers - notation on thepcb
show the positions. Take care to locate the jumpers in the correct positions.
AUXILIARY SEND - two jumpers set the selection of pre or post fader - notation on thepcb
show the positions. Take care to locate the jumpers in the correct positions.
MAINS VOLTAGE SELECTION - The FSM-600 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 thepcb 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
Page 6

Removing The Back Panel
To remove the back panel first remove the side covers. Now remove the centre screw on
each block of phono connectors. Remove the jack socket retaining nuts. Remove the four
corner panel retaining screws and the panel will now lift away but will be captive by the
connections to the power supply and mains connector You may at this point be able to make
the adjustments you require. If not the power supply may be removed from the back panel by
removing 3 more screws. Ensure that the power supply is supported and no strain is put on
the connectors or wiring.
Refit in the reverse order taking care to line up all the connectors in the holes and making
sure that no strain is put on the connectors. Ensure that all screws are fitted and tightened.
Removing the top cover also exposes the right end output pcb. Two adjustments are located
on this board - the microphone limiter thresholdpreset and the sub bass output level. The
latter 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 thefaders can be replaced by
removing the bottom side cover. Remove the 2 screws securing the fader. If the connector
is obstructed by the power supply remove the 3 screws securing the power supply. Carefully
disconnect the fader connector and replace with the new fader assembly. Assemble in
reverse order.
Mixer Dimensions
Width 483mm (19”)
Height 312mm (12.25” 7 RU)
Depth 110mm (4.33”)
Installation cut out for mounting the FSM-600 through a work surface.
440mm wide X 305mm height
Formula Sound Ltd
Ashton Road
Bredbury
Stockport
Cheshire
England
SK6 2SR Tel [phone] Fax [phone]
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.