DDA forum-foh Schematic
Forum FOH
Schematics
Klark Teknik Building
Walter Nash Road
Kidderminster
Worcestershire
DY11 7HJ
Tel: +44 (0) 1562 741515
Fax: +44 (0) 1562 745371
Email: info@uk.telex.com
Website: www.ddaconsoles.com
Forum FOH Schematics
Telex Communications (UK) Limited
In line with the company’s policy of continual improvement, specifications and function maybe subject
to change without notice. This Operator Manual was correct at the time of writing. E&OE.
Date: July 11, 1994 Sheet 1 of 1
Size Document Number REV
D CD1209-1 A
Title
FORUM STANDARD INPUT
TEL:(0)81-570-7161 FAX:(0)81-577-3677
DDA LTD., HOUNSLOW, MIDDX., TW3 2EB, ENGLAND
EQ
R35
47K
R36
75R
C17
33P
R33
1K2
C20
100/16
SW4
SW SPDT
R28
10K
R29
10K
R34
47K
C15
15N
C18
470N
R32
1K2
12
13
14
IC2D
TL074
4
5
6
VR6B
100KC
1
2
3
VR6A
100KC
10
9
8
IC2C
TL074
VR7
10KA
C19
470N
C16
33P
R20
1K5
R21
1K5
R22
47K
R23
47K
R24
10K
R25
10K
C10
3N3
C13
2N2
5
6
7
IC2B
TL074
VR2
10KB
3
2
1
4
1
1
IC2A
TL074
1
2
3
VR4A
100KC
4
5
6
VR4B
100KC
C11
33P
HIGH PASS
R16
15K
R17
30K
R19
10K
C8
100N
C9
100/16
R18
75R
5
6
7
IC3B
TL072
SW3
C7
100N
R13
10K
C5
33P
R15
10K
PHASE
C6
100/16
SW2
R102
10K
R9
1K5
R8
1K5
R14
75R
R103
220K
R12
10K
3
2
1
8
4
IC1A
TL072
1
2
3
VR1A
5K RD
C48
100/16
R7
10K
C4
10P
MIC/LINE
R4
7K5
R5
10K
R6
10K
C2
33P
C3
100/16
5
6
7
IC1B
TL072
SW1
TIP
RING
LINE
R1
15K
R2
15K
R3
7K5
C1
33P
2
1
3
4
5
JS1
1/4JACK
IN+
+48V
IN-
XLR2
R87
6K8 1%
R88
6K8 1%
R89
470
R90
1K5
C44
2.2/63
SW6
SUJ2
+48V
R92
10K
C36
47/63
D1
12V
R11
75R
LK1
V+
C39
22/25 C41
1000U
R104
22R
R10
330R
R96
10R
R97
10R
4
5
6
VR1B
5K RD
3
2
1
8
4
IC3A
TL072
R146
100K
R145
100K
R112
150K
R26
3K3
R27
3K3
C12
4N7
R149
100K
R148
100K
R147
100K
V+
R107
100K
D9
18V
Q5
BC550
R30
3K3
R31
3K3
C14
33N
-13
TO SOLO LED
VR3
10KB
VR5
10KB
D10
GRN
R37
10K
GRP 1
GRP 2
R55
10K
R56
10K
+17
+10
0
-7
V-
D14
RED
D13
GRN
D12
GRN
D11
GRN
R54
10K
SW8
SW9
V-LED
V-
V-
C46
2U2
63V
C47
22U
25V
R109
100K
R108
100K
R105
100K
R106
100K
Q4
BC550
Q3
BC550
Q2
BC550
Q1
BC550
V-V-
C45
2U2
63V
R114
47K
1 2 3 4 6 9
57
8
IC7
BA6144
R113
9K1
V-
R98
10K
C38
220P
C40
22/25
C42
100/16
R95
10R
3
2
6
5
1
8
7
4
IC4
SSM2017
R93
10K
R94
24K
C37
47/63
D2
12V
D3
12V
D4
12V
T1
NTM1
LK2
R100
2K2
(OPT)
IN-
-20dB
MIC
XLR3
R91
1K5
C43
10N
R99
10R
R101
330R
SW5
SCREEN
-17V
R116
30K
Q6
BC560
R115
62R
+17V+17V
D8
1N4148
D7
1N4148
V+
C21
220N
5
6
7
IC5B
NE5532
R41
75
C23
220
R45
43R
R44
22K
R42
10K
1
2
3
VR8A
10K
R48
4K7
R49
3K3
R50
100K
R52
3K3
C24
33P
C25
100/16
3
2
1
8
4
IC6A
TL072
R57
10K
R58
10K
R59
10K
R60
10K
R61
10K
SW10
SW11
GRP 3
GRP 4
GRP 5
GRP 6
GRP 7
GRP 8
L MIX
R MIX
R62
10K
R63
10K
SW12
R51
4K7
R53
100K
C26
33P
C27
100/16
5
6
7
IC6B
TL072
R40
10K
R46
22K
R47
27R
4
5
6
VR8B
10K
R43
10K
V-
1
2
3
POT610KALPS
R39
4K7
C22
33P
R38
560K
TO SOLO SW
ON
D5
LED
LK5
SW7
LK4
TIP
RING
INSERT
RING NORMAL
2
1
3
4
5
JS2
1/4JACK
CHASSIS EARTH
PRE FADER
3
2
4
1
-17V
+17V
5
6
7
8 LK7
LK6 PRE FDR
PRE EQ
PRE
VR9
20K
SW13
SW SPDT
R64
100K
R65
10K
R66
10K
C28
100/16
3
2
1
8
4
IC5A
NE5532
C29
33P
SW14
DIRECT
TIP
RING
R67
75
R68
10K
C31
100/16
C30
33P
R69
10K
R71
75R
DIRECT
R70
10K
2
1
3
4
5
JS3
1/4JACK
AUX 1
AUX 2
AUX 1
AUX 2
R72
10K
R73
10K
R74
10K
R75
10K
3-4
5-6
SW15
VR10
20K
VR11
20K
VR12
20K
-POST FDR
PRE FDR
LK4
LK3
LK2 PRE EQ
EARTH TERMINAL
V+
MIC AMP V+
R83
10
C34
22/25
C35
22/25
9
10
+18V
+48V
0V
+48V
+18V
0V
0V
+18V
R81
10
C32
220/25
C33
220/25
AUX EARTH REF
MIX EARTH REF
AUX POT EARTH
PAN BUFFER EARTH
-18V
-18V
-18V
R82
10
R85
10K
R86
10K
V-
MIC AMP V-
R84
10
LAST R
LAST C
R99
C43
NOTES
LED METERING NOT SHOWN
FROM CUT LED
LK1
LK5
PFL
AFL
SOLO
V-
R78
47K
R79
10K
D6
LED R
SW16
SOLO ENABLE
SOLO AUDIO
AUX 1
AUX 2
R76
10K
R77
10K
Date: February 2, 1995 Sheet 1 of 1
Size Document Number REV
D CD1217-3 A
Title
FORUM MUTE INPUT (PC1340-3)
TEL:(0)81-570-7161 FAX:(0)81-577-3677
DDA, HOUNSLOW, MIDDX, TW3 2EB, ENGLAND.
INSERT
SEND
C32
100U
16V
2
1
3
4
5
CON2
1/4JACK
R80
75R
R79
10K
1 2
LK16
1 2
LK17
1 2
LK18
1 2
LK19
LINK-OPT
1 2
LK20
LINK-OPT
LINKS 16, 17, 18, 21
FOR SINGLE JACK INSERT
EQ
LED2
RED
C30
33P
C31
33P
C29
100U
16V
SW6
2PSUJ
5
6
7
IC7B
NE5532
R74
10K
R73
10K
R75
10K
R76
75R
R77
10K
R78
10K
LED2 LED3
METERINPUT
HIGH PASS
C14
100N
SW5
2PSUJ
5
6
7
IC3B
TL072
C15
220N
R48
15K
R49
30K
R50
10K
0 REV
HIGH PASS FILTER
18dB/OCTAVE, 80Hz
C11
33P
C12
100U
16V
C13
100N
SW4
2PSUJ
3
2
1
8
4
IC3A
TL072
R40
10K
R41
10K
R47
10K
V-
V+
PHASEMIC/LINE GAIN
5
6
7
IC2B
TL072
C9
33P
C10
100U 16V
4
5
6
VR1B
5KRD
R33
3K3
R34
1K5
R36
62R
R35
220K
R37
3K9
R38
1K5
R39
10K
LED2
REVERSE
MIC/LINE
LED1
GRN
C7
1000U
6.3V
C8
100U
16V
1 2
3
VR1A
5KRD
SW3
4PSUJ
R11
10R
R12
100K
R14
7K5
LED1
MIC INPUT
3
2
6
5
1
8
7
4
IC1
SSM2017
C4
220P
8 2
6 4
1
T1 ( OPT)
NTM1
R8
12K
R10
24K
v1+
D1
12V
D2
12V
R7
(OPT)
2K2
-20dB
+48V
MIC
C2
33U
63V
C1
2U2
63V
R1
470R
R3
6K8
R2
6K8
R4
1K8
SW1
2PSUJ
SW2
2PSUJ
R6
360R
+48V
1
2
3
CON5
3WAY
WIR
R203
10R
SPLIT
C3
33U
63V
R5
1K8
C5
10N
R15
100R
1
2
3
CON6
3WAY
MH
R204
10R
v1-
D3
12V
D4
12V
R9
12K
GAIN = 10 TO 60dB
C58
22U
25V
C59
22U
25V
R13
10K
R173
10R
R174
10R
V+ V1+
GAIN = 0 TO 10dB
GAIN = -10 TO +20dB
MIC
LINE
3
2
1
8
4
IC4A
TL072
C17
33P
C16
3N3
1 2
3
VR2
10KB
5
6
7
IC4B
TL072
R51
1K5
R52
1K5
R53
47K
R54
47K
R55
10K
R56
10K
V-
V+
1 2
3
VR3
10KB
3
2
1
8
4
IC5A
TL072
R59
10K
R60
10K
R63
1K2
V-
V+
C21
33P
C19
470N
C18
470N
R64
1K2
R66
47K
V+
V-
C41
33P
C42
100U
16V
3
2
1
8
4
IC6A
NE5532
3
2
1
8
4
IC7A
NE5532
C62
22U
25V
C63
22U
25V
R84
12K
R90
10K
R175
10R
R176
10R
V2+
V3+
V2+ V2-
V2-
R201
10K
INSERT
RETURN
DIRECT
OUT
C40
33P
R81
12K
R82
12K
R83
12K
2
1
3
4
5
CON3
1/4JACK
1
2
LK21
LINK
LINKS 19 AND 20
FOR DOUBLE JACK INSERT
MIX
C36
100U
16V
R95
10K
R96
75R
2
1
3
4
5
CON1
1/4JACK
SW9
4PSUJ
LED10
GRN
R119
10K
LED10
C34
33P
C35
33P
C64
22U
25V
C65
22U
25V
R91
10K
R92
75R
R93
10K
R94
10K
V3+
V3-
V3-
C46
33P
C22
100U
16V
5
6
7
IC5B
TL072
R67
10K
R107
22K
R113
4K7
R114
3K3
R177
10R
R178
10R
V+
V-
R108
22R
C24
2N2
C25
33N
C26
15N
1
2
3
VR6A
100KC
4
5
6
VR6B
100KC
1
2
3
VR5
10KB
1
2
3
VR7
10KB
R61
3K3
R62
3K3
R65
47K
FADER
STANDARD AUTOMATED
1
2
3
VR4A
100KC
4
5
6
VR4B
100KC
C23
4N7
R57
3K3
R58
3K3
123
CON10
3WAY
MH
123
CON11
3WAY
MH
FADER
123
WIR1
3WAY
WIR
123
WIR2
3WAY
WIR
FADER LINK WIRE
V1-V-
LINK FOR -10dBV
LINE INPUT
3
2
1
8
4
IC2A
TL072
C37
33P
C38
33P
C39
100U
16V
1 2
LK3
LINK-OPT
R20
12K
R21
12K
R22
3K
R23
3K
R24
3K
R25
3K
R26
1K
R27
10K
V1+
V1-
LINE
2
1
3
4
5
CON4
1/4JACK
TAPE
1
2
3
CON7
3WAY
MH
D8
1N4148
LED16
RED
LED17
RED
SW16
2PSUJ
SW17
2PSUJ
MUTE1
LED16
C69
47N
VDD
R190
1K
FADER BUFFER
MUTE RET
R101
220K
1
2
3
4
5
6
7
8
9
10
CON9
10WAY
MHL
VSS
C43
220N
R102
680K
C44
33P
C45
220U
25V
5
6
7
IC6B
NE5532
R103
4K7
R104
75R
R105
10K
1 2
LK22
LINK-OPT
AFL
R202
10K
SERIES
SHUNT
V+
V-
V+
14
AI
4
AO
6
AC
2
BI
11
BO
9
BC
13
V-
7
0V
1
0V
3
0V
5
0V
12
0V
10
0V
8
IC13
SSM2402
PAN BUFFER
3
2
1
8
4
IC8A
TL072
5
6
7
IC8B
TL072
C48
33P
1
2
3
VR20A
10KB
4
5
6
VR20B
10KB
R111
10K
R117
3K3
V-
V+
PAN IN
C47
100U
16V
C49
100U
16V
R115
100K
LEDS1
GRN
SW1S
4PSUJ
LEDS1SLEDS1
PANLIN PANLINS
R120
10K
MIXR
MIXL
PANRS PANR
2
4
R125
10K
R126
10K
LED11
GRN
LED12
GRN
SW24
2PSUJ
BUS2
BUS1
GRP1S GRP1
1
3
R118
100K
LEDS2
GRN
LEDS3
GRN
SW2S
2PSUJ
PANRIN PANRINS
MONOIN MONOINS
R109
22K
R110
33R
R112
10K
R116
4K7
V+
14
AI
4
AO
6
AC
2
BI
11
BO
9
BC
13
V-
7
0V
1
0V
3
0V
5
0V
12
0V
10
0V
8
IC15
SSM2402
R137
47K
R138
10K
CUEDC
CUEAUDIO
V-LED
1 2
LK23
LINK
PFL
SERIES
SHUNT
V+
V-
IC15 FITTED ONLY WHEN
PRE FADE AUX MUTING
NOTE
IS REQUIRED.
OTHERWISE LINK
SOLO
MIDI MUTE
MUTE OUT
SW11
2PSUJ
LED24
YEL
123
CON12
3WAY
MH
1 2
LK13
LINK
1 2
LK14
LINK-OPT
1 2
LK15
LINK-OPT
LED24
VDDVDD
MOMENTARY
LOW TO CUT
HIGH TO CUT
R189
100K
TR8
BC182
VDD 5
6
4
IC12B
CD4011 8
9
10
IC12C
CD4011
CUT
RESET
R184
100K
R185
100K
R186
2K2
R187
4K7
R188
150K
C68
22U
25V
TR7
BC182
SW14
2PSUJ MOM
D
5
Q
1
CLK
3
Q
2
R
4
S
6
IC11A
4013
VDD
VDD
VDD
VSS
VSS
VSS
CUT SWITCH
LED18
RED
LED19
RED
D9
1N4148
D10
1N4148
SW18
2PSUJ
MUTE2
MUTE3
1
2
3
CON16
3WAY
MH
LED20
RED
D11
1N4148
D12
1N4148
SW19
2PSUJ
SW20
2PSUJ
MUTE4
MUTE5
SAFE
R196
220K
LED15 LED16
VSS
VSS
R199
220K
1
2
3
IC12A
CD4011
R200
10R
VIN
1
0
V
2
VOUT
3
IC14
78L05
SW28
2PSUJ
LED15
YEL
D5
D6
TR6
BC212
R157
75R
D16
D17
SHUNT
V+LED V+LED V+LED
VSS
ON LAMPR191
100K
R192
100K
R193
100K
R194
100K
TR9
BC212
TR10
BC182
LED4
GRN
R197
75R
TR11
BC212
LED4
LED5
SERIES
LED4
PANRIN
PANLIN
GRP7
GRP5
GRP3
GRP1
PANR
MONOIN
LEDS1
V+LED
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
CON14
16WAY
IDCBX
V-LED
1 2
LK4
LINK-OPT
1 2
LK6
LINK
PINS 4 AND 11
PRE
DIRECT
POST ON
PRE EQ
SW7
2PSUJ
1
2
3
VR16
20KA
LED3
GRN
SW15
4PSUJ
LED3
5
R133
10K
LEDS4
GRN
SW3S
2PSUJ
SW4S
2PSUJ
AUX1
LEDS1
6
R130
10K
R127
10K
R128
10K
LED13
GRN
SW25
2PSUJ
SW26
2PSUJ
BUS3
BUS4
BUS6GRP5S GRP5
GRP3S GRP3
8
R129
10K
R131
10K
R132
10K
LED14
GRN
SW27
2PSUJ
BUS5
BUS7
BUS8
LED4S LED15
GRP7S GRP7
SUBGND
SUB BOARD
7
R134
10K
R135
10K
R136
10K
LEDS5
GRN
SW5S
2PSUJ
AUX4
AUX3
AUX2
PRE
POST ON
PRE EQ
SW8
2PSUJ
1
2
3
VR17
20KA
1
2
3
VR18
20KA
1
2
3
VR19
20KA
1 2
LK7
LINK-OPT
1 2
LK9
LINK
TR1
BC182
R144
100K
R156
100K
LED5
GRN
LED5
LED10
SUBGND
LED4S
PANRINS
PANLINS
GRP7S
GRP5S
GRP3S
GRP1S
PANRS
MONOINS
LEDS1S
SUBGND
V+LED
D7
18V
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
CON15
16WAY
IDCVF
R152
100K
R153
100K
R154
100K
R155
100K
R158
33K
1
2 PL1
1/4"RPB
R198
33KLED1
METERINPUT
V-LED V-LED
C56
220U
25V
C60
22U
25V
R169
10R
R171
10R
+48V
V+
V+LED
VSS
VDD
C70
2U2
63V
C71
2U2
63V
LED21
RED
LED22
RED
D13
1N4148
SW21
2PSUJ
SW22
2PSUJ
+18V
0V
+48V
MUTE6
LED23
RED
D14
1N4148
D15
1N4148
SW23
2PSUJ
-18V
MIXREF
AUXREF
MWKGROUND
MUTE7
MUTE8
LED24
PAN BUFFER EARTH
C57
220U
25V
C61
22U
25V
R161
0R
R162
0R
R170
10R
R172
10R
R195
0R
VSS
V-
V-LED
AUX POT EARTH
R159
10K
R160
10K
C53
2U2
63V
C54
2U2
63V
1 2 3 4 6 9
57
8
IC9
BA6144
R149
15K
R150
910R
R151
47K
V-LED V-LEDV-LED
V+
V-
1 2 3
CON17
3WAY
MH
VCA POWER
C55
22U
25V
TR2
BC182
TR3
BC182
TR4
BC182
TR5
BC182
R145
100K
R146
100K
R147
100K
R148
100K
LED6
GRN
LED7
GRN
LED8
GRN
LED9
RED
V-LED
V-LED
V-LED
+17
+10
0
-7
-13
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
CON8
34WAY
IDCMH
1 2
LK10
LINK-OPT
0V
0V
0V
0V
0V
0V
-18V
-18V
-18V
+18V
+18V
+18V
MIXR
MIXL
CUEAUDIO
BUS1
BUS2
BUS3
BUS4
BUS5
BUS6
BUS7
BUS8
AUX3
+48V
AUXREF
MIXREF
MWKGROUND
AUX6
AUX5
AUX4
AUX2
AUX1
CUEDC
MUTE1
MUTE3
MUTE5
MUTE7
1 2
LK12
LINK
PRE
POST ON
PRE EQ
1
2
3
VR21
20KA
1
2
3
VR22
20KA
SW12
2PSUJ
1 2
3 4
5 6
7 8
9 10
CON13
10WAY
IDCMH
MUTE2
MUTE4
MUTE6
MUTE8
LAST R
LAST C
LAST CON
LAST D
LAST LED
LAST IC
LAST TR
LAST SW
R204
C71
LED24
SW28
LAST VR VR22
LAST LK
IC15
LK23
TR11
D17
CON17
R179
10K
R180
10K
AUX6
AUX5
D
9
Q
13
CLK
11
Q
12
R
1
0
S
8
IC11B
4013
VSS
VSS
12
13
11
IC12D
CD4011
Date: June 30, 1993 Sheet 1 of 1
Size Document Number REV
D CD1191-A A
Title
FORUM STEREO INPUT
Tel: (0)81-570-7161 Fax: (0)81-577-3677
DDA, HOUNSLOW, MIDDX, TW3 2EB, ENGLAND.
R39
1K2
C22
33P
R41
47K
R32
10K
R33
10K
12
13
14
IC4D
TL074
C18
47N
R37
470
C20
470N
1 2
3
VR7A
10KB
R38
1K2
C21
470N
R40
47K
90Hz to 1.3kHz
C16
6N8
R26
10K
R27
10K
12
13
14
IC13D
TL074
R31
470
600Hz TO 8.8kHz
R22
1K5
1 2
3
VR2A
10KB
R23
1K5
C15
33P
C14
3N3
L CUT
L CUT AND R CUT = MONO
R13
75
C9
100U
16V
SW3
2PSUJ
1000U
4
5
6
VR1B
5KRD
R100
75RR975R
R10
100R
H1B
4K7
H1A
4K7
C8
33P
5
6
7
IC2B
TL072
+48V
+48V
INPUT B
SW1
SW DPDT
R11
470
SW2
SW 6PDT
R5
10k
C1
47/63
D1
12V
D2
12V
+IN
-IN
INPUT B
RIAA
LEFT
JR1
JR2
C7
2.2/63
R101
6K8
R102
6K8
R2
6K8
R1
6K8
R4
16K2R316K2
XL2
XL3
-IN
+IN
RIAA
INPUT B
RIGHT
R103
16K2
R104
16K2
JR3
JR4
R12
10
XL2
XL3
D3
12V
D4
12V
R7
2K2
R6
10K
C2
47/63
R8
24K
C3
220P
L+R-3dB
3
2
6
5
1
8
7
4
IC1
SSM2017
R118
10R
C6
100U
16V
H1C
4K7
R15
3K3
C10
33P
3
2
1
8
4
IC12A
TL072
H1D
4K7
H101A
4K7
R115
3K3
R CUT
R14
10K
C11
75
C11
100U
16V
R17
10K
SW5
2PSUJ
+
-
R24
47K
R25
47K
5
6
7
IC3B
TL074
4
5
6
VR4B
10KB
R28
220K
3
2
1
4
11IC3A
TL074
R29
10K
+
-
C17
10N
4
5
6
VR3B
100KC
10
9
8
IC3C
TL074
R30
6K8
3
2
1
4
1
1
IC4A
TL074
4
5
6
VR6B
10KB
R34
220K
R35
10K
C19
68N
4
5
6
VR5B
100KC
R36
6K8
10
9
8
IC4C
TL074
5
6
7
IC4B
TL074
EQ
R4275C24
100u
R43
10K
SW6
SW DPDT
C23
33P
R143
10K
C124
100u
R142
75
R141
47K
C122
33P
R139
1K2
C123
33P
10
9
8
IC15C
TL074
R140
47K
C121
470N
4 5
6
VR7B
10KB
C120
470N
R138
1K2
R132
10K
R133
10K
12
13
14
IC15D
TL074
C119
68N
10
9
8
IC15C
TL074
1
2
3
VR5A 100KC
R137
470
C118
47N
-
90Hz to 1.3kHz
R135
10K
3
2
1
4
1
1
IC15A
TL074
1
2
3
VR6A
10KB
R127
10K
R126
10K
12
13
14
IC14D
TL074
C117
10N
10
9
8
IC14C
TL074
R131
470
1
2
3
VR3A 100KC
C116
6N8
600Hz TO 8.8kHz
-
R129
10K
3
2
1
4
1
1
IC14A
TL074
1
2
3
VR4A
10KB
R123
1K5
4 5
6
VR2B
10KB
R122
1K5
C115
33P
C114
3N3R124
47K
R125
47K
5
6
7
IC14B
TL074
R116
75
C111
100U
16V
R117
10K
H101D
4K7
C108
33P
3
2
1
8
4
IC12A
TL072
H101C
4K7
SW4
SW DPDT
C110
33P
5
6
7
IC12B
TL072
H101B
4K7
3
2
1
8
4
IC13A
TL072
C12
33P
R19
4K7
R18
4K7
C106
100U
16V
C105
1000U
1
2
3
VR1A
5KRD
R110
100R
3
2
6
5
1
8
7
4
IC11
SSM2017
R109
7R5
D102
12V
D101
12V
R105
10K
R107
2K2
C101
47/63
R111
18
XLR1
C51
10N
C103
220P
R108
24K
D104
12V
D103
12V
R106
10K
C102
47/63
R20
75
1
2
3
A
R49
220K
R50
680K
C29
220N
5
6
7
IC6B
NE5532
0 REV
R113
75R
R21
10K
C13
100U
16V
R53
75
C31
220U
16V
LM
+
BALANCE
+3dB,-6dB
R114
10K
C109
100U
16V
R128
220K
1
2
3
VR12A
10KB
R60
5
6
7
IC8B
NE5532
+
R134
220K
R130
6K8
1% RESISTOR
R136
6K8
SW11
SW DPDT
R
METER_R_INPUT
METER_L_INPUT
CN6-15
CN6-13
CN6-11
CN6-9
CN6-7
CN6-5
1-2
3-4
5-6
R165
10K
R65
10K
R66
10K
R166
10K
R67
10K
R167
10K
SW12
SW DPDT
SW13
SW DPDT
R63
75
C36
220U
16V
R64
10K
R163
75
C136
220U
16V
R164
10K
R58
10K
R59
3K3
R158
10K
4
5
6
VR12B
10KB
R159
3K3
R160
C35
33P
R62
3K3
R61
8K2
3
2
1
8
4
IC8A
NE5532
C135
33P
R52
10K
H3A
4K7
H3B
4K7
R54
3K3
C32
33P
3
2
1
8
4
IC7A
TL072
H3C
4K7
JR12
JR11
R51
4K7
C30
33P
ON
SW15
SW 4PDT
JR9
JR10
PRE FADE MONO
L+R-3dB
H2A
4K7
H2A
4K7
R46
3K3
C25
33P
3
2
1
8
4
IC5A
TL072
CN4-1
CN4-2
CN4-3
CN4-8
CN4-9
CN4-10
CN5-1
CN5-2
CN5-3
CN5-4
JR13
D5
GREEN
1
2
3
A
R149
220K
R150
680K
C129
220N
3
2
1
8
4
IC6A
NE5532
C130
33P
R151
4K7
L+R-3dB
POST FADE MONO
R152
10K
R153
75
C131
220U
16V
RM
LL1LL2
R162
3K3
R161
8K2
H3D
4K7
C33
33P
5
6
7
IC7B
TL072
R55
75
C34
100U
16V
D8
RED
SW16
SW DPDT
J2
R56
10K
PFL
PFL
CN6-3
CN6-1
7-8
CN6-19
CN6-17
MIX
R68
10K
R168
10K
R69
10K
R169
10K
SW14
SW DPDT
SW10
SW DPDT
LL2
R85
100K
R84
100K
R83
100K
Q2
BC550
D12
GREEN
D13
GREENQ3
BC550
Q4
BC550
D14
GREEN
+17V
D11
18U
D10
1N4148
R79
10K
D9
1N4148
6x100K H4
CN6-2
CN6-4
SOLO ENABLE
SOLO AUDIO
METER_R_INPUT
METER_L_INPUT
C37
100u
R78
10K
5
6
7
IC9B
TL072
R70
10K
R71
47K
SW7
SW DPDT
SW8
SW DPDT
J3
J4
VR9
20A
VR8
20KA
PRE
LM
RM
H2D
4K7
C26
33PH2C
4K7
5
6
7
IC5B
TL072
R47
75
C27
100U
16V
R48
10K
LL1
CN6-26
EARTH SENSING RESISTOR
AUX EARTH
R88
10K
-17V
+17V
+17V
R44
62
Q1
BC560
R94
10R
R96
10R
R98
10R
1N4148
1N4148
CN4-4
+17V
-17V
CN4-6
CN4-7
CN4-5
CN6-32
CN6-30
CN6-28
R45
30K
R90
10R
R92
10R
CN6-16
CN6-14
CN6-12
CN6-10
CN6-8
CN6-6
CN6-24
CN6-22
CN6-20
C41
220U
25V
C42
220U
25V
R91
10R
R93
10R
C43
22U
25V
C44
22U
25V
+V1 +V2 +V3 +V4
-V1 -V2 -V3 -V 4
-17V
R95
10R
R97
10R
R99
10R
C45
22U
25V
C47
22U
25V
C49
22U
25V
C46
22U
25V
C48
22U
25V
C50
22U
25V
C4
22U
25V
C104
22U
25V
CN6-18
BALANCE POT
EARTH SENSING RESISTOR
MAIN GROUND SPADE
CN7
CN2-34
CN2-33
+48V
R89
10K
NOTE METER NOT SHOWN
SEE PRO INPUT SCHEMATIC
J1
VR10
20KA
VR11
20KA
SW9
SW 4PDT
PRE
5-6
CN6-27
CN6-25
CN6-23
CN6-21
CN6-29
CN6-31
AUX1
AUX2
AUX3
AUX4
AUX5
AUX6
R178
10K
C137
100u
3
2
1
8
4
IC9A
TL072
R72
10K
R73
10K
R77 10K
R76 10K
R75 10K
R74 10K
D109
1N4148
R179
10K
D110
1N4148
R80
91K
C40
1U0
R81
18K
R57
18K
R82
47K C38
2U2
1 2 3 4 6 9
57
8
IC10
BA6144
-17V -1 7V
-17V -17V
C39
C22U
R87
100K
R86
100K
Q5
BC550
Q6
BC550
D16
RED
D15
GREEN
-17V -17V
-17V
Date: January 16, 1995 Sheet 1 of 1
Size Document Number REV
B CD1260-1 A
Title
FORUM STEREO MUTE SUB (PC1377-B)
TEL: (0)81-570-7161 FAX: (0)81-577-3677
DDA, HOUNSLOW, MIDDX, TW3 2EB, ENGLAND.
SW9
2PSUJ
LED9
RED
LED9
LED1
RED
SW1
2PSUJ
MUTE1
D1
D2
LED2
RED
SW2
2PSUJ
MIDI MUTE
VSS
R5
100K
LEDIN
VDDVDD
R7
100K
TR1
BC212
TR2
BC182
R9
100K
CUT
R6
47K
8
9
10
IC3C
CD4001
5
6
4
IC3B
CD4001
VSS 1
2
3
IC3A
CD4001
R3
22K
1
2
3
CON8
3WAYMH
VSS
VDD
R2
1K
C1
47N
C6
100P
D3
LED3
RED
SW3
2PSUJ
MUTE2
MUTE3
MUTE4
D4
LED4
RED
SW4
2PSUJ
VDD
VSS
R1
100K
C3
22U
25V
CN4/2
R10
100K
R4
47K
D9 TR5
J111
D12
C2
470N
V-
R8
100K
LEDOUT
V+
SERIES
V+
14
AI
4
AO
6
AC
2
BI
11
BO
9
BC
13
V-
7
0V
1
0V
3
0V
5
0V
12
0V
10
0V
8
IC1
SSM2402
V+
12
13
11
IC3D
CD4001
CN4/3
CN4/2
1
2
3
4
5
6
7
8
9
10
CON1
10WAY
MHL
CN4/3
CN4/7
CN4/6
CN4/5
CN4/8
CN4/9
LEDIN
LEDOUT
CN4/2
VSS
R16
100K
VSS
VDD
CN4/3
TR4
BC212
R14
1K
R15
10K
D5
LED5
RED
SW5
2PSUJ
MUTE5
MUTE6
D6
LED6
RED
SW6
2PSUJ
MUTE1
MUTE3
MUTE5
VSS
1 2
3 4
5 6
7 8
9 10
CON3
10WAY
IDCMH
MUTE2
MUTE4
MUTE6 RIGHT
LEFT
V-V-
C7
220P
V-
CN4/4
CN4/1
1
2
3
CON2
3WAY
MH
SCREEN
SCREEN
CN5/4
CN5/1
AUDIO IN
AUDIO OUT
AUDIO IN
AUDIO OUT
V-
V+
SHUNT
V+
14
AI
4
AO
6
AC
2
BI
11
BO
9
BC
13
V-
7
0V
1
0V
3
0V
5
0V
12
0V
10
0V
8
IC2
SSM2402
V-
V+
R11
75R
V+
D10
D11
MUTE8MUTE7
D7
LED7
RED
LED8
RED
SW7
2PSUJ
MUTE7
MUTE8
D8
SW8
2PSUJ
V-
V+
R13
180R
C4
2U2
63V
C5
2U2
63V
VIN
1
0
V
2
VOUT
3
IC4
78L05
VSS
VDD
V-
R12
33K
LED9
TR3
BC212
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