DDA forum-monitor Schematic
Forum Monitor
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 Monitor 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: February 2, 1995 Sheet 1 of 1
Size Document Number REV
D CD1204-2 B
Title
FORUM MONITOR INPUT
DDA, HOUNSLOW, MIDDX, TW3 2EB, ENGLAND.
C32
100U
16V
INSERT
SEND
R76
75R
R79
10K
2
1
3
4
5
CON2
1/4JACK
EQ
LED2
RED
C31
33P
C29
100U
16V
LED2 LED3
SW6
2PSUJ
5
6
7
IC7B
NE5532
R74
10K
R73
10K
HIGH PASS
C14
100N
SW5
2PSUJ
5
6
7
IC3B
TL072
C15
220N
R48
15K
R49
30K
R50
10K
0 REV
HIGH PASS FILTER
C11
33P
C12
100U
16V
C13
100N
V-
V+
18dB/OCTAVE, 80Hz
SW4
2PSUJ
3
2
1
8
4
IC3A
TL072
R40
10K
R41
10K
R47
10K
0 REVERSEMIC/LINE GAIN
5
6
7
IC2B
TL072
C9
33P
C10
100U 16V
LED2
4
5
6
VR1B
5KRD
R33
3K3
R34
1K5
R36
62R
R35
220K
R37
3K9
R38
1K5
R39
10K
MIC/LINE
LED1
GRN
C7
1000U
6.3V
C8
100U
16V
LED1
1 2
3
VR1A
5KRD
SW3
4PSUJ
R11
10R
R12
100K
R14
7K5
MIC INPUT
3
2
6
5
1
8
7
4
IC1
SSM2017
C4
220P
C2
33U
63V
v1+
R7(OPT)
2K2
R8
12K
R10
24K
D1
12V
D2
12V
-20dB
+48V
MIC
C1
2U2
63V
+48V
8 2
6 4
1
T1 (OPT)
NTM1
R1
470R
R3
6K8
R2
6K8
R4
1K8
SW1
2PSUJ
SW2
2PSUJ
R6
360R
1
2
3
CON5
3WAY
WIR
LK1
10R
R5
1K8
C5
10N
SPLIT
R15
100R
1
2
3
CON6
3WAY
MH
LK2
10R
LK2
10R
C3
33U
63V
C58
22U
25V
C59
22U
25V
V+ V1+
v1-
R9
12K
R173
10R
R174
10R
D3
12V
D4
12V GAIN = 10 TO 60dB
R13
10K
3
2
1
8
4
IC4A
TL072
C17
33P
C16
3N3
V-
V+
1 2
3
VR2
10KB
5
6
7
IC4B
TL072
GAIN = 0 TO 10dB
GAIN = -10 TO +20dB
MIC
LINE
R51
1K5
R52
1K5
R53
47K
R54
47K
R55
10K
R56
10K
1 2
3
VR3
10KB
3
2
1
8
4
IC5A
TL072
V-
V+
R59
10K
R60
10K
R63
1K2
C21
33P
C19
470N
C18
470N
V+
R64
1K2
R66
47K
C30
33P
C41
33P
METERINPUT
C42
100U
16V
3
2
1
8
4
IC7A
NE5532
V2+
V2-
V2+
C62
22U
25V
R75
10K
R175
10R
INSERT
RETURN
R77
10K
R78
10K
R80
75R
R81
12K
R82
12K
2
1
3
4
5
CON3
1/4JACK
C40
33P
C36
100U
16V
DIRECT
OUT
R83
12K
R92
75R
R95
10K
2
1
3
4
5
CON1
1/4JACK
3
2
1
8
4
IC6A
NE5532
V3+
V3-
V+ V3+
V2-
C63
22U
25V
R84
12K
R90
10K
R176
10R
R177
10R
C22
100U
16V
5
6
7
IC5B
TL072
V-
R67
10K
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
1
2
3
VR4A
100KC
4
5
6
VR4B
100KC
C23
4N7
R57
3K3
R58
3K3
C38
33P
C39
100U
16V
1 2
LK3
LINK-OPT
V1-V-
R25
3K
R26
1K
R27
10K
LINE
LINK FOR -10dBV
LINE INPUT
3
2
1
8
4
IC2A
TL072
C37
33P
V1+
V1-
R20
12K
R21
12K
R22
3K
R23
3K
R24
3K
2
1
3
4
5
CON4
1/4JACK
METERINPUT
R152
100K
R153
100K
R154
100K
R155
100K
R156
100K
LED6
V+LED
LED6
GRN
D7
18V
R179
100K
123
CON7
3WAY
PIN
FADER BUFFER
C45
220U
25V
C43
220N
5
6
7
IC6B
NE5532
R104
75RR101
220K
R102
680K
ON
LED4 LED5
SW10
4PSUJ
LED4
GRN
R107
22K
C34
33P
C35
33P
C46
33P
V3-
C64
22U
25V
C65
22U
25V
V-
R91
10K
R108
22R
R113
4K7
R114
3K3
R178
10R
LED3 LED4
MIX
LED3
GRN
SW9
4PSUJ
R93
10K
R94
10K
R96
75R
MIXR
MIXL
MIXREFSW
R115
100K
R119
4K7
R120
4K7
PAN BUFFER
3
2
1
8
4
IC8A
TL072
5
6
7
IC8B
TL072
C48
33P
C47
100U
16V
C49
100U
16V
V-
V+1
2
3
VR20A
10KB
4
5
6
VR20B
10KB
R111
10K
R112
10K
R117
3K3
POST ON
PRE ON
1 2
LK4
LINK
1 2
LK5
LINK-OPT
1 2
LK6
LINK-OPT
PRE EQ
SOLO
LED5 LED6
R105
3K6
R106
10K
R103
4K7
C44
33P
R180
240R
PR1
500R
1/4H
+17
+10
0
-7
-13
C55
22U
25V
V-LED
V-LED
LED7
GRN
LED8
GRN
LED9
GRN
LED10
RED
TR1
BC182
TR2
BC182
TR3
BC182
TR4
BC182
TR5
BC182
R144
100K
R145
100K
R146
100K
R147
100K
R148
100K
C53
2U2
63V
C54
2U2
63V
V-LED V-LED
V-LED
V-LED
1 2 3 4 6 9
57
8
IC9
BA6144
R149
15K
R150
910R
R151
47K
CUE
IPCUE
IPCUEAUD
SW11
2PSUJ
LED5
YEL
R137
47K
R138
10K
R109
22K
R110
33R
PRE
SW7
2PSUJ
1 2
LK8
LINK-OPT
1
2
3
VR16
20KA
R116
4K7
1
2
3
VR12
20KA
R133
12K
1 2
LK9
LINK
1 2
LK7
LINK-OPT
PRE FADER
POST FADER
PRE/POST
1
2
3
VR8
20KA
R118
100K
R125
12K
R129
12K
BUS2
BUS3
BUS5
BUS6
BUS7
BUS1
1
2
3
VR9
20KA
1
2
3
VR10
20KA
R126
12K
R127
12K
R130
12K
R131
12K
MTX9
MTX10
MTX11
PRE
SW8
2PSUJ
1
2
3
VR13
20KA
1
2
3
VR14
20KA
1
2
3
VR17
20KA
1
2
3
VR18
20KA
R134
12K
R135
12K
+48V
V+
V+LED
1
2 PL1
1/4"RPB
+18V
0V
+48V
C56
220U
25V
C57
220U
25V
C60
22U
25V
C61
22U
25V
R169
10R
R171
10R
PAN BUFFER EARTH
-18V
MIXREF
BUSREF
MWKGROUND
MIXREFSW
R159
1K
R160
1K
R161
0R
R162
0R
R170
10R
R172
10R
V-
V-LED
LED1
V+LED V+LED
V-LED
MIXR
MIXL
BUS1
BUS2
BUS3
BUS4
BUS5
BUS6
BUS7
BUS8
MTX9
MTX10
MTX11
MTX12
+48V
TR6
BC212
R157
75R
R158
33K
tback
opcue
D5
D6
0V
0V
0V
0V
0V
-18V
-18V
-18V
+18V
+18V
+18V
IPCUE
IPCUEAUD
BUSREF
MIXREF
MWKGROUND
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
opcueaud
LAST R
LAST C
LAST CON
LAST D
LAST LED
LAST IC
LAST TR
LAST SW
R180
C65
CON8
D7
TR6
LED10
SW11
IC9
LAST VR VR19
LAST LK LK8
MTX12
1
2
3
VR15
20KA1
2
3
VR19
20KA
R136
12K
BUS4BUS8
1
2
3
VR11
20KA
R128
12K
R132
12K
Date: November 10, 1994 Sheet 1 of 1
Size Document Number REV
D CD1205-2 A
Title
FORUM MONITOR MASTER
DDA, HOUNSLOW, MDDX, TW3 2EB, ENGLAND
1 2
LK5
1 2
LK6
12 34 5 6
CON23
6WAY
FHR
R191
10K
R192
10K
LEFT
12 3
CON9
3WAY
WIR
D38
D40
8
6
4
3
7
215
IC5
SSM2142
C93
100U
16V
C94
100U
16V
C95
100U
16V
C96
22U
25V
C97
22U
25V
V1+
V1-
R199
10K
D37
D39
R193
100R
R194
100R
LEFT FADER
C13
100U
16V
C15
100U
16V
R25
680K
3
2
1
8
4
IC4A
TL072
C14
220N
V1+
V1-
123
CON7
3WAYPIN
R21
10K
R22
10K
R24
10K
C11
33P
C12
33P
3
2
1
8
4
IC3A
NE5532
R23
10K
V1+
V1-
INSERT RETURN
LEFT
RIGHT
2 1345
CON11
1/4JACK
2 1345
CON12
1/4JACK
LEFT
2 1345
CON5
1/4JACK
INSERT
RIGHT
SEND
2 1345
CON6
1/4JACK
R8
10K
R9
10K
R10
75R
R16
10K
C3
33P
C4
33P
C5
100U
16V
5
6
7
IC3B
NE5532
C88
10N
R7
75R
R4
10K
R5
10K
R6
10K
V1+
V1-
MIX
LEFT
R2
100K
C2
33P
C6
22P
3
2
8 567
4
IC1
NE5534
R1
75R
R3
4K7
L1
0H
LMIX
MIXREF
V1+
V1-
C1
22P
MIX
RIGHT
R11
75R
R12
100K
C7
33P
3
2
8 567
4
IC2
NE5534
R13
4K7
L2
0H
MIXREF
RMIX
V1+
V1-
R14
10K
R15
10K
R17
75R
R18
10K
R19
10K
R20
75R
C8
33P
C9
33P
C10
100U
16V
5
67IC6B
NE5532
INSERT
SEND
V+
V-LED V+L ED
1
2
3
4
5
6
CON22
6WAY
WIR
INSERT RETURN
R31
10K
R32
10K
R33
10K
R34
10K
C22
33P
3
2
1
8
4
IC6A
NE5532
V1+
V1-
RIGHT FADER
C23
100U
16V
C25
100U
16V
R35
680K
5
6
7
IC4B
TL072
C24
220N
123
CON8
3WAYPIN
C98
100U
16V
C99
100U
16V
C100
100U
16V
C101
22U
25V
C102
22U
25V
8
6
4
3
7
215
IC7
SSM2142
V1+
V1-
R200
10K
D41
D43
R197
100R
R198
100R
RIGHT
12 34 5 6
CON24
6WAY
FHR
1 2
LK7
1 2
LK8
R195
10K
R196
10K
12 3
CON10
3WAY
WIR
D42
D44
LEFT
MONITOR
LEFT
MONITOR
R89
10K
R91
10K
C53
100U
16V
R88
75R
2 1345
CON3
1/4JACK
R90
10K
3
2
1
8
4
IC12A
NE5532
C52
33P
R82
10K
V1+
V1-
R86
4K7
R87
4K7
R80
33K
C47 33P
C48
100U
16V
3
2
1
8
4
IC11A
TL072
R81
100K
R84
100K
V1-
V1+
MONITOR
MONITOR
RIGHT
LEFT
123
CON19
3WAYPIN
123
CON20
3WAYPIN
C21
33P
1
2
3
VR2A
10KA
D35
SW11
2PSUJ
MONO
D34
RED
R78
2K2
C43
33P
C44
100U
16V
3
2
1
8
4
IC10A
TL072
R76
10K
V1-
V1+
R49
10K
R50
10K
TR1
J111
TR2
J111
V1-
METER
PCB
LEFT
SW10
4PSUJ
LEFT
EXT LEFT
EXT RIGHT
V-
0V
CUE ONLY
D36
GRN
V1-
V1+
D36
R202
22K
R203
3K6
R205
22K
R206
3K6
5
6
7
IC8B
TL072
3
2
1
8
4
IC8A
TL072
R201
10K
PR3
5K 1/4V
PR4
5K 1/4VR204
10K
3
2
1
8
4
IC9A
NE5532
V1+
IPCUEAUD
R64
10K
R67
10K
C38
33P
5
6
7
IC9B
NE5532
C39
100U
16V
R66
4K7
R65
33K
1
2
3
VR5
10KB
R59
10K
R60
10K
TR3
J111
TR4
J111
R184
15K
R77
10K
R79
2K2
C45
33P
C46
100U
16V
5
6
7
IC10B
TL072
V1+
TR14
J111
4
5
6
VR2B
10KA
V+LED
PHONES
R40
3K6
D13
18V
R83
33K
C49 33P
C50
100U
16V
5
6
7
IC11B
TL072
V+LED V+LED
D14
18V
D15
18V
R97
10K
5
6
7
IC12B
NE5532
C55
33P
R85
10K
C51
33P
C54
33P
R93
4K7
R94
4K7
RIGHT
MONITOR
R92
75R
R96
10K
R98
10K
R99
75R
C56
100U 16V
R95
75R
2 1345
CON4
1/4JACK
R119
33R
TR5
BC182
V2+
R117
10K
D36
V-LED
PHONES
ON
SW2
4PSUJ
D35
D23
GRN
D24
GRN
D25
GRN
D26
GRN
D27
GRN
D35
GRN
R172
270K
V+
1
I
2
I
/
P
3
T
/
C
4
D
1
2
5
D
1
1
6
D
1
0
7
D
9
8
D
8
1
0
D
7
1
1
D
6
1
2
D
5
1
3
D
4
1
4
D
3
1
5
D
2
1
6
D
1
1
7
0
V
9
D
O
T
1
8
IC17
BA683A
R175
10K
R173
56K
C77
10U
16V
V+LED
D12
18V
D16
RED
D17
RED
D18
RED
D19
RED
D20
GRN
D21
GRN
D22
GRN
C75
22U
25V
V-LED
R69
100K
TR15
J111
D29
TR10
BC182
R73
47K
C42
10N
V1+
R68
100K
V1+
V1+
TR17
BC212
R185
15K
R208
100K
R72
150K
D28
SOLO
LEVEL
V1+
V1+
TR11
BC212
R189
47K
R188
47K
C92
10N
D32
R63
10K
R62
75R
C37
33P
C41
10N
V1+
V1-
V1-
R71
47K
R74
47K
OPCUEAUD
R186
100K
TR12
J175
TR13
J111
C103
100N
D31
D45
D30
TR9
BC182
C40
2U2
63V
V1-
V1-V1-
INPUT
CUE
IPCUE
INPUT CUE
R70
220K
+48V
R209
6K8
R210
6K8
LINK FOR +48V
PHANTOM POWER
1 2
LK3
LINK-OPT
V1-
V1-V1-
V1-
OUTPUT
CUE
R75
4K7
OPCUE
OUTPUT CUE
C91
2U2
63V
TR16
BC182
R187
220K
R212
10K
C107
33U
63V
D46
12V
D4
YEL
V1-
V1-
R190
4K7
1 2
3
VR3A
5KRD
C67
1000U
6.3V
V1+
R218
10R
D33
YEL
SW4
4PSUJ
R171
2K2
TALKBACK
PR2
5K
1/4V
R174
10K
C76
220N
0.2
V-LED
V-LED
V-LED
RIGHT/CUE METER
PR1
500R
1/4V
R116
10K
R118
10K
C63
33P
R114
680K
3
2
1
8
4
IC14A
TL072
V2+
V2-
R115
1K
C105
220N
R215
220K
D6
1N4148
D5
1N4148
PHONES
R120
33R
R121
10K
R122
75R
2
1
3
4
5
CON15
1/4JACK
C64
220U 25V
TR6
BC212
V2-
C86
1000U
25V
C87
1000U
25V
V+ V2+
R180
47R
1/8W
R128
33R
R129
33R R130
10K
R131
75R
TR7
BC182
TR8
BC212
C66
220U 25V
V2+
V2-
V- V2-
R181
47R
R125
10K
R126
10K
R127
10K
C65
33P
5
6
7
IC14B
TL072
R123
680K
C106
220N
D7
1N4148
D8
1N4148
R216
220K
LMIX
RMIX
MIXREF
TBACK
R146
10R
R165
4K7
R166
4K7
R167
4K7
MIX
SW5
4PSUJ
R135
10K
C70
100U 16V
5
6
7
IC15B
TL072
C89
100U
16V
R183
33R
1
2
3
VR4
10KA
R133
47K
3
2
1
8
4
IC15A
TL072
C73
100U
16V
V1+
V1-
TALKBACK
C68
100U
16V
V1-
R217
47K
3
2
6
5
1
8
7
4
IC18
SSM2017
R211
2K2
R214
24K
R213
10K
C104
220P
C108
33U
63V
D47
12V
D48
12V
D49
12V
TALKBACK
MIC
C74
10N
MWKGROUND
R170
100R
R207
0R
1
2
3
CON16
3WAY
WIR
FRONT
TALKBACK
MIC
REAR
1
2
3
CON25
3WAY
WIR
R176
10R
R177
10R
C80
22U
25V
C81
22U
25V
C78
220U
25V
C79
220U
25V
0V
+48V
1
2
3
4
5
6
7
8
CON21
8WAY
AMPM
POWER
V-
V+
+18V
-18V
R136
150R
R178
10R
R179
10R
C82
22U
25V
C83
22U
25V
1
CON18
1/4RPB
V1+
V+LED
V1-
V-LED
C84
22U
25V
C85
22U
25V
R137
18K
R138
9K1
R139
6K2
3
2
1
8
4
IC16A
TL072
C71
100N
C72
100N
V1+
V1-
OSCILLATOR
OSC ON
R140
8K2
R141
820R
R142
10K
SW6
4PSUJ
5
6
7
IC16B
TL072
R144
3K6
V1+
R143
10K
D9
1N4148
D10
1N4148
D11
RED
V1-
C90
33U
63V
0V
0V
0V
0V
0V
RMIX
LMIX
IPCUE
IPCUEAUD
MIXREF
MWKGROUND
TBACK
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
CON1
34WAY
IDCMH
MTX9
MTX10
MTX11
MTX12
BUS1
BUS2
BUS3
BUS4
BUS5
BUS6
BUS7
BUS8
OPCUEAUD
OPCUE
BUSREF
+48V
V+
V-
LAST R =
LAST C =
LAST D =
LAST IC =
LAST TR =
R218
D49
TR17
IC18
LAST VR =
LAST PR =
LAST SW =
PR4
VR5
CON25LAST CON =
4
5
6
VR3B
5KRD
R124
1K
SW11
C108