Alto ACL2 Service Manual
Service Manual
Model: ACL2
Compressor/Limiter/Gate
www.altoproaudio.com
Version: 1.1
CONTENTS
1. Specification
2. Block Diagram
3. Schematic Diagram
4. Printed Circuit Board
5. Wiring Diagram
6. Test Procedure
7. Electrical Parts List
8. Exploded Views & Mechanical Parts List
9. Troubleshooting
10. Notes
SPECIFICATIONS FOR ACL2
AUDIO INPUT
Connectors XLR and 1/4” TRS (Pin 2 and Tip hot)
Type Electronically balanced/unbalanced
Impedance Balanced >50Kohm, Unbalanced>25Kohm
Max input level >+24dBu balanced and unbalanced
CMRR Typically>50dB at 1KHz
AUDIO OUTPUT
Connectors XLR and 1/4” TRS (Pin 2 and Tip hot)
Type Electronically balanced/unbalanced
Impedance Balanced 120ohm, Unbalanced>60ohm
Max output level >+21dBu,+20dBm balanced and unbalanced
SYSTEM SPECIFICATIONS
Bandwidth 22HZ to 22KHz, +0/-0.5dB
Frequency Response 10Hz to 30kHz,+0/-3dB
Noise >-90dBrA, unweighted, 22Hz to 22kHz
THD
<0.008% Typical at +4dBu, 1kHz, unity gain
<0.04% Typical at +20dBu, 1kHz, unity gain
IMD <0.1% Typical SMPTE
Crosstalk
Stereo Coupling True RMS detection
<-100dB, 22Hz to 22Khz
COMPRESSOR SECTION
Type Interactive Compressor (Interactive Knee Adaptation)
Threshold variable (-40dB to +20dB)
Ratio variable (1 to LIM)
Manual Attack Time variable 0.1ms to 200ms / 20dB
Manual Release Time variable from 50 ms to 4s / 20dB
Auto Attack Time Typical 15ms at 10dB, 5ms at 20dB, 3ms at 30dB
Auto Release Time Program dependent, typical 125dB/s
Output level variable (-20dB to +20dB)
INDICATORS
GAIN REDUCTION
IN/OUT 1 LED for indication of IN/OUT.
AUTO LED indicator for each
12 element LED display:
1/2/4/6/9/12/15/18/21/24/27/30 dB.
POWER SUPPLY
USA/Canada ~120VAC, 60Hz
U.K./Australia ~240VAC, 50Hz
Mains Voltages
Fuse
Power consumption 10Watts
Mains Connection Standard IEC receptacle
Europe ~230VAC, 50Hz
General Export Model
100-120VAC :200mA (SLOW-BLOW)
200-240VAC : 100mA (SLOW-BLOW)
~100-120VAC,
~200-240VAC, 50-60Hz
PHYSICAL
Dimension W(483.0)*D(198.0)*H(44.2) mm
Net Weight 3Kg
D
8
C
B
A
AUDIO OUTPUT2
7654321
IN/OUT
SW1
SW-A 2- 1
A
OUTPUT
AUDIO OUTPUT2
IN/OUT
SW1
SW- A2- 1
A
OUTPUT
DI3 HBJO SFEVDUJPO NFUFS
PVUQVU
ESJWFS
DI2 HBJO SFEVDUJPO NFUFS
PVUQVU
ESJWFS
BDM3 CMPDL EJBHSBN
WDB
UIBU3261B
TFSWP
JOQVU
TUBHF
CBMBODFE
AUDIO INPUT1
SIDE-CHAIN1
A
RELE ASE
AUTO
SW2
A
DJSDVJUSZ
BVUP DPNQSFTTPS
BVUP HBUF DJSDVJUSZ
ATTACK
A
RATI O
BVUP HBUF DJSDVJUSZ
A
RELE ASE
AUTO
SW2
A
DJSDVJUSZ
BVUP DPNQSFTTPS
ATTACK
A
RATI O
WDB
UIBU3261B
CLOSE
BVEJP
EFUFDUPS
A
THRESHOLD
A
BVEJP
THRESHOLD
EFUFDUPS
TFSWP
JOQVU
TUBHF
CBMBODFE
AUDIO INPUT2
CLOSE
BVEJP
A
EFUFDUPS
THRESHOLD
SIDE-CHAIN2
A
BVEJP
THRESHOLD
EFUFDUPS
1 2 3 4 5 6 78
D
C
B
A
D
C
B
A
15V
8
7654321
312
IC3E
LM 339
411
IC1E
TL 064
84
IC2C
4580
312
IC4E
LM 339
CN3
15V -15V
LD12
LD11
LD10
RED
LD9
RED
LD8
RED
LD7
RED
2
13
14
IC9A
LM 339
IC9D
IC9C
LM 339
R2
82K
-15V
LM 339
8
9
10
11
R76
5.1K
R66
10K
1
IC9B
LM 339
5
6
7
4
R93
R77
5.1K
RED
RED
14
IC8C
LM 339
IC8D
LM 339
8
9
11
2K
3.9K
R85
-15V
V
V-
15V
312
IC9E
LM 339
312
IC8E
LM 339
411
IC6E
TL 064
R139
100R
V
V-
411
IC5E
TL 064
C39
100U/25V
123
3P2.5
LD14
RED
LD13
RED
2
13
IC8A
IC8B
LM 339
LM 339
5
7
4
10
2K
R86
R1221KR123
-15V
V
V-
V
V-
Q10
LD16
IC3D
BC 557B
R111
47K
LD18
RED
LD17
RED
RED
2
13
LM 339
IC3A
LM 339
10
11
2K
2K
R88
1
IC3B
LM 339
5
6
7
4
1K
R124
R121
1K
LD19
RED
14
IC19C
LM 339
8
9
R4
82K
-15V
LD21
RED
LD20
RED
2
13
IC19A
LM 339
IC19D
LM 339
5
10
11
R79
5.1K
R70
10K
LD23
LD22
RED
1
IC19B
LM 339
IC18C
6
7
4
R94
3.9K
R80
5.1K
R82
100R 1/4W
15V
Q9
BC 557B
LD15
RED
1
14
IC3C
LM 339
8
9
6
1K
R87
15V
312
IC13E
LM 339
411
IC11E
TL 064
84
IC12C
4580
312
IC14E
LM339
LD24
RED
RED
13
14
LM 339
IC18D
LM 339
8
9
11
2K
R89
-15V
V
V-
15V
312
IC19E
LM 339
312
IC18E
LM 339
411
IC16E
TL 064
R140
100R
V
V-
411
IC15E
TL 064
C40
100U/25V
LD26
RED
LD25
RED
2
1
IC18A
IC18B
LM 339
LM 339
5
7
4
10
2K
R90
R1281KR129
-15V
V
V-
V
V-
Q12
LD28
IC13D
RED
LM 339
2K
13
11
BC 557B
LD29
RED
IC13A
LM 339
5
10
R922KR130
R114
47K
LD30
RED
2
IC13B
LM 339
7
4
1K
R127
R84
100R 1/4W
15V
Q11
BC 557B
LD27
RED
14
IC13C
LM 339
8
9
6
1K
R91
VER040910
11 of
WEN XI ANG
RevisionModel No:
Drawn By:
Sheet
ACL2
ACL2-FP
21-Sep- 2004
ACL2-FP.Sch
A3
Titel
Size
File:
Date:
1
6
1K
IN
LD5
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456
S NGAL OUTPUT 1
SW1
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OUTP UT LEVEL
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3
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C25
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R20
IC1B
TL 064
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0.0068U
1
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TL 064
3
R16
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100P
33P
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Q1
1
C11
6
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A684
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2
R23
20K
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IC2A
4580
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C10
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7
IC2B
4580
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20K
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1
VR3
10KB
ENHANCER
6
R41
2.4K
R19
20K
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2
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R33
47P
C6
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SINGAL IN 1
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100R 1/4W
R81
1.2K
R52
5.1K
R75
15V
RELEASE
1MA
VR1 4
1U
47K
2
R133
TL 064
14
8
4
VR1 3
1KB
12
10
1MA
ATTACK
2.2K
1
RATIO
IC5D
TL 064
IC5C
R96
10M
C37
C21
0.047U
1K
R120
LD2
YEL
7910
SW3
134
-15V
13
TL 064
-15V
R137
1M
AUTO
11
SW -12P
5
6 12
2 8
C35
104P
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IC7E
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BC 547B
R103
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R95
10M
CA3086
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14 3
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IC7B
CA3086
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BC 546B
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BC 546B
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LM 339
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6
14
C27
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IC4C
LM 339
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150R
10
9
R61
3K
10
11
IC4D
LM 339
13
R55
680R
3
R51
1.2K
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THRESHOLD
D5
1N4148
COMP LEVEL 1
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IC6A
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2
D4
TL 064
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1N4148
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R37
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IC6D
TL 064
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13
22K
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R13
1N4148
D1
R11
68K
1N4148
7
47P
C5
TL0 64
5
6
R1
C1
0.47U
R65
R59
8
IC1C
9
COMP OUTPUT 1
7
IC4B
LM339
1
R6
100K
R135
470R
R44
1.5K
C20
C19
VR4
R43
R39
2.2M
0.047U
R57
10KB
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1.5K
0.047U
6.2K
-15V
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1N4148
6.8K
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R117
200K
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RED
LD1
CLOSE
IC5A
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0.47U
D3
1N4148
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IC7D
CA3086
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EXP/GA TE
GAT E ADJ
82K
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10KB
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15V
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R9
4.7K
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47K
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R109
9
IC7C
CA3086
9
6
8 7
R101
10.0K
C33
0.47U/50V
SINGAL IN 1
COMP OUTPUT 1
SINGAL OUTPUT 1
KEY 1
COMP LEVEL 1
KEY 1
IN
LD6
GN
456
SINGAL OUTPUT 2
SW2
SW-6P
OUTPUT LEVEL
C31
R74 1.1 K
1
2
VR1 0
10KB
3
R73
1.1K
C26
R31 20K
R29
IC11B
TL 064
5
C18
0.0068U
1
IC11A
TL 064
3
R25
C13
22U/25V
R24 20K
SINGAL IN 2
100P
33P
20K
3
20K
Q2
1
3
2
C15
R32
22U/25V
1
IC12A
4580
3
2
C14
22U/25V
7
IC12B
4580
5
6
2
VR8
10KB
7
6
R42
2.4K
R28
20K
R27
2
R26
20K
47P
C8
A684
20K
20K
R83
100R 1/4W
1.2K
R54
5.1K
R78
15V
1MA
VR1 6
RELEASE
1U
47K
2
TL 064
14
8
VR1 5
R134
1KB
4
1MA
2.2K
IC15D
12
10
R99
ATTACK
1K
R126
1
RATIO
-15V
TL 064
IC15C
TL 064
10M
C38
C24
0.047U
LD4
YEL
AUTO
7910
11
SW4
134
5
2 8
C36
104P
R100
10M
R106
2.7M
13
2
Q8
R105
2.7M
-15V
R98
10M
6 12
IC17E
IC17A
BC 547B
R138
CA3086
CA3086
1M
SW -12P
C16
22U/25V
2
14 3
5 3
4
IC17B
CA3086
Q6
BC 546B
Q5
BC546B
R36
15K
IC14A
LM 339
5
IC16B
C34
3
2
1
7
TL 064
5
6
R132
470K
2
VR12
3
1K
R125
8
IC16C
9
10
3K
R64
1
TL 064
3
2
R113
47K
13
R112
9
IC17C
CA3086
9
6
8 7
R102
10.0K
6
14
C28
0.22U
IC14C
8
10K
150R
10
LM339
8
9
R63
3K
10
11
IC14D
LM 339
13
R56
680R
3
R53
1.2K
1
THRESHOLD
D11
1N4148
COMP LEVEL 2
1
IC16A
TL 064
3
2
D10
TL 064
IC15B
C4
1N4148
14
R38
24.3K
IC16D
TL 064
12
13
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D8
R14
1N4148
D7
R12
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47P
C7
TL 064
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R3
C3
0.47U
15V
R69
R60
R30
20K
1
ENHANCER
R35
15K
IC11C
9
COMP OUTPUT 2
7
IC14B
LM 339
1
R8
100K
R136
470R
R48
1.5K
C23
C22
VR9
R47
R40
2.2M
0.047U
0.047U
R58
6.2K
-15V
10KB
2
R50
6.8K
1.5K
LD3
D12
1N4148
15V
R118
200K
R116
43K
C32
100P
RED
IC15A
15V
0.47U
D9
1N4148
R68
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IC17D
R108
VR7
10KB
3
15V
2
R10
4.7K
CA3086
8.2K
1110
1
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EXP/GA TE CLOSE
R7
100K
R46
1.8K
VR6
10KB
1
82K
3
2
GATE ADJ
0.47U/50V
SINGAL IN 2
COMP OUTPUT 2
SINGAL OUTPUT 2
KEY 2
COMP LEVEL 2
KEY 2
1 2 3 4 5 6 7 8
12345
CN1
12345
CN2.0-5P-180
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CN2
CN2.0-5P-180
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VER040910
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JY-5030-030G
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12345
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5e
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CON5
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C6
104P
84
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C10
104P
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JY-5030-030G
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11 of
W EN XIANG
Rev isionModel No:
Draw n B y :
Sheet
IC1C
KEY 1
SINGAL IN 1
COMP LEVEL 1
C5
SINGAL OUTPUT 1
10U/50V
33R
33R
100P
SINGAL OUTPUT 1
COMP OUTPUT 1
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COMP OUTPUT 1
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C4
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4580M
KEY 2
ACL2
ACL2-BP
1
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3P2.5
SINGAL OUTPUT 2
COMP OUTPUT 2
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IC3
T H A T2150A
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SINGAL IN 2
COMP LEVEL 2
COMP OUTPUT 2
SINGAL OUTPUT 2
21-Sep-2004
ACL2-BP.Sch
A4
Titel
Size
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Date:
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JY5042-030G
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MIC IN1
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JY-6351G-02-250
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LIN E IN1
5e
1a4d2b
KEY
X10
JY-6351G-02-250
A
PCB : ACL2-FP Bottom Laye
r
yer
PCB : ACL2-FP Bottom Solder Mask
PCB : ACL2-FP TOP La
PCB : ACL2-FP Top overlay
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