Alto FLEX-PLUS Service Manual
Service Manual
Model: FLEX plus
SOUND ENHANCEMENT PROCESSOR
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. Notes
SPECIFICATIONS
1.Specification
AUDIO INPUT
Connectors XLR and 1/4” jack
Type RF filtered , servo balanced input
Impedance 50k ohms balanced, 25k ohms unbalanced
Max . input Level +21dBu balanced and unbalanced
CMRR typ. 40dB, >55 dB @1k hz
AUDIO OUTPUT
Connectors XLR and 1/4” jack
Type Electronically servo-balanced output stage (optional t
ransformer-balanced).Automatic level correction for
unbalanced use(6 dB)
Impedance 60 ohms balanced, 30 ohms unbalanced
Max . output Level +22dBu, +20 dBm balanced and unbalanced
SYSTEM SPECIFICATIONS
Bandwidth 20 hz to 30k hz,,+0/-0.5 dB
Frequency Response 0.35 hz to 200k hz,+0/-3dB
Noise >-110 dBu,unweighted,22 hz to 30k hz
THD 0.002% typ. @ +4 dBu,1k hz, Gain 1
0.002 % typ. @ +20 dBu,1k hz, Gain 1
IMD 0.01 % typ.SMPTE
Crosstalk <-100 dB , 22HZ to 22k hz
BASS PROCESSOR
Type “Dual Mode” Bass Processor
Low Mix variable (0 to 6)
MULTIBAND PROCESSOR
Type “Natural Sonic” processor with VSP (Variable Sound
Processing)
NR Sensitivity variable (0 to 6)
Tune variable (1 to 8k hz)
Process variable ( Enhancer to Exciter)
High Mix variable (0 to 6)
SURROUND SECTION
Surround variable (0 to 6)
FUNCTION SWITCHES AND CONTROLS
Shift Switches the frequency of the Bass Processor berween
“Low” and “Ultra –Low”
Mode Switches the bass sound from “Soft” to “Tight”
Auto NR Activates the noise reduction system
In/Out Activates the relay controlled hard-bypass
Solo Monitors the pure effect signal (Solo funtion)
Surround Activates the surround processor
INDICATORS
Effect 13 LED meter indicates the effect
Function switch LED indiactor for each function switch
Input Level 4 element LED
POWER SUPPLY
AC 95-120 Vac / 60 hz Fuse: 500mA( slow blow)
AC 210-240 Vac / 50 hz Fuse: 315mA( slow blow)
POWER CONSUMPTION
11W
DIMENSIONS
483(W)×194.5(D) ×44(H)mm (19” ×7.7” ×1.7”)
WEIGHT
3.4KG
D
2.Block Diagram
C
B
A
4
321
BYPASS
213
4
CH1 OUTPUT
3c5e1a
SECLECT
RELAY
BALANCE
ADDITION
4d
2b
SOFT/TIGHT
PHONEJACK5 (5-PIN)
BASS
BYPASS
MULTIBAND
213
4
CH2 OUTPUT
3c5e1a
SECLECT
RELAY
BALANCE
ADDITION
4d
2b
SOFT/TIGHT
PHONEJACK5 (5-PIN)
BASS
MULTIBAND
SOLO
LOW/ULTRA-LOW
SOFT
TIGHT
SENSISTIVITY
TUNE PROCESS ADDITION
1
A
4580
3
2
SOLO
LOW/ULTRA-LOW
SOFT
TIGHT
SENSISTIVITY
TUNE PROCESS ADDITION
1
A
4580
3
2
SURROUND
213
4
CH1 INPUT
3c5e1a4d2b
PHONEJACK5 (5-PIN)
213
4
CH2 INPUT
3c5e1a4d2b
1 2 34
PHONEJACK5 (5-PIN)
D
C
B
A
A
3.Schematic Diagram
VER030224
11of
C.C.LIN
RevisionModel No:
Drawn By:
Sheet
ALTO FLEX
R120
100K
C36
100N
1
C12
47P
IC12A
4580
3
2
R41
20K0
6K81
R128
2
1
B10K
VR11
IC12B
4580
5
R126
6K81
1
IC11A
4580
3
IC11B
4580
2
R156
2K20
1
5
3
C10K
VR10A
ALTO : ALTO FLEX FP BOARD
A3
Titel
Size
C3
47u/25VC447u/25V
312
IC21E
LM339
312
IC19E
LM339
11-Jul-2003
Date:
FLEXFP.Sch
File:
-15V+15V
100N
B
-15V
R150
5K62
R118
1u/50V
C50
-15V
2
1
VR8
B10K
R38
20K0
R142
23K7
+15V
+15V
R122
6K81
456
SW8B
P
SW10D
SHIFT
100K
330P
C48
5
1
IC13A
LM13600
R42
234
R144
47K5
7
IC9B
4580
5
6
R132
1K00
1
D10
1N4148
IC10A
4580
3
2
2
3
P
AUTO NR
VR9
C30
100N
7
5
6
C42
R116
100K
C41
2N2
R136
1K00
R135
1K00
R140
47K5
R127
C44
10P
R138
549K
2.2u/25V
C62
R131
1K00
1
A10K
IC10B
4580
R117
100K
2N2
C57
103P
20K0
3
C35
100N
7
6K81
6
3N3
C60
C59
3N3
R21
10K0
47P
C84
2
R20
10K0
7
6
C58
103P
R88
2K20
4
5
VR10B
C10K
6
GRN
9
806R
1u/50V
6
1u/50V
2
C
LD20
GRN
LD21
GRN
LD22
GRN
LD25
GRN
LD26
GRN
LD19
GRN
LD18
2
1
14
IC18C
IC18B
LM339
LM339
8
6
7
R94
1K00
R92
LED10
YEL
456
P
SHIFT
SW9B
P
SHIFT
7
IC22B
4580
5
R84
C87
1
IC23A
4580
3
5
1K50
P
MODE
2K20
100u/25V
R160
6
511R
IC18A
4
LED11
SW7B
7
R161
LM339
11
2K20
R96
RED
456
SW7A
C20
R90
C8
47P
IC8B
C88
5
27K4
13
10
100u/25V
1K50
1
2
R80
4580
100N
IC19D
LM339
R98
P
SOLO
3
5K11
1
14
IC19C
IC19B
LM339
8
9
3K01
123
R26
R78
R13
6
7
4K22
R100
-15V
R17
10K0
C10
R86
R16
10K0
3
C21
100u/25V
SOLO
123
SW9A
20K0
IC8A
4580
C26
100N
8K20
SW10A
SHIFT
10K0
GRN
2
LM339
5
6K04
R146
47P
2K20
R82
2
B10K
VR7
MODE
C23
100u/25V
2
C31
100N
1
2
3
R33
16K5
C52
IC19A
LM339
4
30K1
R148
CH2_OUTPUT
1
IC9A
4580
3
2
5K11
1
3
0.22u/25V
C46
R37
20K0
1
IC22A
4580
C32
100N
3
R36
16K5
10
11
R35
16K5
12
R34
16K5
D
GRN
GRN
GRN
GRN
LD5
LD34
HR
TR6
R48
1K2
+15V
R64
8
7654321
R46
1K2
+15V
R62
200K
R45
1K2
+15V
R61
200K
200K
R59
100K
TR5
R47
1K2
+15V
200K
R63
R58
100K
HR
TR4
13
100K
R57
HR
TR3
R56
100K
10
11
R66
110R
14
8
9
R65
110R
14
9
R50
121R
HR
GR
GR
LD30
LD31
14
IC21C
IC21D
LM339
LM339
8
9
R68
R70
330R
GR
GR
LD27
LD28
13
IC20D
IC20C
LM339
LM339
10
11
R67
R69
330R
LD6
1
13
IC17D
IC17C
LM339
LM339
8
11
R52
SW6B
1
IC21B
6
7
1K3
1
IC20B
6
7
1K3
10
169R
LED7
GRN
456
GR
LD32
LM339
5
R72
1K8
GR
LD29
LM339
5
R71
1K8
6
7
R54
220R
-15V
P
BYPASS
RED
LD2
2
IC21A
LM339
4
R74
6K34
RED
LD1
2
IC20A
LM339
4
R73
6K34
LD15
IC17B
LM339
R104
LED9
123
SW8A
-15V
-15V
GRN
LD16
LD17
2
13
IC17A
IC18D
LM339
LM339
5
4
10
11
R106
330R
GRN
D6
1N4148
+15V
D3
1N4148
+15V
R102
511R
LED8
RED
456
SW10B
AUTO NR
789
SW10C
C38
R112
1K00
D8
1N4148
R110
47K5
D7
1N4148
R109
47K5
C37
R111
1K00
D5
1N4148
R108
47K5
D4
1N4148
R107
47K5
1234567891011
J1
CON12
+15V
CH1_INPUT
R2
301K
+15V
D2
1N4148
R1
301K
+15V
D1
1N4148
+15V
+15V
CH1_OUTPUT
C2
C1
47u/25V
47u/25V
R44
1K2
R60
R43
1K2
R153
CH2_INPUT
-15V
123
SW6A
-15V
123
SW11A
200K
200K
312
IC18E
312
R163
47R
+15V
312
-15V
312
312
312
R151
47R
+15V
3
C89
LM339
IC17E
LM339
IC10C
4580
47u/25V
IC20E
LM339
IC16E
LM339
IC15E
LM339
IC14E
LM339
IC5C
4580
IC22C
4580
IC23C
4580
IC12C
4580
IC11C
4580
IC9C
4580
IC8C
4580
IC7C
4580
IC6C
4580
IC4C
4580
IC3C
4580
IC2C
4580
IC1C
4580
4 8
R164
47R
-15V
C90
47u/25V
4 8
R152
47R
4 8
4 8
4 8
-15V
4 8
4 8
4 8
4 8
4 8
4 8
4 8
1 2 3 4 5 6 78
4 8
4 8
C81
100N
C82
+15V
100N
C79
100N
C80
100N
C77
100N
C78
100N
C75
100N
C76
100N
C73
100N
C74
100N
C71
100N
C72
100N
C69
100N
C70
100N
C67
100N
C68
100N
C65
100N
C66
100N
C63
100N
C64
100N
R119
100K
C34
100N
1
C11
47P
IC7A
4580
3
2
R39
20K0
1
B10K
PROCESS
6K81
IC6A
4580
TUNE
2
2K20
1
VR5A
C10K
A
7
LD12
GRN
LD13
GRN
LD14
GRN
LD23
GRN
LD24
GRN
GRN
GRN
GRN
GRN
GRN
LD3
LD4
LD7
6
BYPASS
C13
R8
C14
IC14B
LM339
R103
LED5
456
SW3B
100u/25V
IC2B
R11
10K0
10K0
C17
100u/25V
R23
20K0
R75
8K20
100u/25V
CH2_INPUT
LD8
2
14
IC14A
IC15C
LM339
5
330R
GR
4580
2
2
8
9
4
R105
511R
LED3
456
P
SW2B
AUTO NR
C7
47P
R12
10K0
R9
10K0
2
3
B1K
VR1
1
IC2A
4580
C25
100N
3
R24
20K0
1
IC1A
4580
3
R7
10K0
R76
8K20
C15
100u/25V
CH1_INPUT
LD33
HR
TR2
1
13
14
IC14D
IC14C
LM339
LM339
R55
100K
HR
TR1
R154
100K
12
-15V
CH2_OUTPUT
D
-15V
BYPASS
-15V
BYPASS
LED1
456
SW1B
R49
RED
8
9
121R
R5
123
SW1A
SURROUND
P
SURROUND
10K0
11
R51
SW11B
C5
47P
10
169R
GRN
LED2
456
R4
7
R53
220R
-15V
P
7
5
6
10K0
R22
20K0
R3
10K0
GRN
LD11
LD10
LM339
SOLO
7
R93
1K00
LED4
123
SW5A
789
SW5C
IC1B
4580
GRN
2
1
IC15B
LM339
6
R91
RED
C85
C
5
1K50
SHIFT
P
SHIFT
R83
2K20
100u/25V
R157
511R
7
6
R158
IC15A
4
LED6
456
SW4B
IC23B
5
27K4
14
IC16C
LM339
LM339
8
9
2K20
R95
R97
YEL
P
MODE
SW2A
100u/25V
C16
R89
1K50
1
C6
47P
3
2
R79
5K11
C86
100N
4580
1
13
IC16D
IC16B
LM339
6
7
10
11
3K01
4K22
R99
-15V
C9
R15
10K0
R14
10K0
3
123
C18
100u/25V
SOLO
123
SW4A
R25
20K0
IC3A
4580
C24
100N
R77
8K20
P
SW5D
SHIFT
R6
10K0
LD9
13
IC15D
LM339
10
11
R101
806R
RED
P
100u/25V
C19
7
5
6
R10
10K0
1
GRN
-15V+15V
C51
2
IC16A
LM339
5
4
6K04
R145
CH1_OUTPUT
1
47P
2
R81
5K11
R85
2K20
2
1
B10K
VR2
LOW MIX
MODE
C22
100u/25V
7
5
6
C28
100N
R30
R29
10
11
12
R28
16K5
R27
16K5
100N
LM339
30K1
R147
IC4A
4580
3
2
3
VR3
C45
0.22u/25V
R31
20K0
IC3B
4580
C29
100N
16K5
4
5
16K5
6
+15V
C49
1u/50V
-15V
1
B10K
HIGH MIX
R32
20K0
R141
23K7
+15V
+15V
R121
6K81
123
SW3A
P
SW5B
SHIFT
B
89
IC13C
LM13600
6 11
-15V
R149
10
16
13
R143
47K5
7
5
6
D9
1N4148
7
5
3
AUTO NR
C27
100N
2
R113
100K
5K62
-15V
R115
100K
C47
330P
12
IC13B
LM13600
15
14
R134
R133
IC4B
4580
R139
47K5
R130
1K00
IC5B
4580
C43
10P
R137
549K
6
VR4
1
3
R129
1K00
2
A10K
1
IC5A
4580
NR SENSITIVITY
R114
100K
C40
2N2
C39
2N2
+15V
1
2
J2
CON2
R162
1K
R40
1K00
1K00
R124
C61
2.2u/25V
5
C53
103P
20K0
R125
6K81
2
3
VR6
C33
100N
7
IC7B
6K81
C83
47P
R87
2K20
4
VR5B
6
4580
5
6
R123
C56
3N3
3N3
C55
1
R19
10K0
3
2
R18
10K0
7
IC6B
4580
R155
5
6
C54
103P
C10K
D
8
C
B
A
VER030120
11of
C.C.LIN
RevisionModel No:
Drawn By:
Sheet
CN5
CN-BAL-MALE
PJ4
213
4
3c5e1a
4d
PHONEJACK5 (5-PIN)
2b
CN4
CN-BAL-MALE
PJ2
213
4
3c5e1a
4d
PHONEJACK5 (5-PIN)
2b
ALTO FLEX
BR
D6
R41
+15V
100R
CH1_OUT-
CH1_IN-
C28
470P
7654321
1N4148
RL2
RELAY-2-24
CH1_OUT-
CH1_OUT+
TR2
-15V
R35
33K
CH1_IN+
CH1_CTL
CH1_OUT+
C27
470P
+15V
R40
100R
CH2_IN-
CH2_OUT-
C26
470P
D5
1N4148
RL1
RELAY-2-24
CH2_OUT-
CH2_OUT+
BR
TR1
11-Jul-2003
-15V
ALTO : ALTO FLEX RP BOARD
1234567891011
R34
33K
CH2_IN+
CH2_CTL
J1
+15V
CH1_CTL
CH1_INPUT
CH1_OUTPUT
CH2_OUT+
C25
470P
12
CON12
-15V
CH2_CTL
CH2_INPUT
CH2_OUTPUT
Titel
C12
10U/50V
C10
104P
C8
104P
FLEXRP.Sch
A4
Size
File:
Date:
C11
10U/50V
C9
104P
C7
104P
C6
104P
C5
R3
R4
R5
0R
R33
60R4
1
IC5A
4580
R21
3K16
R27
R39
6K04
2
R15
10K
4K53
3
R37
2K67
C22
R29
47u/25V
CH1_OUTPUT
CH1_INPUT
7
3K24
R26
4K53
0R
R32
60R4
7
IC5B
4580
C24
R23
5K76
5
6
R20
3K16
R17
10K0
10P
R38
6K04
0R
R31
60R4
1
IC3A
4580
R24
4K53
R28
R19
C21
3K16
47u/25V
3K24
CH2_OUTPUT
CH2_INPUT
1
R25
4K53
3
2
R10
10K
R36
2K67
R2
0R
R30
60R4
7
IC3B
4580
C23
R22
5K76
5
6
R16
R18
3K16
10K0
10P
+15V
+15V
C4
1000u/25VC31000u/25V
104P
IC5C
4580
4 8
IC4C
4580
4 8
-15V
IC3C
4580
4 8
-15V
IC2
IC4A
3
R6
10K
3c5e1a4d2b
PJ1
4580
R8
10K
C17
47P
C14
100P
C13
100P
PHONEJACK5 (5-PIN)
B
IC4B
CN-BAL-FEMALE
5
C19
R11
10K
C15
3c5e1a4d2b
PJ3
4580
R13
10K
C18
47P
C16
100P
100P
PHONEJACK5 (5-PIN)
C
R14
47P
C20
10K
6
R12
10K
CH1_IN-
CH1_IN+
213
4
CN3
D
47P
R9
10K
2
R7
10K
CH2_IN-
CH2_IN+
213
4
CN2
CN-BAL-FEMALE
7815
D4
D2
1
K
A
2
CN1
C2
1000u/35VC11000u/35V
1N4002
1N4002
123
A
IC1
7915
D3
1N4002
D1
1N4002
CON3
R1
TP1
1 2 3 4 5 6 78
0R
TP-2
PCB：FLEXFP Top Layer
4.Printed Circuit Board
PCB：FLEXFP Top Solder Mask
PCB：FLEXFP Bottom Layer
PCB：FLEXFP Bottom Solder Mask
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