Alto PBM4 Service Manual

MODEL: PS 4LA

MODEL: PBM4

www.altoproaudio.com

Version 2.0

CONTENT

1

1. Function Introduction…………………………………………………………….2

2. Specification……………………………………………………………………….2

3. Block Diagram……………………………………………………………………..3

4. Schematic Diagram……………………………………………………………….4

5. Wiring Diagram………………………………………………………… …………9

6. PCB Layout……………………………………………………………... ………..10

7. Test Procedure…………………………………………………………………....17

8. Exploded Views & Mechanical Parts List…………………………………….25

9. BOM…………………………………………………………………………………29

The PBM4 is professional monitor. It is packed with some key features. For example: there is four MIC/LINE

Microphone Input

Electronically balanced, discrete input

Frequency response

10Hz to 55kHz, +/- 3dB

Distortion(THD&N)

0.05% at +4dBu, 1kHz

Gain

30dB

SNR(Signal to Noise Ratio)

>94dB

Line input

Electronically balanced

Frequency response

10Hz to 55kHz, +/- 3dB

Frequency response

0.05% at +4dBu, 1kHz

Gain

10dB

Microphone Input

1.4kOhm

Channel Insert return

2.5kOhm

All other inputs

10kOhm or greater

Tape out

1kOhm

All other outputs

120Ohm

Hi shelving

+/-15dB@12kHz

Low shelving

+/-15dB@80Hz

DSP Section

A/D and D/A converters

24bit

DSP resolution

24bit

Type of effects

REV+DELAY, and REV+CHORUS

REVERBS, Stereo DELAY, Chorus

Presets

16

Controls

16-position PRESET selector

CLIP LED

MUTE SWITCH with LED indicator

Noise(Bus noise)

Fader 0 dB, channels muted: -85dBr (ref.:

Fader 0 dB, all input channels assigned and

UNITY gain: -81dBr(ref.: +4dBu)

M max out ONITOR

+22dBu unbalanced, 1/4"jacks

FX Sends max out

+22dBu

Output Power

150W RMS (Nominal power)

Frequency Response

25HZ-20KHZ

Output Impedance

8 ohm

Dimensions

216.5

×

143.5

×

152.5mm(L

×W×

H)(8.5"

×

5.6"×6")

Net Weight

9.5kg

Shipping Weight

11.34 kg

Volume

2.8CFT

1. Function Introduction

2. Specification

2

inputs which provided with ultra low noise microphone pre-amplifiers and phantom power at +15V, each of
them features a 2-band equalizer, one AUX send and level control. FX MAIN/MONITOR outputs,16-position
multi-effect and soon.

Input channels

Impedance

Equalization

Main Mix Section

Amplifier Section

Physical

D

3. Block Diagram

3

8

C

B

A

VER050105

11of

SHUNG LIN

RevisionModel No:

OUTPUT

AUX SEND2

T

RSS

7654321

1

2

TRS

POWER AMPLIFIER

ALTO PBM4

BLOCK DIAGRAM

( 4 POINT )

DFX SEND

DFX(DSP)

MAIN LEVEL

16KHz

6.3KHz

2.5KHz

1KHz

400Hz

160Hz

7-STAGE EQ

63Hz

MAIN BUS

TAPE OUT

2-TRACK

TAPE IN

LEVEL

2TK IN

Drawn By:

TRS

Sheet

MONITOR OUT

PBM4-MX

PBM4-MX BLOCK AND LEVEL DIAGRAM

13-Jan-2005

PBM4MX BLOCK-final.Sch

A2

Titel

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MONITOR LEVEL

MAIN BUS

DFX (DSP)

MAIN-BUSMAIN BUS

MAIN BUS

AUX/DFX RET

T

RSRN

TN

3c5e1a4d2b

FX RETURN

DSP BOARD

PRESETS

MUTE

DSP FOOTSWITCH

OFF

PHANTOM

ON

+15V

[-6dB]

DFX SEND

[0dB]

LEVEL

[-10dB]

HA

LOW HI

[10dB]

213

CH INPUT

LOW-Z

HI-Z

[-40/-20dB]

[-30/-10dB]

2-STAGE EQ

(CH1-4)

1 2 3 4 5 6 78

D

C

B

A

100NF

4. Schematic Diagram

4

2.2K

2.2K

R61KR2

47UF/25V

A

PING LU TANG

2004/11/01

PBM4

Number RevisionSize

C

Title

Date: 3-Feb-2005 Sheet of

File: PBM4 Drawn By:

33K

OUT2

SP2

GND

SP2

SPEAKER

D

654321

GND

C41

470UF/35V

C31

GND

C37

1000UF/35V

C35

6800UF/50V

D4

BU10--04

470UF/35V

3

OUT

GND

1

2

IN4004

3

C30

1000UF/35V

C13

6800UF/50V

D3

IN4004

IN

U3

7915

2

R9

200O

+15V

3

Vout

D6

IN4004

Vin

U6

7815

1

R3

95O

+VA

D5

IN4004

2

BR

1

4

C36

0.1UF/275V

C

INPUT-

INPUT+

GND

C20

1UF/50V

47UF/50V

GND

100NF

-VA

R15

C2

C6

C5

61.9K

100NF

C1

100NF

R8

100UF/50V

100UF/50V

-15V

C18

R5

2.2K
C15

2.6V

NC

11

+VIN

10

-VIN
9

MUTE

8

GND

7

NC
V+
V-

U1

LM3886

OUT
NC

-VA

V+

GND

6
5
4
3
2
1

+VA+VA

B

INPUT+

INPUT-

-15V

GND

+15V

GND

SP2

OUT2

SP1

OUT1

10

CN2

R13

47K

GND

100

GND

C19

34.9V

R4

100NF

47UF/25V

34.7V

1K

R1

OUT1

SP1

SP1

330UF/16V

D2

IN4737D1IN4737

R19

61.9K

33K

GND

SPEAKER

27V

U2

27V

LM3886

35V

Q1

2N5551

C10

C9

123456789

CON10

PC250

PC250

PC250

3.48K

R18

NC
+VIN

-VIN
MUTE
GND
NC
V+
V­OUT
NC
V+

3.48K

35V

C14

20V

11

10
9
8
7
6
5
4
3
2
1

100UF/50V

GND

R7

C17

100NF

2.6V

R7

-VA

C4

100NF

C12

C3

100UF/50V

C11

C7

100NF

C8

100UF/50V

GND

R16

GND

T1

S1

SW SPST

D

AC

LAMP NEON

TRANS5

F?

FUSE1

GND

1 2 3 4 5 6

C

B

A

7654321

5

+PHANTOM

R2

R1

6K8

CGND

CGND

6K8

R3
6K8

R7

10K

R10

10K

+PHANTOM

R5
6K8

+PHANTOM

C1

47U/50V

C7

47U/25V

C8

47U/25V

C2

47U/50V

C3

47U/50V

C10

47U/25V

C11

47U/25V

C4

47U/50V

R56

2K2

R57

22K

R58

22K

R59

2K2

CGND

R60

2K2

R61

22K

R62

22K

R63

2K2

1
2
3
4
5
6

CN1

CN2.0-6P-180

CN2

CN2.0-6P

1
2
3
4
5
6

R34
10K

R38
10K

C22

22P

R8

10K

U1A

4580M

2

3

C21

22P

1

C9

47U/25V

R74

1K

C25

22P

R11

10K

U3A

4580M

2

3

C24

22P

1

C12

47U/25V

R75

1K

C23

22P

EQ HI

10KHZ

R80

3K

6

5

U1B
4580M

C27

22P

7

C142

47U/25V

100Hz

EQ HI

10KHZ

R81

3K

6

5

U3B
4580M

7

C143

47U/25V

J1

JY5042-030G

D

CH1 INPUT

1
3
2
4

CH1 LINE

J2

SCJ-0658-1-Y

JY5042-030G

5e

1a
2b
4d
3c

J3

1
3
2
4

CH2 INPUT

CH2 LINE

C

J4

SCJ-0658-1-Y

5e

1a
2b
4d
3c

LOW

LOW

100Hz

R85
8K2

R177
2K2

R88
8K2

R178
2K2

R97
3K9

R99
3K9

R86
8K2

R89
8K2

VR1

B50K

VR5

B50K

C39
4N7(M)

VR2
B50K

C43

4N7(M)

C40
4N7(M)

VR6
B50K

C44

4N7(M)

R98
3K9

R87
8K2

R101
3K9

R90
8K2

C47

47U/25V

C51

47U/25V

LEVEL

C49

47U/25V

VR4
W50K

R35

22K

R112
8K2

C67

22P

R116

C50

U2A

4580M

36K

1

47U/25V

2

3

C66
22P

R105

1M

C48

U2B
4580M

47U/25V

7

6

5

J11

(PRE) POST

LEVEL

C53

47U/25V

VR8
W50K

R39

22K

R113
8K2

C70

22P

R117

C55

U4A

4580M

36K

1

47U/25V

2

3

C68
22P

R106

1M

C52

U4B
4580M

47U/25V

7

6

5

J12

(PRE) POST

PBM4 (1/4)

R9

R121

5K1

R122

5K1

10K

R12

10K

AUX-POST

VR3

W50K

AUX-POST

VR7

W50K

MAIN-BUS

FX SEND

MAIN-BUS

FX SEND

8

D

C

R6

R4

6K8

CGND

CGND

6K8

R42
6K8

R13

10K

R166

10K

+PHANTOM

R165
6K8

C5

47U/50V

C13

47U/25V

C14

47U/25V

C6

47U/50V

C138

47U/50V

C140

47U/25V

C141

47U/25V

C139

47U/50V

R64

2K2

R67

22K

R68

22K

R69

2K2

R170

2K2

R171

22K

R172

22K

R173

2K2

CGND

1
2
3
4
5
6

CN3

CN2.0-6P-180

CN4

CN2.0-6P

1
2
3
4
5
6

R43
10K

R126

10K

C26

22P

R14

10K

U5A

4580M

2

3

C29

22P

1

C15

47U/25V

R76

1K

C30

22P

R44

10K

U7A

4580M

2

3

C32

22P

1

C16

47U/25V

R77

1K

C28

22P

EQ HI

10KHZ

R82

3K

6

5

U5B
4580M

C31

22P

7

C144

47U/25V

100Hz

EQ HI
10KHZ

R83

3K

6

5

U7B
4580M

7

C145

47U/25V

100Hz

J5

JY5042-030G

1
3
2
4

CH3 INPUT

CH3 LINE

J6

SCJ-0658-1-Y

B

JY5042-030G

J17

5e

1a
2b
4d
3c

1
3
2
4

CH4 INPUT

CH4 LINE

J18

SCJ-0658-1-Y

5e

1a
2b
4d
3c

LOW

LOW

R91
8K2

R179
2K2

R94
8K2

R180
2K2

R100
3K9

R103
3K9

R92
8K2

R95
8K2

VR9

B50K

VR13

B50K

C41
4N7(M)

VR10
B50K

C45

4N7(M)

C42
4N7(M)

VR14
B50K

C46

4N7(M)

R102
3K9

R93
8K2

R104
3K9

R96
8K2

C56

47U/25V

C57

47U/25V

LEVEL

LEVEL

C54

47U/25V

VR12
W50K

R45

22K

C60

47U/25V

VR16
W50K

R48

22K

R114
8K2

R115
8K2

2

3

2

3

C71

22P

R118
36K

1

U6A

4580M

J13

(PRE) POST

C73

22P

R119
36K

1

U8A

4580M

J14

C61

47U/25V

C62

47U/25V

R123

5K1

R124

5K1

R15

10K

R16

10K

AUX-POST

VR11

W50K

AUX-POST

VR15

W50K

MAIN-BUS

FX SEND

B

MAIN-BUS

FX SEND

C69
22P

R107

1M

C58

U6B
4580M

C72
22P

R108

1M

U8B
4580M

47U/25V

7

C59

47U/25V

7

6

5

6

5

(PRE) POST

A

7 BAND EQ
PBM4-MX_4.SCH

1 2 3 4 5 6 78

MAIN SECTION
PBM4-MX_2.SCH

DSP SECTION
PBM4-MX_3.SCH

+VCC

-VCC

U1C

4580M

C81

84

100N

U2C

4580M

C82
100N

C83

84

100N

U3C

4580M

C84
100N

C85

84

100N

C86
100N

84

U4C

4580M

C87
100N

C88
100N

84

U5C

4580M

C89
100N

C90
100N

84

U6C

4580M

C91
100N

C92
100N

84

U7C

4580M

C93
100N

C94
100N

84

U8C

4580M

C95
100N

C96
100N

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PBM4 INPUT SECTION

PBM4

8-Jan-2005
PBM4-MX_1.Sch

Sheet
Drawn By:

RevisionModel No:

SHUNG LIN

A

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41of

7654321

6

8

7 BAND EQ

C33 22P

R129

1K5

D

MAIN-BUS

2

3

U9A

4580M

1

C17

47U/25V

R71

5K6

R17
6K8

C118

10P

R130

39K
U19B

6

5

4580M

C35 22P

R135

C64

47U/25V

12K

U10A
4580M

1

R148

7K5

C19

EFFECT_IN

47U/25V

C36

22P

C

FX SEND

2

3

MONITOR OUT

VR21

R147

MAIN-OUT

B

J7

RCA4-SCP687

TAPE IN

27K

TAPE OUT

1 4

W50K

R65

2K2

2 5

R66

2K2

3

CGND

A

1 2 3 4 5 6 78

6

CGND

C76
100P

C77
100P

CGND

+PHANTOM

C74

47U/25V

C75

47U/25V

CGND

6

5

R46

22K

R47

22K

470R 1/2W

C146
470uF/50V

R181

U12B

4580M

CGND

7

CN2.0-6P-180

CGND

2

3

7

R120

36K

C65

47U/25V

1
2
3
4
5
6

CN10

SW1

3

2

1

6P-SL2020

C78

22P

R19

22K

U19A

4580M

MON_EQ_OOL_1MON_EQ_OOL_2

R53

22K

R54

22K

R52
22K

CN11

CN2.0-6P

1
2
3
4
5
6

MON_EQ_SOURCE

1

R137

5K6

R128

47K

R138

5K6

R127
47K

C134

10P

6

5

VR17
W50K

R70

22K

R136

39K

U20B

4580M

R21 10K

2

3

C119
56P

R22

10K

6

5

C120
56P

MAIN-OUT

R167

10K

R18
6K8

2

3

7

U13A

4580M

U13B

4580M

C125

100N

MAIN-BUS

C79

R125

5K6

U20A

4580M

100R 1/4W

1

100R 1/4W

7

+VCC

R32

100R 1/4W

22P

1

R149

R150

EFFECT_IN

RTN_L
RTN_R

FOOTSW

C135

100uF/25V

GND1

C18

R20

680R

47U/25V

VR20
B50K

MAIN LEVEL

C20

MAIN-OUT

47U/25V

CN5

CN2.0-8P-180

1
2
3
4
5
6
7
8

1
2
3

CN12

TO AMPLIFIER BOARD

TP1

C122
4U7/63V(NP)

CN2.5-3P-180

OPERATING

+VCC

D9
GR

R151
3K9/0805

R174
8K2

R51

100K

R78

1K

1
2
3
4
5
6
7
8

CN6

CN2.0-8P

R49

2K7

D1

RLS4148

2

3

6

5

R139

100K

R109

1M

4580M

R79

1K

U11A

U11B
4580M

CGND

CGND

CGND

2

3

U12A

4580M

30dB

10dB

1

0dB

10dB

R141

7

680R

J8

3c
4d
2b

1a

5e

SCJ-0658-1-Y

MONITOR OUT

SCJ-0658-1-Y

3c
4d
2b

1a

5e

J10

SCJ-0658-1-Y

3c
4d
2b

1a

5e

J16

3c
4d
2b

1a

5e

SCJ-0658-1-Y

FX RETURN

J19

3c
4d
2b

1a

5e

SCJ-0658-1-Y

FOOTSW

C34

22P

J9

R131

22K

C63

1

47U/25V

MAIN-OUT

R50
22K

D5

MAIN VMETER

3mm

GR

D6

3mm

GR

D7

3mm

YEL

D8

3mm

RED

R146
180R

OUT-1

MAIN POWER OUTPUT
(MIN. LOAD 8OHMS)

OUT-2

3c
4d
2b
1a

5e

SCJ-0658-1-Y

FX SEND

CGND

J15

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PBM4 (2/4)

84

U19C

C80
100N

4580M

C115
100N

84

C97
100N

U11C

4580M

84

U9C

C98
100N

C99
100N

4580M

C100
100N

84

U12C

C103
100N

4580M

C104
100N

PBM4 MAIN & OUTPUT SECTION

PBM4

8-Jan-2005

PBM4-MX_2.Sch

84

U20C

4580M

R133

22R 1/4W

R134

22R 1/4W

84

U10C

4580M

84

U13C

4580M

CN9

2.5-5P

1
2
3
4
5

Sheet
Drawn By:

+VCC

-VCC

+VCC

C116
100N

C117
100N

-VCC

+VCC

C101
100N

C102
100N

-VCC

+VCC

C105
100N

C106
100N

-VCC

+VCC

-VCC

MAIN-OUT

RevisionModel No:

SHUNG LIN

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C

B

A

01

42of

7654321

7

PBM4 (3/4)

8

R25

10K

U10B

6

5

4580M

D3
RLS4148

U14B

4580M

C37
22P

R73
2K2

C123

3N3

R140
100K

1N5

7

7

C127

C124

47U/25V

MUTE

R26
10K

R27
10K

3

R72
2K2

D2

RLS4148

D4

RLS4148

2

3

TR1
J176

D1G

2

S

C38
22P

R28
10K

U14A

4580M

R153

15K

1

VR22

W50K

R132

AUX/DFX RET

56K

R154

12K

DSP-IN

MAIN-BUS

MUTE

R156

1M

C128
100N

PIN1 CONN

DSP-OUT-L
DSP-OUT-R

DSP-IN

DSP-M-OUT

D10

RLS4148

+5V

U16A
NE555

OUT3RS

CTR5DS

TG

TH

7

CN8

12
34
56
78

910
1112
1314
1516

HEADER 8X2

+5V

R110
1M

4

2

6

GND

U18C

74HC14

56

R142

680R

R143

680R

U18B

74HC14

R144

680R

+5V

R145
680R

34

DSP-M-OUT

SW2

BINARY 4BIT ENCODER

1

1

2

2

3

4

4

8

COM

PROGRAM

D

C

+VCC

-VCC

R55
22K

R152

10R

C121
56P

C126
47uF/50V

R155
220K

6

5

RTN_L

D

C

DSP-OUT-L

DSP-OUT-R

RTN_R

EFFECT_IN

R163

27K
R23

10K

R24

10K
R164

27K

R175
10K

R176
22K

C107
100N

R29

10K

R111

1M

7

C111
100N

C112
100N

R158

2M2

U15B
LM393

+VCC

MUTE(GLOW)

PEAK(FLICKER)

B

A

1 2 3 4 5 6 78

R157
4K7

-VCC

+VCC

84

U14C

4580M

-VCC

LD1
RED

1

C129
1U/50V

U15A

LM393

C109
100N

C110
100N

3

2

84

U15C

4580M

5

6

R84
6K8

R159
220R

R161
820K

D11

RLS4148

D12

RLS4148

6

7

U17A
74HC109

Q

Q

S5R

CLK

1

CLK

15

81

U16B

J

K

C130
220N

14

12

13

DGND

U17C

74HC109

DGND

168

+5V

DGND

C113

100N

R30
10K

C131
100N

U18G

74HC14

147

U18A
74HC14

C114

100N

+5V

12

DGND

+5V

R31
10K

C132
1U/50V

C133
10UF/25V

R162

R160

220R

TR2
7805

DSP MUTE

SW3A

PS-22E85L-2

2

5

1

3

4

6

FOOTSW

SW3B
PS-22E85L-2

R33

82R 1/4W

C148
220U/16V

B

+VCC

C147
10UF/25V

C108

100N

DGND

U17B
74HC109

10

Q

D13

9

Q

S11R

RLS4148

U18E

10 11

74HC14

74HC14

2

J

4

3

K

8 9

74HC14

12 13

U18D

U18F

DGND

NE555

0R0

DGND

DGND

DGND

Titel

Size

A3

Date:
File:

PBM4 DSP SECTION

PBM4

8-Jan-2005

PBM4-MX_3.Sch

Sheet
Drawn By:

RevisionModel No:

SHUNG LIN

A

01

43of

7654321

8

8

50Hz FREQUENCY BAND

U9B

7

4580M

RF1_3

5

6

CF1_1
220N

RF1_4

15K

MON_EQ_SOURCE

RF1_1

15K

MON_EQ_OOL_1

RF1_7A

W100K

RF1_5

D

MON_EQ_OOL_2

18K

15K

RF1_7B

W100K

CF1_2

RF1_2

5K6

220N

160Hz FREQUENCY BAND

UF2A

1

4580V

RF2_3

8K2

CF2_2
220N

3

2

CF2_1
220N

RF2_4

8K2

MON_EQ_SOURCE

RF2_1

8K2

RF2_2

1K2

MON_EQ_OOL_1

RF2_7A

W100K

MON_EQ_OOL_2

C

RF2_5

18K

RF2_7B

W100K

1KHz FREQUENCY BAND

UF3A

MON_EQ_OOL_1

RF5_7A

W100K

MON_EQ_OOL_2

RF5_5

18K

4

4580V

1

RF5_3

47K

RF5_7B

5

W100K

CF5_2
10N

6

2.5Hz FREQUENCY BAND

UF3B

MON_EQ_OOL_1

RF6_7A

W100K

MON_EQ_OOL_2

RF6_5

18K

RF6_7B
W100K

4580V

7

RF6_3

22K

CF6_2
10N

3

2

RF5_4
47K

5

6

RF6_4

22K

CF5_1
10N

CF6_1
10N

RF5_1

47K

RF5_2
2K7

RF6_1

22K

RF6_2
1K

PBM4 (4/4)

MON_EQ_SOURCE

D

MON_EQ_SOURCE

C

400Hz FREQUENCY BAND

UF2B

7

4580V

RF4_3

39K

CF4_2
33N

5

6

CF4_1
33N

RF4_4

39K

MON_EQ_SOURCE

RF4_1

39K

RF4_2

1K8

MON_EQ_OOL_1

RF4_7A

W100K

MON_EQ_OOL_2

RF4_5

18K

RF4_7B

B

W100K

6.3KHz FREQUENCY BAND

UF4A

MON_EQ_OOL_1

RF8_7A

W100K

MON_EQ_OOL_2

RF8_5

18K

RF8_7B
W100K

4580V

1

RF8_3

100K

CF8_2
1N

3

2

CF8_1
1N

RF8_4

100K

RF8_1

100K

RF8_2
3K3

MON_EQ_SOURCE

B

16KHz FREQUENCY BAND

UF4B

84

UF2C

4580V

84

UF3C

4580V

84

UF4C

4580V

C136
100N

C137
100N

+VCC

-VCC

MON_EQ_OOL_1

RF9_7A

W100K

MON_EQ_OOL_2

RF9_5

18K

RF9_7B
W100K

7

4580V

RF9_3

27K

CF9_2

1N

5

6

CF9_1
1N

RF9_4

27K

MON_EQ_SOURCE

RF9_1

27K

RF9_2
2K2

A

Titel

Size

A3

1 2 3 4 5 6 78

Date:
File:

8-Jan-2005

PBM4-MX_4.Sch

PBM4 7 BANE EQ

PBM4

Sheet
Drawn By:

RevisionModel No:

01

44of

SHUNG LIN

A

D

5. Wiring Diagram

9

Amp module

C

B

A

Number RevisionSize

PING LU TANG

B

Date: 3-Feb-2005 Sheet of

File: PBM4 Drawn By:

654321

PBM4 WIRING DIAGRAM

Title

MX

PBM4 WIRING DIAGRAM

IN/OUT

2

D1

1

T1

F1

S1

BRIDGE1

3

4

TRANS4

FUSE1

SW-SPST

AC 230V

1 2 3 4 5 6

D

C

B

A

0

6. PCB Layout

(1) PCB: PBM4-MX BOTTOM LAYER

PCB: PBM4-MX BOTTOM LAYER

10

0

0

0

00

00 0

000

0000

0

0