Alto HPA6 Schematic

Service Manual

Model: HPA6

6-Channel HEADPHONE AMPLIFIER

www.altoproaudio.com

Version: 1.1

CONTENTS

1. Specification…………………………………………. 2

2. Block Diagram………………………….…………… 1

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

4. Printed Circuit Board………………………………. 8

5. Wiring Diagram…………………………………..… . 1

6. Test Procedure………………………………….…… 2

7. Electrical Parts List………………………………… 10

8. Exploded Views………………………………..……. 1

9. Notes…………………………………………….……

Input

1.Specifications

MAIN input

Connectors XLR and 1/4” jack Type RF filtered, servo balanced input Impedance 50k Ohms balanced, 25k Ohms unbalanced Max.Input level +21 dBu balanced and unbalanced (unity gain) CMRR typ.40 dB,>55 dB @ 1kHz

AUX IN and DIRECT IN input

Connectors 1/4” jack (tip=left, ring=right, sleeve=ground) Type unbalanced Impedance 25k Ohms unbalanced Max.Input level +21 dBu unbalanced (unity gain) CMRR typ.40 dB,>55 dB @ 1kHz

Output

Connectors XLR and 1/4” jack Type balanced/unbalanced Impedance dependent on input balanced Max.Input level +21 dBu balanced and unbalanced

SYSTEM SPECIFICATIONS

Frequency response 10Hz to 50kHz,+/-3dB Noise >90dB,unweighted,22Hz to 22kHz THD 0.005%typ.@+4dBu, 1kHz, Gain 1

POWER AMPLIFIER

Max.output power +21dBm Min.output impedance 100Ohms Max.gain +20dB

FUNCTION CONTROLS

Input level variable Balanced per channel mix between aux and main signal Output level per channel variable

FUNCTION SWITCHES

Left mute mutes the left signal of this channel Right mute mutes the right signal of this channel Mode switches channel to mono/stereo

INDICATORS

Input level 8-digit LED display:-24/-18/-12/-

6/0/+6/+12/+18dBu

Output level 4-digit LED display:-24/0/+12/CLIP

POWER SUPPLY

Mains voltages USA/Canada 120V~,60Hz

Power consumption 20 WATTS Fuse 100-120V~:T 315mAH

U.K./Australia 240V~,50Hz Europe 230V~,50Hz General exprot model 95-120~,210-240~,50-60Hz

200-240V~:T 160mAH

Mains connection Standard IEC receptacle

PHYSICAL

Dimension(W*H*D) 483*44*217mm Net weight approx.2.9kg

D

2.Block Diagram

C

B

A

4321

AC 110/220V INPUT

LEFT

MASTER OUTPUT

213

4 X5

X6

3c5e1a

4d

POWER SUPPLY

VOLTAGE REGULATOR

-15VDC

+15VDC

RIGHT

SIGNAL

MASTER OUTPUT

PRESENT

G

213

2b

4 X7

X8

3c5e1a

4d

2b

SIGNAL

SENSE

PRESENT

G

SIGNAL

SENSE

CH1 REAR OUTPUT1

X9

3c5e1a

4d

2b

CH1 FRONT OUTPUT

LEFT

CH1 REAR OUTPUT2

X10

3c5e1a

4d

2b

X3

3c5e1a

4d

2b

RIGHT

~ ~

TO STAGES 2-6

Block Diagram

213

X1

3c5e1a4d2b

X2

MASTER LEVEL

213

X3

3c5e1a4d2b

X4

3c5e1a4d2b

1

2

3

1

2

3

1

2

3

L-MUTE

R-MUTE

MONO/STEREO

HEADPHONE LEVEL

BALANCED

1 2 3 4

3c5e1a4d2b

D

LEFT

MASTER INPUT

RIGHT

MASTER INPUT

X1

C

DIRECT IN

B

X2

AUX INPUT

A

87654321

3.Schematic Diagram

TIP : L-CHANNEL

RING:R-CHANNEL

OUT1/R

D

3c5e1a4d2b

OUT 1

X3

SCJ-0658-1-Y

GND2

OUT1/L

TIP : R-CHANNEL

RING:L-CHANNEL

OUT2/R

3c5e1a4d2b

C

OUT 2

X5

SCJ-0658-1-Y

GND2

OUT2/L

TIP : R-CHANNEL

RING:L-CHANNEL

OUT3/R

3c5e1a4d2b

B

OUT 3

X7

SCJ-0658-1-Y

GND2

OUT3/L

HPA6-CH4,5,6

HPA6FP-2.SCH

A

31 of

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Sheet

C4

47P

R3

R222

C19

(VOLUME CTRL)

VR3B

A100K

R74

10K0

R43

15K0

C17

220uF/4V

R29

R30

10K0

LV DISPLAY IN

(IN VOL CTRL)

VR1A

A20K

R1

5K11

R124

R7810K0

6

5K11

220uF/4V

VR2A

B10K

C18

10K0

C15

220uF/4V

22R

7

5

123

R17

C31

22P

R75

10K0

220uF/4V

C1

R127

R126

22R

1

BA15218

SW3A

3

15K0

20K0

1

22R

IC5A

BA15218

3

22E85L

(MO/ST)

IC4A

2068D

3c5e1a4d2b

X2

SCJ-0658-1-Y

3c5e1a4d2b

X1

SCJ-0658-1-Y

IC3A

3

47P C3

SW1A

22E85L

C20

VR3A

A100K

R76

10K0

(BALANCE)

R45

15K0

2068D

VR1B

R2

22RR4

R7910K0

6

5K11

R223

5K11

(R/MUTE)

220uF/4V

VR2B

C16

220uF/4V

(VOL CTRL)

A20K

5K11

7

5

R31

10K0

123

R18

20K0

C32

22P

R77

10K0

B10K

( AUX IN )

( DIRECT IN )

R16

C2

1

IC6A

3

2

IC6B

BA15218

LV DISPLAY CH1

R32

10K0

7

5

6

R46

15K0

20K0

7

47P

6

BA15218

SW2A

IC4B

5

22E85L

2068D

JR1

+15V

IC3B

C6

47P

(L/MUTE)

(VOLUME CTRL)

VR5B

A100K

R80

10K0

R48

15K0

0R

GND2

2068D

R5

R224

C21

220uF/4V

R89

470R 1/4W

R47

2M00

5K11

VR4A

R128

6

B10K

R90

22R

R8410K0

7

C33

R81

1M00

IC8B

5

123

R19

22P

2

10K0

HR

TR4

R125

2

IC5B

20K0

1

2

R44

R15

47P

2

R129

22R

2

BA15218

20K0

1

R49

15K0

1

SW6A

3

R131

22RR6

R130

22R

1

IC8A

BA15218

R8810K0

47P

3

C5

7

6

5K11

22E85L

(MO/ST)

R225

5K11

123

SW4A

22E85L

(R/MUTE)

C22

220uF/4V

IC7A

2068D

VR5A

A100K

R82

10K0

VR4B

B10K

(BALANCE)

R50

15K0

3c5e1a4d2b

X4

SCJ-0658-1-Y

LD1GRLD2GRLD3GRLD4GRLD5GRLD6

14

IC1C

LM339

8

9

11

R92

R91

110R

-15V +15V

PIN1: MAIN IN L

PIN2: MAIN IN R

123456789

IC9B

5

R33

10K0

R20

20K0

C34

R83

( AUX IN )

(-24)

13

10

100R

2

BA15218

R34

22P

6

10K0

R51

IC1D

10K0

7

15K0

LM339

R93

IC9A

BA15218

3

LV DISPLAY CH2

SW5A

22E85L

(L/MUTE)

IC7B

2068D

VR7B

5

R100

R52

GND2

(-18)

1

IC1B

LM339

6

7

R94

200R

10

C8

47P

(VOLUME CTRL)

A100K

10K0

15K0

(-12)

2

5

402R

CN1

10P-2.0

R7

R226

C23

4

6

5K11

220uF/4V

VR6A

B10K

IC1A

LM339

R95

R132

22R

R104 10K0

7

C35

R101

9

806R

R133

2

IC11B

BA15218

5

123

R21

20K0

1

22P

2

10K0

R53

15K0

(-6)

14

IC2C

8

OUT1/L

OUT1/R

22R

1

SW9A

3

X6

LM339

R96

OUT2/R

R134

22R

IC11A

3

22E85L

(MO/ST)

SW7A

IC10A

2068D

VR7A

R102

R54

3c5e1a4d2b

SCJ-0658-1-Y

(0)

13

IC2D

10

11

1K58

OUT2/L

R135

22RR8

BA15218

47P C7

5K11

R227

5K11

22E85L

(R/MUTE)

C24

220uF/4V

A100K

10K0

(BALANCE)

15K0

GR

LM339

7

R97

3K24

R105 10K0

6

VR6B

(+6)

1

7

IC12B

5

R35

10K0

123

R22

20K0

C36

22P

R103

10K0

B10K

( AUX IN )

LD7

YEL

IC2B

LM339

6

R98

1

3

2

BA15218

LV DISPLAY CH3

R36

10K0

7

5

6

R55

15K0

GND2

(+12)

2

IC2A

5

4

6K34

SW8A

IC10B

LD8

LM339

IC12A

BA15218

22E85L

(L/MUTE)

2068D

MAIN IN R

RED

(+18)

OUTPUT1

8K06

R99

+15V

MAIN IN L

-15V+15V

HPA6-CH1..6 DISPLAY

HPA6FP-DSP.SCH

C65

47/25V

R141

22R

C63

47/25V

R139

22R

C61

47/25V

R138

22R

+15V

C50

100nF

1uF

C43

84

IC12C

BA15218

84

IC11C

BA15218

84

IC9C

BA15218

84

IC8C

BA15218

84

IC6C

BA15218

84

IC5C

BA15218

84

IC10C

2068D

84

IC7C

2068D

84

IC4C

2068D

84

IC3C

2068D

C53

C54

100nF

312

IC1E

LM339

312

IC2E

LM339

84

IC23C

2068D

1K00

R87

D2A

DA204K

-15V

D2B

DA204K

6

R85

10K0

LV DISPLAY IN

HPA6

29-Mar-2002

HPA6FP.Sch

ALTO Mobile : HPA6 FRONT PANEL ( CONTROL )

A3

Titel

Size

File:

Date:

C66

47/25V

R142

22R

-15V

C64

47/25V

R140

22R

-15V

C62

47/25V

R137

22R

-15V

R136

100nF

22R

C52

100nF

+15V

C51

100nF

+15V

V-LM339

7

IC23B

2068D

R86 10K0

5

D1

BAS16

1 2 3 4 5 6 7 8

D

C

B

A

D

87654321

C

B

A

32 of

VER020314

C.C.LIN

RevisionModel No:

Drawn By:

Sheet

TIP : L-CHANNEL

RING:R-CHANNEL

R143

C10

47P

6

R9

5K11

R228

5K11

C25

220uF/4V

(VOLUME CTRL)

VR9B

A100K

22R

R110 10K0

7

5

123

C37

OUT4/R

IC14B

BA15218

R23

22P

2

R144

2

20K0

1

3c5e1a4d2b

22R

1

SW12A

3

22E85L

(MO/ST)

IC13A

R145

2068D

OUT 4

22R

IC14A

SW10A

VR9A

R146

BA15218

47P

C9

22E85L

C26

220uF/4V

A100K

X9

SCJ-0658-1-Y

22RR10

R111 10K0

6

5K11

R229

5K11

(R/MUTE)

GND2

7

IC15B

BA15218

5

R37

10K0

123

R24

20K0

C38

22P

OUT4/L

1

3

2

LV DISPLAY CH4

R38

10K0

SW11A

7

IC13B

5

6

IC15A

22E85L

2068D

BA15218

C12

(L/MUTE)

VR11B

R147

47P

R116 10K0

7

6

R11

5K11

R230

5K11

C27

220uF/4V

(VOLUME CTRL)

A100K

OUT5/R

22R

IC17B

5

123

R25

C39

22P

2

R148

22R

2

BA15218

20K0

1

3c5e1a4d2b

1

3

SW15A

IC16A

3

R149

22R

22E85L

(MO/ST)

2068D

OUT 5

IC17A

BA15218

C1147P

SW13A

C28

VR11A

R150

22RR12

R231

22E85L

(R/MUTE)

220uF/4V

A100K

X11

SCJ-0658-1-Y

R117 10K0

7

6

5K11

R39

5K11

123

R26

GND2

IC18B

5

10K0

20K0

C40

2

BA15218

22P

6

R40

OUT5/L

1

10K0

7

IC18A

BA15218

3

LV DISPLAY CH5

SW14A

22E85L

(L/MUTE)

IC16B

2068D

5

C14

47P

6

R13

5K11

R232

5K11

C29

220uF/4V

(VOLUME CTRL)

VR13B

A100K

R151

R122 10K0

7

OUT6/R

22R

IC20B

BA15218

5

123

R27

C41

22P

2

R152

2

20K0

1

3c5e1a4d2b

22R

1

SW18A

22E85L

3

R153

3

(MO/ST)

IC19A

2068D

OUT 6

22R

IC20A

SW16A

R154

BA15218

47P

C13

22E85L

C30

220uF/4V

VR13A

A100K

X13

22RR14

6

5K11

R233

5K11

(R/MUTE)

SCJ-0658-1-Y

GND2

R123 10K0

2

7

IC21B

BA15218

5

R41

10K0

123

R28

20K0

C42

22P

6

OUT6/L

1

IC21A

3

LV DISPLAY CH6

R42

10K0

SW17A

7

IC19B

2068D

5

BA15218

22E85L

(L/MUTE)

+15V

C71

R159

C69

R157

C67

R156

47/25V

22R

47/25V

22R

47/25V

22R

84

IC21C

BA15218

84

IC20C

BA15218

84

IC18C

BA15218

84

IC17C

BA15218

84

IC15C

BA15218

84

IC14C

BA15218

84

IC19C

2068D

84

IC16C

2068D

84

IC13C

2068D

HPA6

14-Mar-2002

HPA6FP-2.Sch

ALTO Mobile : HPA6 FRONT PANEL ( CONTROL )

A3

Titel

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Date:

C72

47/25V

R160

22R

-15V

C70

47/25V

R158

22R

-15V

C68

47/25V

R155

22R

-15V

R106

R56

10K0

15K0

MAIN IN R

VR8A

B10K

R107

10K0

MAIN IN L

R57

15K0

X8

R108

(BALANCE)

R58

3c5e1a4d2b

SCJ-0658-1-Y

D

10K0

15K0

VR8B

B10K

R109

10K0

( AUX IN )

R112

R59

15K0

R60

GND2

10K0

15K0

VR10A

B10K

R113

10K0

R61

15K0

X10

C

R114

10K0

(BALANCE)

R62

15K0

3c5e1a4d2b

SCJ-0658-1-Y

VR10B

B10K

R115

10K0

( AUX IN )

R118

R119

10K0

VR12A

B10K

R63

15K0

GND2

R64

15K0

R65

15K0

X12

B

R120

10K0

(BALANCE)

R66

15K0

3c5e1a4d2b

SCJ-0658-1-Y

VR12B

B10K

R121

10K0

( AUX IN )

R67

15K0

GND2

OUT3/R

123456789

CN2

12P-2.0

OUT3/L

OUT4/R

OUT4/L

OUT5/R

A

OUT5/L

101112

OUT6/R

OUT6/L

1 2 3 4 5 6 7 8

D

C

B

A

YEL

(R-MUTE)

LD27

87654321

456

SW7B 22E85L

R187

HR

TR3

470R 1/4W

+15V

R163

402R

YEL

LD20

456

14

9

(R-MUTE)

R70

2M00

R181

1M00

SW4B 22E85L

(-24)

14

IC28C

8

9

+15V

R186

470R 1/4W

R69

2M00

R180

1M00

HR

TR2

YEL

LD28

456

P

SW8B 22E85L

LD23GRLD24GRLD25GRLD26

(-24)

( 0 )

13

IC29D

IC29C

LM339

8

10

11

R175

R169

8K06

11K0

YEL

LD21

456

P

SW5B 22E85L

LD16GRLD17GRLD18GRLD19

( 0 )

13

IC28D

LM339

5

10

11

(L-MUTE)

P

LM339

5

(L-MUTE)

P

2

4

2

(+12)

IC28A

456

SW9B 22E85L

(+12)

IC29A

4

R193

39K2

456

SW6B 22E85L

LM339

7

LD29

LM339

LD22

1

GR

1

7

GR

(CLIP)

IC28B

6

(MONO)

P

(CLIP)

IC29B

6

R199

200K

(MONO)

P

RED

LM339

RED

LM339

-15V

R190

-15V

470R 1/4W

+15V

HEADPHONE-3 DISPLAY

R73

-15V

R189

470R 1/4W

+15V

HEADPHONE-2 DISPLAY

R72

2M00

R184

R183

1M00

YEL

(R-MUTE)

LD48

456

SW16B22E85L

HR

TR7

14

9

R166

402R

YEL

(R-MUTE)

LD41

456

SW13B22E85L

HR

TR6

14

9

YEL

LD49

(L-MUTE)

456

P

SW17B 22E85L

LD44GRLD45GRLD46GRLD47

(-24)

( 0 )

13

IC32D

IC32C

LM339

8

10

11

R178

R172

8K06

11K0

YEL

LD42

(L-MUTE)

456

P

SW14B 22E85L

LD37GRLD38GRLD39GRLD40

(-24)

( 0 )

13

IC31D

IC31C

LM339

8

10

11

GR

LD50

(MONO)

456

P

2

5

P

2

5

SW18B22E85L

(+12)

IC32A

4

R196

39K2

456

SW15B22E85L

(+12)

IC31A

4

LM339

LD43

LM339

7

(CLIP)

1

GR

(CLIP)

1

P

IC32B

6

R202

200K

(MONO)

P

IC31B

6

RED

-15V

LM339

-15V

RED

-15V

LM339

HEADPHONE-6 DISPLAY

HEADPHONE-5 DISPLAY

CN3

PWR LED

+15V

CON2

R221

2 1

33 of

VER020329

C.C.LIN

RevisionModel No:

Drawn By:

Sheet

HPA6

29-Mar-2002

HPA6FP-DSP.Sch

ALTO Mobile : HPA6 FRONT PANEL ( DISPLAY )

A3

Titel

Size

File:

Date:

1K2

+15V

R185

470R 1/4W

R68

2M00

R179

D9A

D9B

DA204K

R203

10K0

LV DISPLAY CH1

1M00

R215

DA204K

6

1K00

1

R201

200K

(MONO)

P

IC30B

6

R200

200K

R220

D14B

DA204K

2

1K00

LM339

1

RED

HADS6

3

-15V

C49

DA204K

IC26A

D8

1uF

2068D

-15V

HEADPHONE-4 DISPLAY

-15V

312

+15V

84

R21410K0

84

BAS16

IC32E

IC31E

IC30E

IC29E

IC28E

IC27E

IC26C

IC25C

IC24C

LM339

2068D

C60

C59

C58

C57

C56

C55

V-LM339

100nF

+15V +15V +15V +15V +15V

100nF

+15V

1 2 3 4 5 6 7 8

R162

402R

HADS2 HADS3

YEL

LD13

456

SW1B 22E85L

C44

IC24B

1uF

2068D

R161

9

-15V

(-24)

14

8

402R

HR

TR1

7

R20510K0

5

D3

BAS16

R174

R168

8K06

(R-MUTE)

456

P

SW2B 22E85L

LD9GRLD10GRLD11GRLD12

( 0 )

13

IC27D

IC27C

LM339

10

11

R167

8K06

R216

1K00

D10A

DA204K

D10B

DA204K

2

R204

10K0

LV DISPLAY CH2

LD14

HADS2

1

LM339

R173

3

11K0

YEL

5

11K0

IC24A

D4

(L-MUTE)

P

2

4

1uF

C45

2068D

BAS16

(+12)

IC27A

R192

39K2

456

SW3B 22E85L

LM339

7

R191

39K2

-15V

R20810K0

LD15

1

6

D11A

R206

GR

(CLIP)

10K0

R198

200K

(MONO)

P

RED

IC27B

LM339

R197

200K

R217

1K00

D11B

7

DA204K

6

LV DISPLAY CH3

+15V

-15V

+15V

HEADPHONE-1 DISPLAY

+15V

HADS3

1uF

C46

-15V

DA204K

IC25B

2068D

R20910K0

5

D5

BAS16

R188

470R 1/4W

R71

2M00

D12A

DA204K

R207

10K0

LV DISPLAY CH4

R218

R182

D12B

2

1K00

1M00

1

TR5

3

HR

C47

DA204K

IC25A

HADS5 HADS6

1uF

2068D

D6

456

SW10B22E85L

-15V

BAS16

R165

R171

402R

8K06

YEL

(R-MUTE)

LD34

456

P

SW11B 22E85L

LD30GRLD31GRLD32GRLD33

(-24)

14

13

IC30C

LM339

8

9

11

R164

R170

402R

8K06

HADS5

R219

1K00

D13B

7

D13A

DA204K

R21210K0

5

6

R210

10K0

LV DISPLAY CH5

LD35

R177

11K0

YEL

( 0 )

IC30D

10

R176

11K0

C48

DA204K

IC26B

D7

(L-MUTE)

P

LM339

1uF

2068D

R195

39K2

LD36

GR

456

SW12B22E85L

(+12)

(CLIP)

2

IC30A

LM339

5

7

4

R194

39K2

-15V

D14A

R21310K0

R211

10K0

BAS16

LV DISPLAY CH6

D

C

B

A

D

PHONE 1

PHONE 2

C

PHONE 3

PHONE 4

B

PHONE 15

A

00 of

PHONE 6

RevisionModel No:

X10

4321

JY6351G-02

3c5e1a

4d

2b

X9

JY6351G-02

3c5e1a

4d

2b

X12

JY6351G-02

X11

JY6351G-02

3c5e1a

4d

2b

3c5e1a

4d

2b

X14

JY6351G-02

X13

JY6351G-02

3c5e1a

4d

2b

3c5e1a

4d

2b

123456789

X16

JY6351G-02

X15

JY6351G-02

3c5e1a

4d

2b

3c5e1a

4d

2b

10

CN2

10P-2.0

X18

JY6351G-02

3c5e1a

X17

JY6351G-02

3c5e1a

X20

JY6351G-02

Drawn By:

X19

JY6351G-02

3c5e1a

4d

2b

3c5e1a

4d

2b

4d

2b

4d

2b

ALTO Mobile : HPA6 REAR BOARD

Titel

HPA6 VER020225

A3

Size

Sheet

14-Mar-2002

HPA6RP.Sch

File:

Date:

JP1

123456789

-15V+15V

CN3

12P-2.0

+15V

TT4

101112

TT3

TT5

-15V

C9

+21V

CN1

4

C7

3P-3.9

213

100nF

10/50V

7

R6

20K0

C11

20P

IC1B

2068D

R7

5

6

20K0

C13

20P

1

R8

20K0

IC1A

2068D

IC3

R9

20K0

3

2

7815

C5

C12

20P

R2

10K0

R1

10K0

213

R3

C17

10K0

R10

10K0

3c5e1a4d2b

C18

47P

R4

10K0

C19

47P

R11

10K0

213

R5

R12

10K0

3c5e1a4d2b

10K0

C14

20P

C20

47P

+15V

C15

100nF

84

IC1C

2068D

213

4

3c5e1a4d2b

1000/35V

C2

100nF

C16

100nF

C1

100nF

-15V

C10

100nF

C8

10/50V

IC4

7915

C6

1000/35V

BD1

RB154

123

3c5e1a4d2b

-21V

C4

100nF

C3

100nF

X1

JY-5042-030G

X2

JY6351G-02

MAIN IN L

D

X3

JY-5042-030G

X4

JY6351G-02

MAIN IN R

C

X5

JY-5030-030G

X6

JY6351G-02

MAIN OUT L

B

X7

JY-5030-030G

X8

JY6351G-02

MAIN OUT R

1 2 3 4

A

HPA6FP Top Scilkscreen

4.Printed Circuit Diagram

HPA6FP Top Solder Mask

HPA6FP Top Layer

HPA6FP Bottom Scilkscreen

Alto HPA6 Schematic

Specifications and Main Features

Frequently Asked Questions

User Manual