Alto EQU SERIES-SM Schematic

Service Manual

Model: EQU SERIES

15/31 Band Graphic Equalizer

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

Type

E

QU131

EQU215
EQU2215
EQU131VU
EQU231VU / 231LED
EQU231TWIN

1 31 Band: 1/3 octave , ISO spacing (1H series)
2 15 Band: 2/3 octave , ISO spacing (1H series)
2 15 Band: 2/3 octave , ISO spacing (2H series)
1 31 Band: 1/3 octave , ISO spacing (2H series)
2 31 Band: 1/3 octave , ISO spacing (2H series)
2 31 Band: 1/3 octave , ISO spacing (4H series)

Slider travel

Range

Input connections

Input impedance

Maximum input level

Output connections

Output impedance

Maximum output level

Load impedance

High pass filter

Low pass filter

Frequency response

THD+N%

S/Nratio

Power supply

Consumption

EQU131/131VU
EQU215/2215
EQU231VU / 231LED/231TWIN

20mm with positive centre detente
(EQU131/EQU215/EQU231VU/EQU231LED)
60mm with positive centre detente
(EQU131VU/EQU2215/EQU231TWIN)

6dB or 12dB selectable

Active balanced XLR and 1/4" TRS
Unbalanced RCA

20k (bal.)
15k (unbal.)

18dBv

Active balanced XLR and 1/4" TRS
Unbalanced RCA

600

16dBv

>10K

40Hz (12dB/oct) fixed-button type .

16KHz (12dB/oct) fixed-button type

20Hz to 50KHz at - 3dB

0.02% (@ 1KHz , all VR at middle position)

93dB (@ 1KHz )

110V-120VAC -60Hz
220V-240VAC -50Hz

1 31 band, 1/3 octave, ISO spacing: 7W
2 15 band, 2/3 octave, ISO spacing: 9W
2 31 band, 1/3 octave, ISO spacing: 12.5W

Dimensions

483(W) 220(D) 44(H)(19" 8.66" 1.7")mm (1H series)

483(W) 220(D) 88(H)(19" 8.66" 3.5") mm (2H series)

483(W) 220(D) 177.8(H)(19" 8.66" 7") mm (4H series)

z 1 Block Diagram

1 Block Diagram

1 Block Diagram1 Block Diagram

 EQU-131(31 Sets Band)

EQU-131(31 Sets Band)

EQU-131(31 Sets Band)EQU-131(31 Sets Band)

LOW-PASS FILTER

HI-PA S S FI LTER

SIGNAL AMP .

INPUT AMP.

U13-A

U2-A

U1-B

LEVEL

U1-A

LEVEL SENS OR

BUFFER

U3-A U11-B

RANGE

CLIP

U4-A

U5~U22

31 Sets BAND PASS FILTER

U3-B

RANGE

U2-B

SIGNAL INVERSE

+15V

128

NONCNO

6

3

TSTRSRSS

7

NC

IN

K1

BYPASS

5

4

1

3

S

2

R

IN

W

OUT

INPUT

FEM A L E

IN

1.

1.1111

1.1.

1

3

2

TSTRSRSS

OUT

S

OUT

 EQ

EQUUUU-215

EQEQ

-215

-215-215

LOW-P AS S FI LTER

HI-P AS S F I LTER

SI GNAL AMP.

INPUT AMP.

U13-B

BUFFER

U13-A

U1-B

LEVEL

U1-A

U2-B U2-A

RANGE

CLIP

U12-A

LEVEL SENSOR

U5~U22

15 Sets BAND P ASS FI LTER

U4-A

RANGE

U4-B

SIGNAL I NVER S E

+15V

128

NONCNO

6

3

TSTRSRSS

7

NC

IN

K1

BYPASS

5

4

1

3

S

2

R

1.

1.2222

1.1.

IN

W

OUT

INPUT

FEM A LE

IN

1

3

2

TSTRSRSS

OUT

S

OUT

 EQ

EQUUUU----231

EQEQ

LOW-PASS FILTER

231VU

VU,EQU-131VU

231231

U13-B

,EQU-131VU

VUVU

,EQU-131VU,EQU-131VU

U5~U22

BUFFER

31 Sets BAND PASS FILTER

U13-A

HI-PASS FILTER

U1-B

SIGNAL AM P.

LEVEL

U1-A

INPUT AMP.

LEVEL SENSOR

U3-A U11-B

RANGE

CLIP

U3-B

U4-A

U2-B

RANGE

SI GNAL I NVER SE

+15V

128

7

NONCNO

NC

6

3

TSTRSRSS

IN

VU METER

K1

BYPASS

5

4

1

3

S

2

R

IN

W

OUT

1.

1.3333

1.1.

INPUT

FEMALE

IN

1

3

2

TSTRSRSS

OUT

S

OUT

 EQ

V

EQUUUU-231LED

EQEQ

-231LED

-231LED-231LED

LOW-P AS S F I LTER

U13-B

U13-A

HI-PASS FILTER

U1-B

SI GNAL AMP.

LEVEL

U1-A

INPUT AMP.

LEVEL SENSOR

BUFFER

U3-A U11-B

RANGE

CLIP

U4-A

U5~U22

31 Sets B AND P AS S F I LTER

U3-B

RANGE

U2-B

SIGNAL INVERS E

LED

128

7

NONCNO

NC

K1

BYPASS

5

4

6

3

15

1

3

TSTRSRSS

IN

S

2

R

IN

W

OUT

1.

1.4444

1.1.

INPUT

FEM ALE

IN

1

3

2

TSTRSRSS

OUT

S

OUT

z 2 Schematic

2 Schematic

2 Schematic2 Schematic

 P-1215M(Page 1 of 2)

P-1215M(Page 1 of 2)

P-1215M(Page 1 of 2)P-1215M(Page 1 of 2)

2.

2.1111

2.2.

 P-1215M(Page 2 of 2)

P-1215M(Page 2 of 2)

P-1215M(Page 2 of 2)P-1215M(Page 2 of 2)

2.

2.2222

2.2.

 P-1131M(Page 1 of 2)

P-1131M(Page 1 of 2)

P-1131M(Page 1 of 2)P-1131M(Page 1 of 2)

2.

2.3333

2.2.

 P-1131M(Page 2 of 2)

P-1131M(Page 2 of 2)

P-1131M(Page 2 of 2)P-1131M(Page 2 of 2)

2.

2.4444

2.2.

 P-1215SW

P-1215SW

P-1215SWP-1215SW

2.

2.5555

2.2.

 P-1215VR

P-1215VR

P-1215VRP-1215VR

2.

2.6666

2.2.

 P-1131VR

P-1131VR，，，，P-2131VR

P-1131VRP-1131VR

P-2131VR

P-2131VRP-2131VR

2.

2.7777

2.2.

 P-1215PWR

P-1215PWR

P-1215PWR P-1215PWR

2.

2.8888

2.2.

 P-1215HFS

P-1215HFS

P-1215HFSP-1215HFS

2.

2.9999

2.2.

 P-1215HL

P-1215HL

P-1215HLP-1215HL

2.

2.10

10

2.2.

1010

 P-2215VR

P-2215VR

P-2215VRP-2215VR

2.

2.11

11

2.2.

1111

 P-2215VU

P-2215VU

P-2215VUP-2215VU

2.

2.12

12

2.2.

1212