Alto X-P234 Schematic

Service Manual

Model: X-P234 (2,3-WAY STEREO 4-WAY MONO )

ACTIVE CROSSOVER

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

INPUT
Connectors	XLR
Type	Electronically servo-balanced, RF filtered
Impedance	Balanced >50K Ohms, unbalanced >25K Ohms
Max. Input Level	+22dBu typical, balanced or unbalanced
CMRR	>40dB, typically > 55 dB at 1 KHz
OUTPUT
Connectors	XLR
Type	Electronically servo-balanced, RF filtered
Impedance	Balanced 60 Ohms, unbalanced 30 Ohms
Max. Output Level	+20dBu balanced or unbalanced
PERFORMANCE
Bandwidth	20Hz to 20KHz, +0/-0.5dB
Frequency Response	<5Hz to>90KHz, +0/-3dB
Signal to Noise	Ref: +4dBu, 20Hz to20KHz,unweighted
	Stereo Mode:	Mono Mode:
Low Output	>93dBu	>93dBu
Low-Mid Output		>94dBu
Mid Output	>95dBu
High-Mid Output		>94dBu
High Output	>90dBu	>88dBu
Dynamic Range	>106dB,unweighted
THD& Noise	Limiter Off	Limiter On
	<0.04%	<0.5 %
Interchannel Crosstalk	High to Low:	<93dBu
	High to Mid:	<94dBu
	Mid to Low:	<95dBu
	High to High-Mid:	<95dBu
	High-Mid to Low-Mid:	<95dBu
	Low-Mid to Low:	<92dBu
CROSSOVER
Filter Type	Linkwitz-Riley, 24dB/Octave, state-variable
Stereo Mode Frequencies	1	10
Low/High	44Hz to 930Hz	440Hz to 9.3KHz
Low/Mid	44Hz to 930Hz	440Hz to 9.3KHz
Mid /High	440Hz to 9.3KHz
Mono Mode Frequencies	1	10
Low/Low-Mid	44Hz to 930Hz	440Hz to 9.3KHz
Low-Mid/High-Mid	440Hz to 9.3KHz
High-Mid/High	440Hz to 9.3KHz
FUNCTION SWITCHES
Front Panel
Low Cut	Activates 25 Hz Butterworth, 12 dB/Octave high-pass filter
Mute	Mutes the individual output
Phase Invert	Inverts the phase at the individual output
CD Horn	Corrects CD horn frequency response above 3.5KHz
Limiter	Activates the limiter function for all outputs
Rear Panel
Xover Frequency	Mutiplies crossover frequency range by 10
Mode	Selects stereo /mono and 2/3/4-way operation
LF Sum	Selects normal stereo or mono-summed low frequency operation
	ON=Channel1+6dB Louder,Channal2: the same as before

CONTROLS
Input	Controls the input gain(+/-12dB)
Xover Frequency	Controls the crossover frequency
Delay	Controls the delay at the low output(0 to 2 msec.)
Gain	Controls the output gain(+/-6dB)
Threshold	Controls the threshold of the limiter (-6dB to OFF)
POWER SUPPLY
Connector type	3-pole IEC, grounded
Type	serve controlled, stabilized
Mains supply	95-120V /210-240V ,60-50Hz
Power Rating	<17W
Fuse	210-240V: T250mAL 250VAC
	95-120V: 500mA 250VAC
PHYSICAL
Dimensions	483(W) 194.5(D) 44(H)mm(19" 7.7" 1.7")
Net Weight	3.3Kg(7.27lb)

	1	2	3	4	5	6	7	8

						ON / OFF	A-CHANNEL
			LOW GAIN			MUTE	LOW OUTPUT
				PHASE	DELAY		2
						LIMITER	3
D							1
INPUT							A-CHANNEL
A -CHANNEL SIGNAL
		FREQ. x1 OR x10				MUTE	MID OUTPUT
LOW CUT	GAIN		MID GAIN	PHASE			2
2						LIMITER	3
3							1
1
		XOVER
							A-CHANNEL
			HIGH GAIN			MUTE	HIGH OUTPUT
				PHASE	CD HORN		2
						LIMITER	3
							1

MODE

	ON	-----	2-WAY STEREO	-----	OFF
C	OFF	-----	3-WAY STEREO	-----	OFF
	OFF	-----	4-WAY MONO	-----	ON
	ON	-----	NOT VALID	-----	ON					B-CHANNEL
						LOW GAIN			MUTE	LOW OUTPUT
							PHASE	DELAY		2
									LIMITER	3
										1
INPUT										B-CHANNEL
B -CHANNEL SIGNAL
			FREQ. x1 OR x10						MUTE	MID OUTPUT
LOW CUT	GAIN					MID GAIN	PHASE			2
2									LIMITER	3
3										1
1
					XOVER
										B-CHANNEL
						HIGH GAIN			MUTE	HIGH OUTPUT
B							PHASE	CD HORN		2
										3
									LIMITER
										1

	STEREO MODES FREQUENCIES	x1	x10
	(2-WAY) LOW / HIGH	44 Hz TO 930 Hz	440 Hz TO 9.3 KHz
	(3-WAY) LOW / MID	44 Hz TO 930 Hz	440 Hz TO 9.3 KHz
	MID / HIGH	440 Hz TO 9.3 KHz
	MONO MODES FREQUENCIES	x1	x10
	(4-WAY) LOW / LOW-MID	44 Hz TO 930 Hz	440 Hz TO 9.3 KHz
	LOW-MID / MID-HIGH	440 Hz TO 9.3 KHz
A	MID-HIGH / HIGH	440 Hz TO 9.3 KHz

						Titel	SCX-P234 BLOCK DIGRAM
						Size	Model No:			Revision
						A4	SCX-P234			V1.0
						Date:	2-Nov-2002		Sheet 1	of 1
						File:	P234 BLOCK DIGRAM.Sch		Drawn By:	TASY J.S.
1	2	3	4	5	6		7			8

D

C

B

A

1

2

3

4

5

6

7

8

TO CN2-16

C56

C85

CN2

4N7

CD HORN2

C20

SW7

24PIN

IC9A

20P

R107

3

47uF

MUTE

24

CD HORN1

2068

R46

47K5

1

23

C23

2

30K1

R98

22

HI

47UF/25V

R50

R109

R96

21

R108

C84

2K67

10K

R106

20

TO CN2-22

15K

IC10B

10K

D

9

180R

15N

SW8

47K5

19

R101

C81

8

6

TL074

CD HORN

C21

18

68R

VR5

10

7

R49

220uF

100P

17

C18

10KB

IC5C

R52

5

2K21

16

R51

C24

C55

47uF

D6

+15V

15

TL074

2K21

100P

4K99

47uF

BAS16

14

-15V

13

R45

R103

LED11

12

2K21

560K

5

RD

11

-15V

+15V

7

SW6

10

6

R17

INV

9

IC5D

IC9B

R105

R24

R48

R47

13

1K5

8

TL07414

R104

10K

3K22

10K

2K21

R182

SW16

2068

7

12

6K34

Q10

6

18K2

LIMITER

BR

R102

5

4

Q9

560K

D5

3

2N7002

BAS16

2

R181

R100

R99

C22

1

IC10A

10M

5K11

2K21

2

VR11

TL074

1 LIMITER

C19

R97

4.7uF

10KB

3

100K

4.7uF

TO CN2-20

IC10D

R39

C51

R60

R59

C

R123

15K

20P

10K

37K4

C8

SW3

LO

TL074

C5

IC7A

10K

MUTE

TO CN2-10

12

47uF

3

2068

47uF

R43

14

C6

1

13

30K1

IC6B

R64

2

47uF

C58

10K

TO CN1-2

R55

6

2068

R62

IC5A

R85

R120

511R

5N6

7

10K

2

TL074

5

47K5

10K

VR3

R37

R74

C61

1

C10

R118

10KB

4K99

3

68R

220uF

100P

R119

10K

SW2

VR2A

D2

+15V

INV

10K

R71

100KB

BAS16

R41

3K32

-15V

10K

R76

IC7B

LED7

560K

5

RD

2068 7

VR2B

6

LOW CUT

R84

R4

100KB

R58

R80

1K5

TO CN2-23

C57

2

R75

10K

R57

27K4

6K34

Q6

C48

5N6

1

560K

511R

BR

150N

3

CN1

TO CN1-19

R34

IC6A

R65

D1

5K11

20PIN

30K1

2068

R56

Q5

BAS16

C3

20

R27

C1

10K

2N7002

R21

C12

19

47uF

15K

R29

47uF

IC4B

10M

4.7uF

18

47P

6

2068

C7

R63

17

R28

SW1

7

B

22uF

100K

16

20K

LOW CUT

5

15

2

VR1

14

1

C49

13

50KB

3

150N

12

IC4A

11

2068

10

R30

C2

SW5

R33

IC8A

9

R26

20K

47uF

3

MUTE

60K4

8

15k

2068

7

2

1

6

R86

C15

5

10K

47uF

4

TO CN2-18

C16

R95

R91

3

C80

47K5

C52

220uF

2

68R

20P

100P

1

R44

D4

+15V

C4

30K1

C13

R89

BAS16

MID

R40

47uF

-15V

10K

47UF/25V

IC8B

LED9

TO CN1-1

15K

IC5B

R90

560K

5

2068

RD

6

TL074

5

7

6

7

VR4

R94

R6

10KB

R38

R93

R92

1K5

10K

4K99

6K34

560K

Q8

R88

BR

A

D3

Q9

5K11

SW4

2N7002

BAS16

R22

C17

INV

R42

10M

Titel

R23

R87

4.7uF

C14

10K

P234FP-1(CH1)

3K22

100K

10uF

Size

Model No:

Revision

A3

X-P234

V1.0

Date:

7-Jun-2002

Sheet 1

of 3

File:

P234FP-1.SCH

Drawn By:

TASY J.S.

D

C

B

A

	1	2	3	4	5	6	7	8

1

2

3

4

5

6

7

8

TO CN2-4

C97

C86

CN2

4N7

C44

SW15

24PIN

IC16A

20P

R110

3

47uF

MUTE

24

2068

R133

47K5

23

C29

IC?C

2

1

30K1

R173

22

47UF/25V

R114

R170

HI

R137

TL074

CD HORN1

21

R117

C88

2K67

10K

R180

20

TO CN2-12

15K

10K

D

9

180R

15N

47K5

19

CD HORN2

R175

C104

8

10

C45

18

68R

VR10

10

8

R136

220uF

100P

17

R138

C42

10KB

IC12C

9

2K21

16

R139

C96

47uF

D12

2K21

C25

+15V

15

TL074

100P

4K99

47uF

BAS16

14

-15V

13

R132

R177

LED22

12

2K21

560K

5

RD

11

7

SW14

10

6

R20

INV

9

IC12D

IC16B

R179

R154

R135

R134

13

1K5

8

TL07414

R178

2068

10K

3K22

10K

2K21

Q16

7

12

6K34

6

BR

R176

5

4

Q15

560K

D11

3

2N7002

BAS16

2

R174

R172

C46

1

10M

5K11

C43

R171

4.7uF

LIMITER

100K

4.7uF

TO CN2-8

R126

C92

R145

R144

C

LO

C31

15K

20P

10K

37K4

IC14A

C34

SW10

MUTE

TO CN2-9

47uF

3

2068

47uF

R130

C32

1

30K1

IC13B

R148

2

47uF

C99

10K

TO CN3-2

R140

6

2068

R146

IC12A

7

R157

511R

5N6

10K

2

TL074

5

47K5

VR8

R124

R152

C100

1

C35

10KB

4K99

3

68R

220uF

100P

SW11

VR7A

D8

+15V

INV

R25

100KB

BAS16

R128

3K32

-15V

10K

R151

IC14B

LED8

560K

5

RD

2068 7

VR7B

6

LOW CUT

R156

R18

100KB

R143

R155

1K5

TO CN2-14

C98

2

R153

10K

R142

27K4

6K34

Q12

C89

5N6

1

560K

511R

BR

150N

3

CN3

TO CN3-1

R122

IC13A

R149

D7

5K11

20PIN

30K1

2068

R141

Q11

BAS16

C28

20

R112

C26

10K

2N7002

R150

C36

19

47uF

15K

R115

47uF

IC11B

10M

4.7uF

18

47P

6

2068

C33

R147

17

R111

B

SW9

7

22uF

100K

16

20K

LOW CUT

5

15

2

VR6

14

C191

1

13

50KB

3

150N

12

IC11A

11

2068

10

R116

C27

SW13

R121

IC15A

9

R113

20K

47uF

3

MUTE

60K4

8

15k

2068

7

2

1

6

R158

C39

5

10K

47uF

4

TO CN2-6

C40

R169

R165

3

C103

47K5

C93

220uF

2

68R

20P

100P

1

R131

D10

+15V

C30

30K1

C37

R160

BAS16

MID

R127

47uF

-15V

10K

47UF/25V

IC15B

LED20

TO CN3-20

15K

IC12B

R164

560K

5

2068

RD

6

TL074

5

7

6

7

VR9

R168

R19

10KB

R125

R167

R166

1K5

10K

4K99

6K34

560K

Q14

R161

BR

A

D9

Q13

5K11

SW12

2N7002

BAS16

R163

C41

INV

R129

10M

Titel

R162

R159

4.7uF

C38

10K

P234FP-2(CH2)

3K22

100K

10uF

Size

Model No:

Revision

A3

X-P234

V1.0

Date:

7-Jun-2002

Sheet 2

of 3

File:

P234FP-2.SCH

Drawn By:

TASY J.S.

D

C

B

A

	1	2	3	4	5	6	7	8

D

C

B

A

1

				TO CN2-3
				TO CN2-5
				TO CN2-17
CN2				TO CN2-19
24PIN				TO CN2-1
24
23				TO CN2-2
22
21				TO CN2-11
20
19				TO CN2-21
18
17				TO CN2-24
16
15
14
13
12
11
10
9
8
7				TO CN2-13
6
5
4				TO CN2-15
3
2
1				TO CN2-7

+15V

C50	8
104P

IC4C

2068

-15V	C47	4
	104P
+15V
	C90	8
	104P

IC11C

2068

-15V	C87	4
	104P

2

-15V

LED13 YE

LED2

YE

-15V

+15V

	R35	R2	LED21
			GN
	15K	470R
	Q2		LED6
	HR
			GN
			LED5
			GN
	R36	LED1	LED3
	39K2
		GN	GN
	LED19	LED15	LED8
	GN	GN	GN

LED17		LED16			LED14
GN		GN			GN

	C53	4	C73	8	8
	104P		104P
		IC5E		IC6C	IC7C
		TL074		2068	2068
	C54	11	C71	4	4
	104P		104P
	C94	4	C102	8	8
	104P		104P
		IC12E		IC13C	IC14C
		TL074		2068	2068
	C95	11	C101	4	4
	104P		104P

3	4

+15V	+15V

R54	R5	R61	R3
15K	470R	15K	470R
	Q3		Q4
	HR		HR

												CN3
R53							R66					20PIN
39K2							39K2					20
												19
												18
												17
												16
												15
												14
												13
												12
												11
												10
												9
LED4												8
												7
GN
												6
												5
												4
												3
				LED12				LED10				2
												1
				GN				GN

	8	C83	8	4
		104P
	IC8C		IC9C	IC10E
	2068		2068	TL074
	4	C82	4	11
		104P
	8		8
	IC15C		IC16C
	2068		2068
	4		4

TO CN3-9								TO CN1-12
TO CN3-3				VR14A				TO CN1-18
				C50K
TO CN3-10					CN1			TO CN1-11
				VR14B
TO CN3-4					20PIN			TO CN1-17
				C50K
TO CN3-7					20			TO CN1-14
					19
				VR14C
TO CN3-5					18			TO CN1-16
				C50K	17
TO CN3-8					16			TO CN1-13
					15
				VR14D
TO CN3-6					14			TO CN1-15
				C50K	13
TO CN3-17					12			TO CN1-4
					11
				VR15A
TO CN3-11					10			TO CN1-10
				C50K	9
TO CN3-18					8			TO CN1-3
					7
				VR15B
TO CN3-12					6			TO CN1-9
				C50K	5
TO CN3-15					4			TO CN1-6
					3
				VR15C
TO CN3-13					2			TO CN1-8
				C50K	1
TO CN3-16								TO CN1-5
TO CN3-14				VR15D				TO CN1-7
				C50K

D

VR12A

C50K

VR12B

C50K

VR12C

C50K

VR12D

C50K

C

VR13A

C50K

VR13B

C50K

VR13C

C50K

VR13D

C50K

B

Titel				A
P234FP-3
Size	Model No:		Revision
A3	X-P234		V1.0
Date:	7-Jun-2002	Sheet 3	of 3
File:	P234FP-3.SCH	Drawn By:	TASY J.S.

	1	2	3	4

	1	2	3	4	5	6	7	8

						C29
						47P
		C98				R46
		47P				26K1
	X3
		R3		R43
D	CHANNEL1
		13K3		13K3			IC9A
	1				2	-
							20681
	2
	3				3	+
	4
		R34		R44		R45
		13K3		13K3
			C97			26K1
			47P
						C28
						47P
						C30
						47P
						R48
			C33			26K1
	X7		47P
		R53		R51
	CHANNEL2						IC9B
		13K3		13K3
	1				6		2068
						-
	2						7
	3				5	+
	4
							R49
		R52		R50
			C32				26K1
		13K3		13K3
C			47P
						C31
						47P
	TO CN3-6
	TO CN3-14		TO CN1-10
	TO CN1-18		TO C7

-15V

-15V -15V

-15V

SW4	SW3
MODE	MODE

B CN2

2

4

6 +15V

8 -15V

10

12

14

16

18

20

22

24

A

TO CN2-2

-17	C12
CN2TO	47UF/25V

TO CN2-11

-19
	C13
CN2TO	47UF/25V

-15V

SW2

LF SUM

TO CN2-21

C14

CN2 47UF/25V

23

21

19

17

15

13

11

9

7

5

3

1

+15V

				8		8
				IC9C			IC10C
				2068			2068
-15V
				4		4

R64

10K

R58

3K16

R54

10K

R62

2K67

R77

10K

R71

3K16

R67

10K

R75

2K67

R90

10K

R85

3K16

R80

10K

R89

2K67

C47

104P

C17 104P

C36

47P

	R65 5K76
2			IC13A
	-		2068 1
3
	+
	R61 4K53
	R60 3K24
	R59 4K53
5			IC13B
	+		2068 7
6
	-
	R55		6K04
	C39
	47P
	R78	5K76

2IC14A

-2068 1

3	+
	R74	4K53
	R73	3K24
	R72 4K53
5	+	IC14B
		2068 7
6
	-
	R68	6K04
	C43
	47P
	R91	5K76
2	-	IC15A
		2068 1
3
	+
	R87	4K53
	R86 3K24
	R83	5K76
5	+	IC15B
		20687

6	-
	R81
	6K04

8		8
IC11C			IC12C
2068			2068
4		4

CHANNEL 2

	R63
	60R4	TO X8-3
		C38
		470P
	R66
	3K16
	R56
	60R4	TO X8-2
		C37
		470P

R76

60R4	TO X9-3
	C44
	470P
R79
3K16
R69
60R4
	TO X9-2
	C41
	470P

R88
60R4	TO X10-3
	C46
	470P
R92
3K16
R82
60R4
	TO X10-2
	C45
	470P

C23	8	C34	8
104P		104P
	IC13C		IC14C
	2068		2068
C24		C35
104P	4	104P	4

4

3

2

1

X8

LO OUTPUT

4

3

2

1

X9

MID OUTPUT

4

3

2

1

X10

HIGH OUTPUT

C9

47UF/25V

TO CN2-5

C10

47UF/25V

TO CN2-7

C11

47UF/25V

TO CN2-9

R14

10K

R8

3K16

R4

10K

R12

2K67

R27

10K

R21

3K16

R17

10K

R25

2K67

R42

10K

R33

3K16

R30

10K

R38

2K67

8	C40
	104P
IC15C
2068
	C42
4	104P

C18

47P

	R15 5K76				CHANNEL 1
				R13
2			IC10A			D
	-		2068 1	60R4	TO X4-3
3
	+				C19
	R11 4K53
					470P
	R10 3K24			R16		4
						3
				3K16
						2
	R9 4K53					1
						X4
5			IC10B			LOW OUTPUT
	+		2068 7
6					TO X4-2
	-			R6
					C99
	R5		6K04	60R4
					470P
	C21
	47P
	R28	5K76
2			IC11A	R26
3	-		2068 1	60R4	TO X5-3
	+				C22	C
					470P
	R24	4K53				4
				R29
	R23	3K24				3
				3K16		2
						1
	R22 4K53					X5
						MID OUTPUT
5			IC11B	R19
	+
6			2068 7	60R4	TO X5-2
	-
					C20
					470P
	R18	6K04
	C25
	47P
	R41	5K76
2	-		IC12A	R39
3			2068 1	60R4	TO X6-3
	+				C46
					470P	B
	R37	4K53
						4
				R42
	R36 3K24					3
				3K16
						2
						1
	R35	5K76				X6
			IC12B	R32
5	+					HIGH OUTPUT
			20687	60R4
6					TO X6-2
	-
					C45
					470P
	R31
	6K04

A

Titel

P234PU-1

Size	Model No:		Revision
A3	X-P234		V1.0
Date:	7-Jun-2002	Sheet 1	of 2
File:	P234PU-1.SCH	Drawn By:	TASY J.S.

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