Service

GM-X944/X1R/UC

Manual ORDER NO.

CRT2483

BRIDGEABLE FOUR-CHANNEL POWER AMPLIFIER

GM-X944 X1R/UC,EW,ES

CONTENTS
1. SAFETY INFORMATION............................................2 6. ADJUSTMENT .........................................................24
2. EXPLODED VIEWS AND PARTS LIST ......................2 7. GENERAL INFORMATION.......................................25
3. SCHEMATIC DIAGRAM.............................................6 7.1 DISASSEMBLY ..................................................25
4. PCB CONNECTION DIAGRAM................................12 8. OPERATIONS AND SPECIFICATIONS ....................26
5. ELECTRICAL PARTS LIST........................................18

PIONEER CORPORATION 4-1, Meguro 1-Chome, Meguro-ku, Tokyo 153-8654, Japan

PIONEER ELECTRONICS SERVICE INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A.
PIONEER EUROPE N.V. Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium
PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936

C PIONEER CORPORATION 2000 K-ZZA. MAR. 2000 Printed in Japan

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1. SAFETY INFORMATION
- GM-X944/X1R/UC

CAUTION

This service manual is intended for qualified service technicians; it is not meant for the casual do-it-yourselfer.
Qualified technicians have the necessary test equipment and tools, and have been trained to properly and safely repair
complex products such as those covered by this manual.
Improperly performed repairs can adversely affect the safety and reliability of the product and may void the warranty.
If you are not qualified to perform the repair of this product properly and safely; you should not risk trying to do so
and refer the repair to a qualified service technician.

WARNING

This product contains lead in solder and certain electrical parts contain chemicals which are known to the state of
California to cause cancer, birth defects or other reproductive harm.
Health & Safety Code Section 25249.6 - Proposition 65

2. EXPLODED VIEWS AND PARTS LIST

2.1 PACKING

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NOTE:
- Parts marked by “*” are generally unavailable because they are not in our Master Spare Parts List.
- Screws adjacent to ∇ mark on the product are used for disassembly.

- PACKING SECTION PARTS LIST

Part No.
Mark No. Description GM-X944/X1R/UC GM-X944/X1R/EW GM-X944/X1R/ES
1 •••••
2 Screw BYC40P180FZK BYC40P180FZK BYC40P180FZK
3 Polyethylene Bag HEG0011 HEG0011 HEG0011
4 Polyethylene Bag HEG0021 HEG0021 HEG0021
5 Carton HHG0248 HHG0249 HHG0250

6 Contain Box HHL0248 HHL0249 HHL0250

7 Protector HHP0079 HHP0079 HHP0079
8-1 Owner’s Manual HRD0138 HRD0139 HRD0140
8-2 Owner’s Manual Not used Not used HRD0141
* 8-3 Warranty Card Not used HRY1157 Not used

* 8-4 Card ARY1048 Not used Not used

* 8-5 PRC HRY0012 Not used Not used
9 Cover HNS0101 HNS0101 HNS0101
10 Protector HHP0096 HHP0096 HHP0096

- Owner's Manual
Model Part No. Language
GM-X944/X1R/UC HRD0138 English, French
GM-X944/X1R/EW HRD0139 English, Spanish, German,
French, Italian, Dutch
GM-X944/X1R/ES HRD0140 English, Spanish
HRD0141 Portuguese(B), Arabic

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2.2 EXTERIOR

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(1) EXTERIOR SECTION PARTS LIST

Mark No. Description Part No. Mark No. Description Part No.
1 Screw BSZ30P050FZK 26 Terminal(CN901) HKE0020
2 Screw(M3x12) CBA1323 27 Connector(CN301) HKE0030
3 Screw(M3x5) HBA0006 28 Clip HNC0054
4 Screw(M3x8) HBA0011 29 Holder HNC0076
5 Screw(M2.6x6) HBA0012 30 Bar HNR0124

6 Screw(M3x16) HBA0020 31 Heat Sink HNR0148

7 Panel See Contrast table(2) 32 Heat Sink HNR0149
8 Case See Contrast table(2) 33 Network Unit See Contrast table(2)
9 Holder HNC0078 34 Connector(CN102) CKS3145
10 Heat Sink See Contrast table(2) 35 Connector(CN104) CKS3145

11 Plate HNS0077 36 Clip HNC0054

12 Plate HNS0080 37 Screw PPZ30P100SAD
13 Cover HNS0101 38 Light Pipe Unit HXA0322
14 Spacer HNV0016 39 Fan Motor HXM0001
15 Amp Unit See Contrast table(2) 40 Screw PPZ30P100FZK

16 Screw BBZ30P060FMC 41 Thermistor(TH901, 902) CCX1013

17 Screw(M3x14) CBA1382 42 Thermistor(TH904) CCX1027
18 Terminal(CN905) CKF1059 43 FET 94-4981
19 Plug(CN906) CKS1035 (Q361, 362, 363, 364, 365, 366, 367, 368)
20 Connector(CN101) CKS3146 44 FET STP50NE08
(Q905, 906, 911, 912, 913, 914)
21 Connector(CN103) CKS3146
22 Fuse HEK0030 45 Transistor(Q907) 2SD2395
23 Pin Jack(CN852) HKB0002 46 Diode(D910) FML22R
24 Pin Jack(CN851) HKB0006 47 Transistor(Q908) 2SB1566
25 Fuse Holder HKE0012 48 Diode(D907) FML22S
49 FET 94-4980
(Q353, 354, 355, 356, 357, 358, 359, 360)

50 Screw BBZ30P140FMC
51 Screw BBZ30P060FMC

(2) CONTRAST TABLE

GM-X944/X1R/UC, EW and ES are constructed the same except for the following:
Part No.
Mark No. Description GM-X944/X1R/UC GM-X944/X1R/EW GM-X944/X1R/ES
7 Panel HNB0121 HNB0104 HNB0121
8 Case HNB0122 HNB0106 HNB0122
10 Heat Sink HNR0160 HNR0165 HNR0160
15 Amp Unit HWH0134 HWH0123 HWH0135
33 Network Unit HWG0020 HWG0016 HWG0021

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3. SCHEMATIC DIAGRAM
3.1 OVERALL CONNECTION DIAGRAM(GUIDE PAGE)
Note: When ordering service parts, be sure to refer to “EXPLODED VIEWS AND PARTS LIST” or “ELECTRICAL PARTS
LIST”.
A
A-a
LOW XOVER
A AMP UNIT
ISOLATOR
GAIN=1 B
HP/LP FILTER
12dB/OCTAVE
NETWORK PCB(A)
40-120Hz
HIGH XOVER
3k-9kHz
BP FILTER
LOW-X TO HIGH-X
NETWORK UNIT
Consists of
• NETWORK PCB
• NETWORK PCB
CN851
Large size
A-a A-b
SCH diagram

CN101

CN102
A-a A-b Guide page
CN851

CN102-2
CN101-2
A-a A-b Detailed page RCA OUT
GAIN=1

CN851

CN851

ISOLATOR
GAIN=1

CN104-2

CN103-2
CN103

CN104

CN852

CN852

C
LOW XOVER
40-120Hz
C NETWORK PCB(B)
HP/LP FILTER
12dB/OCTAVE
HIGH XOVER
3k-9kHz

POWER SUPPLY

D
FAN MOTOR
HXM0001

6 A B C
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A-b A

IT AMP
GAIN=8.5-33dB
CB(A)
CB(B)

CN301

AMP
GAIN=8.5-33dB

CN301

GM-X944/X1R/EW, ES

CN904

CN903

CN902

CN901

D
220
HZS12L(A3)
CN906

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A 8
7
 B
A

D
C

8
A-a A-b

1
1

LOW XOVER
GM-X944

AMP UNIT HP/LP FILTER BP FILTER NETWORK UNIT

A ISOLATOR 40-120Hz
B 12dB/OCTAVE HIGH XOVER LOW-X TO HIGH-X Consists of
GAIN=1
NETWORK PCB(A) 3k-9kHz • NETWORK PCB(A)
• NETWORK PCB(B)

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CN851

A-a B C
CN101
CN102

2
2

manuals search engine

CN851
CN102-2
CN101-2

RCA OUT
GAIN=1

CN851

3
3

1
CN851

ISOLATOR

4
4

GAIN=1

CN852
CN103
CN104
CN104-2
CN103-2
 CN852
5

LOW XOVER
40-120Hz
HP/LP FILTER HIGH XOVER
C NETWORK PCB(B) 12dB/OCTAVE 3k-9kHz

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2

6
6

G
POWER SUPPLY

7
7

3
FAN MOTOR
HXM0001
CN906

8
A-a C
8

A-a A-b

9
GM-X944

D
C
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A-a A-b

CN301

CN301
A GAIN=8.5-33dB

GAIN=8.5-33dB
AMP

AMP
B

D
B(A)
B(B)
T

10 A-b
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CN904

CN903

CN902

CN901

A-a A-b
A

220

HZS12L(A3)
GM-X944/X1R/EW, ES

CN906
2

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A-b 8
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4. PCB CONNECTION DIAGRAM

4.1 AMP UNIT
NOTE FOR PCB DIAGRAMS
A 1. The parts mounted on this PCB
C CN104
include all necessary parts for
several destination.
For further information for
respective destinations, be sure
to check with the schematic
diagram.
2. Viewpoint of PCB diagrams

Connector Capacitor

SIDE A 4CH
†

2CH

P.C.Board Chip Part SIDE B

B

A AMP UNIT

B CN102

12 A
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SIDE A

D
BFC
FAN MOTOR

A 13
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A AMP UNIT

14 A
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SIDE B

A 15
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4.2 NETWORK PCB(A)

B NETWORK PCB(A) SIDE A

A CN101

OFF, LPF, HPF, BPF LOW, HIGH

B NETWORK PCB(A) SIDE B

16 B
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4.3 NETWORK PCB(B)

C NETWORK PCB(B) SIDE A

A CN103

LOW, HIGH OFF, LPF, HPF

C NETWORK PCB(B) SIDE B

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C 4
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5. ELECTRICAL PARTS LIST

NOTE:
- Parts whose parts numbers are omitted are subject to being not supplied.
- The part numbers shown below indicate chip components.
Chip Resistor
RS1/_S___J,RS1/__S___J
Chip Capacitor (except for CQS.....)
CKS....., CCS....., CSZS.....

=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
R 126 RS1/10S103J
Network Unit R 127 RS1/10S472J
Consists of R 128 RS1/10S472J
Network PCB(A) R 129 RS1/10S103J
Network PCB(B) R 130 RS1/10S103J

Unit Number : HWG0020(GM-X944/X1R/UC) R 131 RS1/10S562J

BC : HWG0016(GM-X944/X1R/EW) R
R
132
133
RS1/10S562J
RS1/10S103J
: HWG0021(GM-X944/X1R/ES) R 134 RS1/10S103J
Unit Name : Network Unit R 135 RS1/10S103J

MISCELLANEOUS R 136 RS1/10S103J

R 137 RS1/10S103J
IC 101 IC NJM2068D R 138 RS1/10S103J
IC 102 IC NJM2068D R 143 RS1/10S102J
IC 103 IC NJM2068D R 144 RS1/10S102J
IC 104 IC NJM2068D
IC 105 IC NJM2068D R 145 RS1/10S102J
R 146 RS1/10S102J
IC 106 IC NJM2068D R 147 RS1/10S562J
IC 107 IC NJM2068D R 148 RS1/10S562J
IC 108 IC NJM2068D R 149 RS1/10S103J
S 101 Switch(OFF, LPF, HPF, BPF) HSH0002
S 102 Switch(OFF, LPF, HPF) CSH1029 R 150 RS1/10S103J
R 151 RS1/10S562J
S 103 Slide Switch(LOW, HIGH) CSH1042 R 152 RS1/10S562J
S 104 Slide Switch(LOW, HIGH) CSH1042 R 153 RS1/10S103J
VR 101 Variable Resistor 20kΩ(E) CCS1266 R 154 RS1/10S103J
VR 102 Volume 20kΩ(E) HCS0002
VR 103 Variable Resistor 20kΩ(E) CCS1266 CAPACITORS
RESISTORS C 101 CKSQYB184K16
C 102 CKSQYB184K16
R 101 RS1/10S113J C 103 CKSQYB222K50
R 102 RS1/10S113J C 104 CKSQYB222K50
R 103 RS1/10S113J C 105 CKSQYB823K50
R 104 RS1/10S113J
R 105 RS1/10S822J C 106 CKSQYB823K50
C 107 CKSQYB103K25
R 106 RS1/10S822J C 108 CKSQYB103K25
R 107 RS1/10S822J C 109 CKSQYB122K50
R 108 RS1/10S822J C 110 CKSQYB122K50
R 109 RS1/10S102J
R 110 RS1/10S102J C 111 CKSQYB184K16
C 112 CKSQYB184K16
R 111 RS1/10S182J C 113 CKSQYB184K16
R 112 RS1/10S182J C 114 CKSQYB184K16
R 113 RS1/10S822J C 115 CKSQYB184K16
R 114 RS1/10S822J
R 115 RS1/10S822J C 116 CKSQYB184K16
C 117 CKSQYB184K16
R 116 RS1/10S822J C 118 CKSQYB184K16
R 117 RS1/10S102J C 119 CCSQCH470J50
R 118 RS1/10S102J C 120 CCSQCH470J50
R 119 RS1/10S182J
R 120 RS1/10S182J C 121 CFTLA124J50
C 122 CFTLA124J50
R 121 RS1/10S103J C 123 CKSQYB182K50
R 122 RS1/10S103J C 124 CKSQYB182K50
R 123 RS1/10S103J C 125 CFTLA124J50
R 124 RS1/10S103J
R 125 RS1/10S103J

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=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
C 126 CFTLA124J50 Q 346 Transistor 2SC2240
C 127 CKSQYB182K50 Q 347 Transistor 2SC2240
C 128 CKSQYB182K50 Q 348 Transistor 2SC2240
Q 349 Transistor 2SA970
Unit Number : HWH0134(GM-X944/X1R/UC) Q 350 Transistor 2SA970
A : HWH0123(GM-X944/X1R/EW) Q 351 Transistor 2SA970
: HWH0135(GM-X944/X1R/ES) Q 352 Transistor 2SA970
Unit Name : Amp Unit Q 353 FET 94-4980
Q 354 FET 94-4980
MISCELLANEOUS Q 355 FET 94-4980

IC 201 IC NJM2068D Q 356 FET 94-4980

IC 202 IC NJM2068D Q 357 FET 94-4980
IC 651 IC PA2027A Q 358 FET 94-4980
IC 851 IC NJM2068D Q 359 FET 94-4980
IC 852 IC NJM2068D Q 360 FET 94-4980

IC 853 IC NJM2068D Q 361 FET 94-4981

IC 854 IC NJM2068D Q 362 FET 94-4981
IC 855 IC NJM2068D Q 363 FET 94-4981
IC 901 IC UPC494C Q 364 FET 94-4981
Q 201 Transistor 2SC2458 Q 365 FET 94-4981

Q 202 Transistor 2SC2458 Q 366 FET 94-4981

Q 203 Transistor 2SC2458 Q 367 FET 94-4981
Q 204 Transistor 2SC2458 Q 368 FET 94-4981
Q 205 Transistor DTA124ES Q 653 Transistor 2SA1048
Q 301 Transistor 2SA992 Q 654 Transistor 2SC2458

Q 302 Transistor 2SA992 Q 655 Transistor 2SC2458

Q 303 Transistor 2SA992 Q 657 Transistor 2SA1048
Q 304 Transistor 2SA992 Q 658 Transistor 2SC2458
Q 305 Transistor 2SC1845 Q 659 Transistor 2SA1048
Q 306 Transistor 2SC1845 Q 660 Transistor 2SB1243

Q 307 Transistor 2SC1845 Q 661 Transistor 2SC2458

Q 308 Transistor 2SC1845 Q 663 Transistor 2SD1768S
Q 309 Transistor 2SK389 Q 664 Transistor 2SD1768S
Q 310 Transistor 2SK389 Q 665 Transistor 2SD1768S
Q 311 Transistor 2SK389 Q 666 Transistor 2SD1768S

Q 312 Transistor 2SK389 Q 902 Transistor 2SA1048

Q 313 Transistor 2SC1845 Q 903 Transistor 2SB1277
Q 314 Transistor 2SC1845 Q 904 Transistor 2SB1277
Q 315 Transistor 2SC1845 Q 905 FET STP50NE08
Q 316 Transistor 2SC1845 Q 906 FET STP50NE08

Q 317 Transistor 2SC1845 Q 907 Transistor 2SD2395

Q 318 Transistor 2SC1845 Q 908 Transistor 2SB1566
Q 319 Transistor 2SC1845 Q 909 Transistor 2SD1919
Q 320 Transistor 2SC1845 Q 910 Transistor 2SD1919
Q 321 Transistor 2SA992 Q 911 FET STP50NE08

Q 322 Transistor 2SA992 Q 912 FET STP50NE08

Q 323 Transistor 2SA992 Q 913 FET STP50NE08
Q 324 Transistor 2SA992 Q 914 FET STP50NE08
Q 325 Transistor 2SA992 Q 915 Transistor 2SD1864
Q 326 Transistor 2SA992 Q 916 Transistor 2SC2458

Q 327 Transistor 2SA992 Q 917 Transistor 2SB1243

Q 328 Transistor 2SA992 D 301 Diode HZS6L(C1)
Q 329 Transistor 2SA970 D 302 Diode HZS6L(C1)
Q 330 Transistor 2SA970 D 303 Diode HZS6L(C1)
Q 331 Transistor 2SA970 D 304 Diode HZS6L(C1)

Q 332 Transistor 2SA970 D 313 Diode 1SS133

Q 337 Transistor 2SC2240 D 314 Diode 1SS133
Q 338 Transistor 2SC2240 D 315 Diode 1SS133
Q 339 Transistor 2SC2240 D 316 Diode 1SS133
Q 340 Transistor 2SC2240 D 317 Diode 1SS133

Q 341 Transistor 2SC1845 D 318 Diode 1SS133

Q 342 Transistor 2SC1845 D 319 Diode 1SS133
Q 343 Transistor 2SC1845 D 320 Diode 1SS133
Q 344 Transistor 2SC1845 D 321 Diode RD5R1ES(B2)
Q 345 Transistor 2SC2240 D 322 Diode RD5R1ES(B2)

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=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
D 323 Diode RD5R1ES(B2) R 220 RS1/10S163J
D 324 Diode RD5R1ES(B2) R 221 RS1/10S163J
D 602 LED SML210LT(LMN) R 222 RS1/10S163J
D 651 Diode RM4Z R 301 RS1/10S301J
D 652 Diode RM4Z R 302 RS1/10S301J

D 653 Diode 1SS133 R 303 RS1/10S301J

D 654 Diode HZS7L(B2) R 304 RS1/10S301J
D 655 Diode ERA15-02VH R 305 RS1/10S183J
D 656 Diode ERA15-02VH R 306 RS1/10S183J
D 658 Diode 1SS133 R 307 RS1/10S183J

D 659 Diode 1SS133 R 308 RS1/10S183J

D 661 Diode 1SS133 R 309 RD1/4PU221J
D 662 Diode 1SS133 R 310 RD1/4PU221J
D 663 Diode 1SS133 R 311 RD1/4PU221J
D 664 Diode 1SS133 R 312 RD1/4PU221J

D 665 Diode 1SS133 R 313 RD1/4PU680J

D 907 Diode FML22S R 314 RD1/4PU680J
D 908 Diode HZS16L(1) R 315 RD1/4PU680J
D 909 Diode HZS16L(1) R 316 RD1/4PU680J
D 910 Diode FML22R R 317 RD1/4PU680J

D 912 Diode ALO1ZWS R 318 RD1/4PU680J

D 913 Diode ALO1ZWS R 319 RD1/4PU680J
D 914 Diode ALO1ZWS R 320 RD1/4PU680J
D 915 Diode ALO1ZWS R 321 RD1/4PU332J
D 916 Diode HZS12L(A3) R 322 RD1/4PU332J

L 851 Ferri-Inductor CTF1007 R 323 RD1/4PU332J

L 852 Ferri-Inductor CTF1007 R 324 RD1/4PU332J
L 853 Ferri-Inductor CTF1007 R 325 RD1/4PU101J
L 854 Ferri-Inductor CTF1007 R 326 RD1/4PU101J
L 901 Choke Coil 50mH CTH1144 R 327 RD1/4PU101J

T 901 Transformer HTT0010 R 328 RD1/4PU101J

TH 901 Thermistor CCX1013 R 329 RD1/4PU153J
TH 902 Thermistor CCX1013 R 330 RD1/4PU153J
TH 903 Thermistor CCX1035 R 331 RD1/4PU153J
TH 904 Thermistor CCX1027 R 332 RD1/4PU153J

S 851 Slide Switch(4CH†2CH) CSH1042 R 333 RD1/4PU181J

S 901 Switch(BFC)(GM-X944/X1R/EW, ES) HSH-156 R 334 RD1/4PU181J
VR 201 Variable Resistor 10kΩ(A) CCS1265 R 335 RD1/4PU181J
VR 202 Variable Resistor 10kΩ(A) CCS1265 R 336 RD1/4PU181J
VR 501 Semi-fixed 10kΩ(B) CCP1206 R 337 RD1/4PU432J

VR 502 Semi-fixed 10kΩ(B) CCP1206 R 338 RD1/4PU432J

VR 503 Semi-fixed 10kΩ(B) CCP1206 R 339 RD1/4PU432J
VR 504 Semi-fixed 10kΩ(B) CCP1206 R 340 RD1/4PU432J
FU 902 Fuse 30A HEK0030 R 341 RD1/4PU221J
FU 903 Fuse 30A HEK0030 R 342 RD1/4PU221J

FU 904 Fuse 30A HEK0030 R 343 RD1/4PU221J

Network Unit(GM-X944/X1R/UC) HWG0020 R 344 RD1/4PU221J
Network Unit(GM-X944/X1R/EW) HWG0016 R 345 RD1/4PU471J
Network Unit(GM-X944/X1R/ES) HWG0021 R 346 RD1/4PU471J
R 347 RD1/4PU471J
RESISTORS
R 348 RD1/4PU471J
R 141 RS1/10S222J R 353 RD1/4PU183J
R 142 RS1/10S222J R 354 RD1/4PU183J
R 201 RD1/4PU472J R 355 RD1/4PU183J
R 202 RD1/4PU472J R 356 RD1/4PU183J
R 203 RD1/4PU472J
R 357 RD1/4PU332J
R 204 RD1/4PU472J R 358 RD1/4PU332J
R 211 RD1/4PU111J R 359 RD1/4PU332J
R 212 RD1/4PU111J R 360 RD1/4PU332J
R 213 RD1/4PU111J R 361 RD1/4PU181J
R 214 RD1/4PU111J
R 362 RD1/4PU181J
R 215 RS1/10S202J R 363 RD1/4PU181J
R 216 RS1/10S202J R 364 RD1/4PU181J
R 217 RS1/10S202J R 369 RD1/4PU163J
R 218 RS1/10S202J R 370 RD1/4PU163J
R 219 RS1/10S163J

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=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
R 371 RD1/4PU163J R 606 RD1/4PU561J
R 372 RD1/4PU163J R 656 RD1/4PU473J
R 373 RD1/4PU121J R 657 RD1/4PU104J
R 374 RD1/4PU121J R 658 RD1/4PU472J
R 375 RD1/4PU121J R 659 RD1/4PU103J

R 376 RD1/4PU121J R 660 RD1/4PU102J

R 377 RD1/4PU102J R 661 RD1/4PU472J
R 378 RD1/4PU102J R 662 RD1/4PU222J
R 379 RD1/4PU102J R 663 RD1/4PU563J
R 380 RD1/4PU102J R 664 RD1/4PU222J

R 381 RD1/4PU622J R 665 RD1/4PU103J

R 382 RD1/4PU622J R 666 RD1/4PU103J
R 383 RD1/4PU622J R 667 RD1/4PU222J
R 384 RD1/4PU622J R 668 RD1/4PU472J
R 389 RD1/4PU104J R 671 RD1/4PU221J

R 390 RD1/4PU104J R 672 RD1/4PU152J

R 391 RD1/4PU104J R 676 RD1/4PU221J
R 392 RD1/4PU104J R 678 RD1/4PU472J
R 393 RD1/4PU101J R 679 RD1/4PU101J
R 394 RD1/4PU101J R 680 RD1/4PU472J

R 395 RD1/4PU101J R 681 RD1/4PU682J

R 396 RD1/4PU101J R 682 RD1/4PU682J
R 397 RD1/4PU102J R 683 RD1/4PU103J
R 398 RD1/4PU102J R 684 RD1/4PU223J
R 399 RD1/4PU102J R 685 RD1/4PU223J

R 400 RD1/4PU102J R 686 RD1/4PU223J

R 401 RD1/4PU101J R 687 RD1/4PU563J
R 402 RD1/4PU101J R 688 RD1/4PU563J
R 403 RD1/4PU101J R 689 RD1/4PU563J
R 404 RD1/4PU101J R 690 RD1/4PU563J

R 405 RS1/10S101J R 691 RD1/4PU563J

R 406 RS1/10S101J R 692 RD1/4PU563J
R 407 RS1/10S101J R 693 RD1/4PU563J
R 408 RS1/10S101J R 694 RD1/4PU563J
R 409 RS1/10S101J R 695 RD1/4PU564J

R 410 RS1/10S101J R 696 RD1/4PU564J

R 411 RS1/10S101J R 697 RD1/4PU564J
R 412 RS1/10S101J R 698 RD1/4PU564J
R 413 RS1/10S101J R 699 RD1/4PU473J
R 414 RS1/10S101J R 700 RD1/4PU473J

R 415 RS1/10S101J R 701 RD1/4PU473J

R 416 RS1/10S101J R 702 RD1/4PU473J
R 417 RS1/10S101J R 703 RS1/2PMF100J
R 418 RS1/10S101J R 704 RS1/2PMF100J
R 419 RS1/10S101J R 705 RS1/2PMF100J

R 420 RS1/10S101J R 706 RS1/2PMF100J

R 421 SPR30R1J R 851 RS1/10S471J
R 422 SPR30R1J R 852 RS1/10S471J
R 423 SPR30R1J R 853 RS1/10S471J
R 424 SPR30R1J R 854 RS1/10S471J

R 425 SPR30R1J R 855 RS1/10S223J

R 426 SPR30R1J R 856 RS1/10S223J
R 427 SPR30R1J R 857 RS1/10S223J
R 428 SPR30R1J R 858 RS1/10S223J
R 429 SPR30R1J R 859 RN1/10SE1002D

R 430 SPR30R1J R 860 RN1/10SE1002D

R 431 SPR30R1J R 861 RN1/10SE1002D
R 432 SPR30R1J R 862 RN1/10SE1002D
R 433 SPR30R1J R 863 RN1/10SE1002D
R 434 SPR30R1J R 864 RN1/10SE1002D

R 435 SPR30R1J R 865 RN1/10SE1002D

R 436 SPR30R1J R 866 RN1/10SE1002D
R 467 RS1/10S122J R 871 RN1/10SE1002D
R 468 RS1/10S122J R 872 RN1/10SE1002D
R 605 RD1/4PU561J R 873 RN1/10SE1002D

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 GM-X944

=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
R 874 RN1/10SE1002D C 302 CEJANP100M16
R 875 RN1/10SE1002D C 303 CEJANP100M16
R 876 RN1/10SE1002D C 304 CEJANP100M16
R 877 RN1/10SE1002D C 305 CMA220J2H
R 878 RN1/10SE1002D C 306 CMA220J2H

R 879 RS1/10S223J C 307 CMA220J2H

R 880 RS1/10S223J C 308 CMA220J2H
R 883 RS1/10S821J C 309 CQMA152J50
R 884 RS1/10S821J C 310 CQMA152J50
R 885 RS1/10S472J C 311 CQMA152J50

R 886 RS1/10S222J C 312 CQMA152J50

R 887 RS1/10S472J C 313 CQMA103J50
R 889 RS1/10S472J C 314 CQMA103J50
R 901 (GM-X944/X1R/EW, ES) RD1/4PU105J C 315 CQMA103J50
R 902 RS1/2PMF220J C 316 CQMA103J50

R 907 RS1/10S473J C 317 CMA030D2H

R 909 RS1/2PMF220J C 318 CMA030D2H
R 910 RS1/10S153J C 319 CMA030D2H
R 911 RS1/10S102J C 320 CMA030D2H
R 912 RD1/4PU272J C 321 CMA180J2H

R 913 RS1/10S472J C 322 CMA180J2H

R 914 RS1/10S472J C 323 CMA180J2H
R 915 RS1/10S472J C 324 CMA180J2H
R 916 RD1/4PU332J C 325 100µF/16V HCH0002
R 917 RD1/4PU332J C 326 100µF/16V HCH0002

R 918 RS1/2PMF220J C 327 100µF/16V HCH0002

R 919 RS1/2PMF220J C 328 100µF/16V HCH0002
R 920 RD1/4PU472J C 329 CFTLA393J50
R 921 RD1/4PU472J C 330 CFTLA393J50
R 922 RD1/4PU472J C 331 CFTLA393J50

R 923 RD1/4PU472J C 332 CFTLA393J50

R 924 RS1/2PMF121J C 333 CEAS100M50
R 925 RS1/2PMF121J C 334 CEAS100M50
R 926 RS1/2PMF121J C 335 CEAS100M50
R 927 RS1/2PMF121J C 336 CEAS100M50

R 928 RS1/2PMF121J C 337 CEAS470M50

R 929 RS1/2PMF121J C 338 CEAS470M50
R 932 RD1/4PU104J C 339 CEAS470M50
R 935 RS1/10S202J C 340 CEAS470M50
R 936 RS1/10S223J C 345 CFTLA333J50

R 937 RS1/10S103J C 346 CFTLA333J50

R 938 RD1/4PU272J C 347 CFTLA333J50
R 939 RD1/4PU272J C 348 CFTLA333J50
R 947 RS1/2PMF100J C 349 CQMA102J50
R 948 RS1/2PMF100J C 350 CQMA102J50

R 949 RD1/4PU113J C 351 CQMA102J50

R 950 RS1/10S101J C 352 CQMA102J50
R 951 RD1/4PU752J C 357 CMA030D2H
R 952 RS1/2PMF560J C 358 CMA030D2H
R 953 RS1/2PMF560J C 359 CMA030D2H

R 954 RD1/4PU221J C 360 CMA030D2H

R 955 RS1/10S393J C 361 CMA680J2H
R 956 RS1/10S472J C 362 CMA680J2H
R 957 RS1/10S222J C 363 CMA680J2H
C 364 CMA680J2H
CAPACITORS
C 365 CMA680J2H
C 201 CCSQCH820J50 C 366 CMA680J2H
C 202 CCSQCH820J50 C 367 CMA680J2H
C 203 CCSQCH820J50 C 368 CMA680J2H
C 204 CCSQCH820J50 C 457 CEJA101M16
C 205 CEJA470M16
C 458 CEJA101M16
C 206 CEJA470M16 C 651 220µF/10V CCH1036
C 207 CEJA470M16 C 652 CFTLA103J50
C 208 CEJA470M16 C 653 CEAS100M16
C 209 CKSQYB102K50 C 654 CEAS100M16
C 301 CEJANP100M16

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 GM-X944

=====Circuit Symbol and No.===Part Name Part No. =====Circuit Symbol and No.===Part Name Part No.
--- ------ ------------------------------------------ ------------------------- --- ------ ------------------------------------------ -------------------------
C 655 CFTLA103J50 C 918 337RZM050M1020
C 656 470µF/16V CCH1183 C 919 337RZM050M1020
C 657 CKSQYB223K50 C 920 337RZM050M1020
C 658 CEAS220M16 C 921 337RZM050M1020
C 659 470µF/16V CCH1183 C 922 CFTLA224J50

C 660 CFTLA105J50 C 923 CFTLA224J50

C 661 CFTLA103J50 C 924 CFTLA564J50
C 662 CFTLA103J50 C 925 CCG-081
C 663 CFTLA334J50 C 926 CCG-081
C 664 CKSQYB223K50 C 927 CQMA102J50

C 665 CKSQYB223K50 C 930 337RZM050M1020

C 666 CKSQYB223K50 C 931 337RZM050M1020
C 851 CEAS100M16 C 932 CEAS470M10
C 852 CEAS100M16 C 933 CEAS101M16
C 853 CEAS100M16 C 934 CEAS101M16

C 854 CEAS100M16 C 935 CKSQYB102K50

C 855 CQMA472J50 C 936 CKSQYB102K50
C 856 CQMA472J50 C 941 CKSQYB473K50
C 857 CQMA472J50 C 942 CKSQYB473K50
C 858 CQMA472J50 C 943 CKSQYB223K50

C 859 CCSQCH470J50 C 946 CFTNA104J50

C 860 CCSQCH470J50 C 947 CFTNA104J50
C 861 CCSQCH470J50
C 862 CCSQCH470J50 Miscellaneous Parts List
C 863 CCSQCH470J50
Fan Motor HXM0001
C 864 CCSQCH470J50
C 865 CCSQCH470J50
C 866 CCSQCH470J50
C 875 CKSQYB471K50
C 876 CKSQYB471K50

C 877 CKSQYB471K50
C 878 CKSQYB471K50
C 879 CKSQYB471K50
C 880 CKSQYB471K50
C 881 CEAS4R7M35

C 882 CEAS4R7M35
C 883 CCSQCH470J50
C 885 CKSQYB473K50
C 886 CKSQYB473K50
C 887 CKSQYB473K50

C 888 CKSQYB473K50
C 889 CKSQYB473K50
C 890 CKSQYB473K50
C 891 CKSQYB473K50
C 892 CKSQYB473K50

C 893 CCSSL101J50
C 894 CCSSL101J50
C 895 CCSSL101J50
C 896 CCSSL101J50
C 902 CEAS221M10

C 903 CEAS2R2M50
C 904 CEAS101M16
C 905 CQMA472J50
C 906 CQMA472J50
C 907 4700µF/16V CCH1310

C 908 4700µF/16V CCH1310

C 909 4700µF/16V CCH1310
C 910 478LBA050M2DC
C 911 478LBA050M2DC
C 912 478LBA050M2DC

C 913 478LBA050M2DC
C 914 CQMA102J50
C 915 CQMA102J50
C 916 CEASR10M50
C 917 CEASR10M50

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 GM-X944

6. ADJUSTMENT
- Setting Idle Current
The following is the instructions for setting Idle current:

Setting the idle current to the following ranges will require you
to measure the voltage across the indicated resistors and adjusting
the indicated variable resistors to set the required voltage range.
This adjustment is performed with no loads on the outputs with no
signal input.

Specification: 45 mA ± 5mA
Voltage Range: 4.0 mV to 5.0 mV

1. Measure voltage across Resistor R433 and set VR501 to Voltage Range.
2. Measure voltage across Resistor R434 and set VR502 to Voltage Range.
3. Measure voltage across Resistor R435 and set VR503 to Voltage Range.
4. Measure voltage across Resistor R436 and set VR504 to Voltage Range.

Notes:

The Idle current should be set when the amplifier has not been run for awhile,
and set at room temperature.

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 GM-X944

7. GENERAL INFORMATION
7.1 DISASSEMBLY
- Removing the Case and the Plate (Fig.1) Case
Connector

Remove the six screws.

Remove the screw.

Remove the three screws.

Remove the six screws.

Disconnect the connector and then remove the Case.

Remove the screw and then remove the

Plate.

Fig.1

Plate

- Removing the Amp Unit (Fig.2)

Remove the two screws.

Remove the two screws.

Remove the eight screws and then remove

the Amp Unit.

Amp Unit Fig.2

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 GM-X944

8. OPERATIONS AND SPECIFICATIONS

8.1 OPERATIONS

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 Gain Control Power Indicator
Adjusting the gain controls A and B will The power indicator lights when the
help match the output of the car stereo to power is switched on.
the Pioneer amplifier. Normally, set the
gain controls to the “NORMAL”
position. If the output is low, even when
the volume of the car stereo is turned up,
turn these controls clockwise. If there is
distortion when the volume of the car
stereo is turned up, turn these controls
counter-clockwise.
• If you only use one input plug, set the gain

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controls for speaker outputs A and B to the
same position.
• When using with an RCA equipped car
stereo (standard output of 500 mV), set to
the NORMAL position. When using with
an RCA equipped Pioneer car stereo with
max. output of 4 V or more, adjust level to
match the car stereo output level.

LPF (Low-Pass Filter)/HPF (High-Pass Filter)/BPF (Band-Pass Filter) and

LOW/HIGH Select Switch
Set the LPF/HPF/BPF and LOW/HIGH select switch as follows according to the type of
speaker that is connected to the speaker output connector and the car stereo system:

LPF/HPF/BPF Audio frequency range Speaker Remarks

and LOW/HIGH to be output Type
Select Switch
LPF HIGH — 3k to 9k Hz Mid Connect a mid range speaker.
LOW — 40 to 120 Hz Subwoofer Connect a subwoofer.
HPF HIGH *2 3k to 9k Hz — Tweeter*3 Connect a tweeter.
Cut Off Frequency Control LOW 40 to 120 Hz — Full range Use if you want to cut the
very low frequency range
Combining LPF/HPF/BPF and because it is not necessary
LOW/HIGH select switch settings lets for the speakers you are
you select between cut off frequencies using.
from 40 to 120 Hz and 3k to 9k Hz. BPF (for CH A)*4 40 to 120 Hz — Mid Connect a mid range speaker.
(Example: LPF and HIGH)
— 3k to 9k Hz
(dB) (3 kHz) (9 kHz)
OFF Full range Full range
0
-3 RCA Input Select Switch *2 With CH A, even if the setting is HPF-HIGH, you can only select the same cut off frequency as with
Level HPF-LOW (40 to 120 Hz).
For two-channel input, slide this switch
*3 If you connect the tweeter directly, you must set the CH B to HPF-HIGH.
to the left. For four-channel input, slide *4 Be sure to set the LOW/HIGH select switch to HIGH.
Frequency (Hz) this switch to the right.

27
GM-X944
 GM-X944

Connection Diagram
Fuse (30 A) × 2
Grommet Special red battery wire [RD-223] (sold separately).
After making all other connections at the amplifier,
connect the battery wire terminal of the amplifier to
the positive (+) terminal of the battery.

Fuse (30 A) × 2 Ground wire (black) [RD-223] (sold separately).

Connect to metal body or chassis.

RCA input Amplifier with

RCA input jacks
Connecting wires with RCA pin
plugs (sold separately).

Car stereo with

RCA output jacks
External Output
For details on how to connect to RCA
input jacks A and B, see the
“Connecting the Speakers and Input
wires” section.

Front side

RCA output jack RCA input jack B

RCA input jack A

Connecting wires with RCA pin

plugs (sold separately).
Back side

Fuse (30 A) × 3

Speaker output terminal

System remote control wire (sold separately)
Connect the male terminal of this wire to the system remote control
terminal of the car stereo (SYSTEM REMOTE CONTROL). The
female terminal can be connected to the auto-antenna relay control
terminal. If the car stereo does not have a system remote control
terminal, connect the male terminal to the power terminal through
the ignition switch.

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 GM-X944

8.2 SPECIFICATIONS
- GM-X944/X1R/UC

Power source .............................................................................................................. 14.4 V DC (10.8 — 15.1 V allowable)

Grounding system ............................................................................................................................................ Negative type
Current consumption ........................................................................................................ 43.7 A (at continuous power, 4 Ω)
Average current drawn* ........................................................................................................ 14.5 A (4 Ω for four channels)
26.5 A (4 Ω for two channels)
Fuse ............................................................................................................................................................................ 30 A × 3
Dimensions .......................................................................................................................... 270 (W) × 60 (H) × 297 (D) mm
[10-5/8 (W) × 2-3/8 (H) × 11-3/4 (D) in]
Weight ........................................................................................................ 5.4 kg (11.9 lbs) (Leads for wiring not included)
Maximum power output .................................................................................................................... 150 W × 4 / 500 W × 2
Continuous power output ............................................................ 75 W × 4 (at 14.4 V, 4 Ω, 20 — 20,000 Hz, 0.04% THD)
250 W × 2 (at 14.4 V, 4 Ω, 20 — 20,000 Hz, 0.4% THD)
125 W × 4 (at 14.4 V, 2 Ω, 20 — 20,000 Hz, 0.4% THD)
Load impedance .............................................................................................................................. 4 Ω (1 — 8 Ω allowable)
(Bridge connection: 2 — 8 Ω allowable)
Frequency response ............................................................................................................ 10 — 50,000 Hz (+0 dB, –1 dB)
Signal-to-noise ratio ...................................................................................................................... 105 dB (IHF–A network)
Distortion ............................................................................................................................................ 0.005% (10 W, 1 kHz)
Separation ........................................................................................................................................................ 65 dB (1 kHz)
Variable crossover network
A CH: LPF-L/LPF-H/HPF-L/BPF
B CH: LPF-L/LPF-H/HPF-L/HPF-H
Cut off frequency .................................................................................................... Low frequency: 40 — 120 Hz
High frequency: 3k — 9k Hz
Cut off slope .......................................................................................................................................... –12 dB/oct
Maximum input level/impedance .................................................................................... RCA: 6.5 V/22 kΩ (0.4 — 6.5 V)
Note:
• Specifications and the design are subject to possible modification without notice
due to improvements.
*Average current drawn
• The average current drawn is nearly the maximum current drawn by this unit when
an audio signal is input. Use this value when working out total current drawn by
multiple power amplifiers.

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 GM-X944

- GM-X944/X1R/EW

Power source .......................................................................................................... 14.4 V DC (10.8 — 15.1 V allowable)

Grounding system .......................................................................................................................................... Negative type
Current consumption .................................................................................................... 43.7 A (at continuous power, 4 Ω)
Average current drawn* ...................................................................................................... 14.5 A (4 Ω for four channels)
26.5 A (4 Ω for two channels)
Fuse ........................................................................................................................................................................ 30 A × 3
Dimensions ...................................................................................................................... 270 (W) × 60 (H) × 297 (D) mm
Weight .................................................................................................................... 5.4 kg (Leads for wiring not included)
Maximum power output .................................................................................................................. 150 W × 4 / 500 W × 2
Continuous power output .......................................................... 75 W × 4 (at 14.4V, 4 Ω, 20 — 20,000Hz, 0.04% THD)
250 W × 2 (at 14.4V, 4 Ω, 20 — 20,000Hz, 0.4% THD)
125 W × 4 (at 14.4V, 2 Ω, 20 — 20,000Hz, 0.4% THD)
115 W × 4 / 360 W × 2 (DIN45324, +B=14.4 V)
Load impedance .......................................................................................................................... 4 Ω (1 — 8 Ω allowable)
(Bridge connection: 2 — 8 Ω allowable)
Frequency response .......................................................................................................... 10 — 50,000 Hz (+0 dB, –1 dB)
Signal-to-noise ratio .................................................................................................................... 105 dB (IEC-A network)
Distortion .......................................................................................................................................... 0.005% (10 W, 1 kHz)
Separation ...................................................................................................................................................... 65 dB (1 kHz)
Varibale crossover network
A CH: LPF-L/LPF-H/HPF-L/BPF
B CH: LPF-L/LPF-H/HPF-L/HPF-H
Cut off frequency ................................................................................................ Low frequency: 40 — 120 Hz
High frequency: 3k — 9k Hz
Cut off slope ...................................................................................................................................... –12 dB/oct
Maximum input level/impedance .................................................................................. RCA: 6.5 V/22 kΩ (0.4 — 6.5 V)
Note:
• Specifications and the design are subject to possible modification without notice
due to improvements.
*Average current drawn
• The average current drawn is nearly the maximum current drawn by this unit
when an audio signal is input. Use this value when working out total current
drawn by multiple power amplifiers.

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 GM-X944

- GM-X944/X1R/ES

Power source .............................................................................................................. 14.4 V DC (10.8 — 15.1 V allowable)

Grounding system ............................................................................................................................................ Negative type
Current consumption ........................................................................................................ 43.7 A (at continuous power, 4 Ω)
Average current drawn* ........................................................................................................ 14.5 A (4 Ω for four channels)
26.5 A (4 Ω for two channels)
Fuse ............................................................................................................................................................................ 30 A × 3
Dimensions .......................................................................................................................... 270 (W) × 60 (H) × 297 (D) mm
Weight ........................................................................................................................ 5.4 kg (Leads for wiring not included)
Maximum power output .................................................................................................................... 150 W × 4 / 500 W × 2
Continuous power output ............................................................ 75 W × 4 (at 14.4 V, 4 Ω, 20 — 20,000 Hz, 0.04% THD)
250 W × 2 (at 14.4 V, 4 Ω, 20 — 20,000 Hz, 0.4% THD)
125 W × 4 (at 14.4 V, 2 Ω, 20 — 20,000 Hz, 0.4% THD)
Load impedance .............................................................................................................................. 4 Ω (1 — 8 Ω allowable)
(Bridge connection: 2 — 8 Ω allowable)
Frequency response ............................................................................................................ 10 — 50,000 Hz (+0 dB, –1 dB)
Signal-to-noise ratio ........................................................................................................................ 105 dB (IEC-A network)
Distortion ............................................................................................................................................ 0.005% (10 W, 1 kHz)
Separation ........................................................................................................................................................ 65 dB (1 kHz)
Variable crossover network
A CH: LPF-L/LPF-H/HPF-L/BPF
B CH: LPF-L/LPF-H/HPF-L/HPF-H
Cut off frequency .................................................................................................... Low frequency: 40 — 120 Hz
High frequency: 3k — 9k Hz
Cut off slope .......................................................................................................................................... –12 dB/oct
Maximum input level/impedance .................................................................................... RCA: 6.5 V/22 kΩ (0.4 — 6.5 V)
Note:
• Specifications and the design are subject to possible modification without notice
due to improvements.
*Average current drawn
• The average current drawn is nearly the maximum current drawn by this unit when
an audio signal is input. Use this value when working out total current drawn by
multiple power amplifiers.

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