R446
56K
R445
56K
D420
1N4148
D419
1N4148
+18V
SUPPLY CIR.
+5V
C219
22n 10% 63V
RCA34D
MAIN-IN R-CH
L OUT
R OUT
D412
1N4148
D413
1N4148
+37V
R450
10K
R449
10K
R454
500
R455
500
+37V
Q416
C1815
Q417
C1815
2
3
1
8
4
IC3A
TL082CP/D
R156
470K
R157
470K
C122
1uF,63V,5%
R11
470
C121
1uF,63V,5%
C11
10u/16V
R15
22K
R14
100
Q12
A970
R158
2.2K
Q13
C2240
C12
470p
-18V
+18V
R19
39K,MF,5%
R111
82,MF,5%
R112
82,MF,5%
R110
39k,MF,5%
C14
10u/35V
C13
10u/35V
Q14
C2240
Q15
A970
R115
33
R116
33
Q16
A1015
Q17
C1815
R119
82,MF,5%
R120
82,MF,5%
C18
22p
C19
22p
C15
220uF
/63V
C16
220uF/63V
Q110
KSA1220
Q111
KSC2690
R124
3.
3/
0.
5W
F
P
R125
3.
3/
0.
5W
F
P
R128
330/0.5W FP
R129
330/0.5W FP
R123
47K,5%,1/4
C110
47u/25V
C111
47u/25V
R126
2K7/2W FP
R127
2K7/2W FP
R130
82/1W FS
R131
82/1W FS
R142
22,MF,5%
R143
22,MF,5%
R136
10
R137
10
Q112
KSC2690
Q
115
2SC5200
Q114
2SA1943
Q113
KSA1220
R144
0.068/3W CE
R145
0.068/3W CE
R139
470
R149
160/
1/
4W
1%
C116
2200u/
6.
3V
C117
0.
1u 10% 63V
L11
1uH
R150
1/1W FP
R151
10/1W FS
C118
0.1u 10% 63V
C115
0.1u 10% 63V
C114
0.1u 10%
Q19
D667
Q18
B647
D13
1N4148
D15
1N4148
D14
1N4148
D16
1N4148
R121
100K,MF,5%
R122
100K,
MF
,5
%
R21
470
R12
220K
R22
220K
C112
470p,100V,20%
C113
470p,100V,20%
R147
1K
Q11
C1815
Q12/1
A1015
R152
22K
R12/1
6K8
R148
15K
C120
22n 10%
D17
1N4148
RCA34C
MAIN-IN L-CH
R146
4K3 1W 1%
R154
10
R155
10
Q116
KSC2690
R138
390
Q47
A1015
Q45
A1015
Q46
C1815
R417
100
R419
100
R418
100
R416
100
C415
10u/25V
C416
10u/25V
R422
1.1K
R423
1.1K
R424
1.3K
R425
1.3K
R420
36K
R421
36K
D411
20V
D410
20V
1
2
3
S41A
4
5
6
S41B
ON
OFF
TP4
TP3
FS
FS
C720BEE POWER AMP CIR. R
63V
-18V
+18V
+46V
-46V
+46V
-46V
D11
4.7V
D12
4.7V
R103
82,MF,5%
Q103
C2240
C103
100uF/16V
R101
39k,MF,5%
R106
82,
MF
,5
%
Q104
A970
C104
100uF/16V
R105
39k,MF,5%
R104
220k,
MF
,5
%
R102
220k,
MF
,5
%
Q101
C2240
Q102
A970
R108
39,MF,5%
R107
39,MF,5%
Q48
C1815
C17
0.1uF/63V
C12/1
47uF/25V
R45
33/0.5W FS
R41
680
R43
680
R47
680
C43
220u/50V
C413
220u/35V
Q41
2SD669A
C45
22p
R49
680
R411
680
R413
680
D49
18V
C47
47u/25V
C49
47u/25V
R414
2K2
R46
33 / 0.5W FS
R42
680
R44
680
R48
680
C44
220u/50V
C414
220u/35V
Q43
C1815
C46
22p
R410
680
C48
10u/25V
C410
47u/25V
R412
2K
Q42
2SB649A
Q44
A1015
C411
0.1uF
C412
0.1u 10% 63V
R428
2K2
R429
5K1
MF
MF
-37V
+37V
+18V
-18V
R427
22/1W FP
Q413
D669
Q414
C1815
+37V
+12V
R401
4K7
D403
1N4148
STANDBY
Q421
C1815
R469
10K
R468
22K
R467
T0=80 degree C
D428
1N4148
+18V
R12/2
22K
C422
330u/16V
C421
4u7/50V
C432
0.22u
R441
15K
R442
56K
C420
100u/16V
PROTECTION CIR.
0V
0V
+3.25V
+2.16V
0V
0V
+2.0V
+46V
1
2
3
4
CB49
4PIN
-46V
+46V
1
2
3
CB45
R453
220/2W FP
R452
220/2W FP
R438
22K
R439
T0=90 degree C
Q412
C1815
POSISTOR
+18V
1
2
3
4
5
6
7
8
IC44
UPC1237HA
D42
1N4148
D43
1N4148
R437
47K
STANDBY
R440
2K2
+18V
R478
100K
1
2
3
IC43A
TL082D
R480
6K2
R482
4K7
R479
100K
C428
10u/25V
C425
10u/25V
R470
10K
R471
10K
D418
1N4148
D417
1N4148
R477
47K
R483
330K
R473
47K
R472
470K
C426
10u/25V
C429
10u/25V
R488
39K
R487
39K
R486
560K
R474
1K
C430
10u/25V
R476
1K
C431
10u/25V
R490
100K
R491
100K
4
5
6
7
8
IC43B
TL082D
+18V
+18V
-18V
ISC CIRCUIT
VR12
300
1
2
3
4
5
6
7
8
9
10
CB47
10PIN
I-V
AC DET.
ISC TRIG
VFD AC2
VFD AC1
6
6
5
5
4
4
3
3
2
2
1
1
RL12/2
6
6
5
5
4
4
3
3
2
2
1
1
RL12/1
C435
1nF
C436
1nF
R494
10k
R493
10k
C443
0.1uF
R OUT
L OUT
HEADPHONE OUT L
HEADPHONE OUT R
JK41
1
2
3
CZ45
PHONES SOCKET
N8C320D03
R458
100,FP ,5%,2W
R459
100,FP ,5%,2W
C41
0.1uF
HEADPHONE OUT CIRCUIT FOR Vm1.7
C119
22n 10% 63V
C21
10u/16V
R25
22K
R24
100
Q22
A970
Q23
C2240
C22
470p,50V,20%
R29
39k,MF,5%
R211
82,MF,5%
R212
82,
MF
,5
%
R210
39k,MF,5%
C24
10u/35V
C23
10u/35V
Q24
C2240
Q25
A970
R215
33
R216
33
R203
82,
MF
,5
%
Q26
A1015
Q27
C1815
R219
82,MF,5%
R220
82,MF,5%
C28
22p
C29
22p
C25
220uF
/63V
C26
220uF
/63V
Q210
KSA1220
Q
211
KSC2690
R224
3.
3/
0.
5W
F
P
R225
3.
3/
0.
5W
R228
330/
0.
5W
F
P
R229
330/
0.
5W
R223
47K
C210
47u/25V
C211
47u/25V
R226
2K7/2W
R227
2K7/2W
R230
82/1W FS
R231
82/1W FS
R242
22,MF,5%
R243
22,MF,5%
R236
10
R237
10
Q212
KSC2690
Q
215
2SC5200
Q214
2SA1943
Q213
KSA1220
R244
0.068/3W CE
R245
0.068/3W CE
R239
470
R249
160 1/
4 1% MF
C216
2200u/
6.
3V
C217
0.
1u 10% 63V
L21
1uH
R250
1/1W FP
R251
10/1W FS
C218
0.1u 10% 63v
C215
0.1u 10%
C214
0.1u 10% 63V
TP1
Q29
D667
Q28
B647
D23
1N4148
D25
1N4148
D24
1N4148
D26
1N4148
R221
100K,MF
R222
100K,
MF
,5
%
C212
470p,100V,20%
C213
470p,100V,20%
R247
1K
R248
15K
R252
22K
Q21
C1815
C220
22n 10%
D27
1N4148
R246
4K3/
1W
1% MF
R254
10
R255
10
Q216
KSC2690
R238
390
FP
TP2
FP
FP
FP
FS
FS
63V
Q203
C2240
C203
100uF/16V
R201
39K,MF,5%
R206
82,
MF
,5
%
R205
39k,MF,5%
C204
100uF/16V
Q204
A970
+18V
-18V
+46V
-46V
R202
220k,
MF
,5
%
R204 220k,
MF
,5
%
D21
4.7V
D22
4.7V
Q201
C2240
Q202
A970
R207
39,MF,5%
R208
39,MF,5%
C27
0.1uF/63V
6
5
7
4
8
IC4B
TL082CP/D
R256
470K
R257
470K
C222
1uF,63V,5%
C221
1uF,63V,5%
R258
2.2k
-18V
+18V
VR22
300
POWER AMP CIR. R
POSISTOR
Binding Posts B
Binding Posts A
SPK B
PROTECTION
SPK A
-30V
VFD AC2
VFD AC1
+
18V
-18V
+
12V
+5
V
Name
C720BEE PREAMP Vm1.2.SCH
ISC Circuit:
It switches the power
supply to a lower
voltage when the load
impedance is low, or
the temperature on
the heatsink is over
80C degrees.
Mount on the heatsink
I/V For
Over
Current
Protection
+18V
-18V
+12V
+5V
-30V
-37V
+37V
PCB-10: HEADPHONE BOARD FOR Vm5.0
POWER AMP CIRCUIT FOR Vm1.7
PCB-1:MAIN BOARD FOR Vm5.0
SCHEMATIC DIAGRAM (1/4)
SUBOUT 1
SUBOUT 2
1
2
J204
2PIN
1
2
J204
2PIN
- 18 -
Over Heat Protection:
It shuts down the unit
when the temperature on
the heatsink is over 90C
degrees.
It also shuts down the unit
when the unit enters the
standby mode.
