Download QUAD 405 Evolution - Keith

F1
QUAD 405 Evolution
September 2011
+
R7
3.3k
C5
100u
R14
560R
D1
R6
330k
Input
C1
680n
R3
22k
2
IC1
R4
10k
R1
220k
3
-
R10
1k
8
6
LM301A
+
C7
330p
R17
3.3k
C8
120p
R23
3.3k
C11
330p
C9
330p
Tr2
ZTX304
+
C3
3.3p
C2
100u
3V
C6
1n
R20 1k
R16
180R
R2
R21 1k
R27
8.2k
Tr9
BDY77
R38
47R
L2
3u
Output
C12
100n
Dumpers-out
+
R25
22R
D4
IS920
R37
22R
Tr8
40872
D2
LR120C
First Production PCB M12368 iss. 5 ?
R30
560R
R31
560R
R29
8.2k
L1
6.8u
+
C10
47u
C14
10,000u
Tr10
BDY77
R33
22R
F2
4A
R5
d.c. feedback
10k
QUAD 405 Schematic as published in Wireless World Dec.1975
to support the article “Current Dumping Audio Amplifier”
by P J Walker ot the Acoustic Manufacturing Co. Ltd. (Q.U.A.D.)
Revision: 2
[email protected]
Page Size: A4
QUAD 405 M12333 iss. 2
2 Mar 2002
Drawn: K. Snook
Checked:
SK2
R39
10R
R36
0.08R
R28
75R
Tr6
BC214C
2.2R
R8
3.3k
red
R40
2.7k
2W
D5
IS920
D6
IS920
ClassA-out
R12
3.3k
1
4
D8
Tr7
40872
C13
10,000u
R19
3.3k
C4
47n
7
Tr4
ZTX504
Tr3
ZTX504
R13
22k
D3
IS920
R24
22R
+
R11
1.8k
R9
180R
Tr5
BC214C
R22
270R
Tr1
BC214C
LR120C
R11 is Limiter
for ESL57
Speakers
R18
3.3k
R15
100R
+50V
4A
R35
0.08R
R26
75R
Page 1 of 1
-50V
FS1
+
R7
3.3k
C5
100u
R14
560R
D1
LR120C
Input
C1
680n
R3
22k
2
IC1
R4
22k
R1
220k
3
-
6
C11
330p
R12
3.3k
R17
3.3k
Tr2
ZTX304
C8
120p
+
C3
3.3p
C2
100u
3V
R20 1k
C6
1n
R16
180R
R2
R21 1k
D6
IS920
Tr9
BDY77
R38
47R
Output
C12
100n
Dumpers-out
C10
47u
D4
IS920
Tr8
40872
R30
560R
R31
560R
R37
22R
L1
6.8u
Tr10
BDY77
R29
8.2k
R33
22R
Note: This point is
connected to input
ground but ideally
should be connected
to other side of R2
FS2
d.c. feedback
4.7k
M12368 iss. 7 PCBs were used for serial numbers from ?? to 9000
[email protected]
Revision: 1
Page Size: A4
QUAD 405 - M12333 iss. 3
8 Feb 2003
Drawn:
K. Snook
Checked:
C14
10,000u
C18
47n
4A
R5
+
D2
LR120C
R25
22R
Speaker
R39
10R
R36
0.08R
R28
75R
Tr6
BC214C
+
R8
3.3k
red
R40
2.7k
2W
R27
8.2k
L2
3u
10R
Input ground must
be connected to
chassis at DIN socket
to prevent oscillation
see - R39 C12
D8
D5
IS920
ClassA-out
1
4
Tr7
40872
Tr4
ZTX504
Tr3
ZTX504
R23
1.2k
R10
1k
8
D3
IS920
C13
10,000u
C7
330p
7
R24
22R
R13
22k
C4
47n
LM301A
+
R9
220R
R11
1.8k
R6
330k
Tr1
BC214C
Tr5
R22
BC214C
270R
R18
3.3k
+50V
4A
+
R11 is Limiter for
ESL57 Speakers
R15
100R
R35
0.08R
R26
75R
Page 1 of 1
-50V
F1
+
R7
3.3k
C5
100u
R14
560R
D1
LR120C
Input
C1
680n
R3
22k
2
IC1
R4
22k
R1
220k
3
-
R10
1k
8
6
+
C3
3.3p
C2
100u
3V
R12
3.3k
R17
3.3k
Tr2
ZTX304
C8
120p
R20 1k
C6
1n
R16
180R
R2
R21 1k
M12368 iss.9 PCBs used for serial
numbers from 9000 to 29000
R43
22R
T1
2N4992
D6
IS920
R27
8.2k
Tr9
BDY77
R38
47R
C13
10,000u
R40
2.7k
2W
T2
SC1418
Output
C12
100n
Dumpers-out
Tr6
Bc214C
R25
22R
C10
47u
D4
IS920
R37
22R
Tr8
40872
R30
560R
R31
560R
L1
6.8u
Note: This point is
connected to input
ground but ideally
should be connected
to other side of R2
C14
10,000u
C19
1n
R29
8.2k
Tr10
BDY77
R33
22R
C16
100n
F2
d.c. feedback
4.7k
[email protected]
Revision: 1
Page Size: A4
QUAD 405 - M12333 iss. 4
8 Feb 2003
Speaker
R39
10R
R36
0.08R
R28
75R
4A
R5
red
+
D2
LR120C
R42
15k
D5
IS920
L2
3u
+
R8
3.3k
D8
C17
10u
ClassA-out
10R
Input ground must
be connected to
chassis at DIN socket
to prevent oscillation
see - R39 C12
L3
6.8u
R41
22R
Tr7
40872
C11
330p
1
4
D3
IS920
Tr4
ZTX504
R23
1.2k
C7
330p
7
Tr3
ZTX504
R24
22R
R13
22k
C4
47n
LM301A
+
R9
220R
R11
1.8k
R6
330k
Tr1
BC214C
Tr5
R22
BC214C
270R
R18
3.3k
+
R11 is Limiter for
ESL57 Speakers
R15
100R
+50V
C15 4A
100n
R35
0.08R
R26
75R
Drawn:
K. Snook
Checked:
Page 1 of 1
-50V
F1
+
R7
3.3k
R11
1.8k
Input
C1
680n
R3
22k
2
IC1
R4
22k
R1
220k
3
6
+
C3
3.3p
C2
100u
3V
R12
3.3k
R17
3.3k
Tr2
ZTX304
C8
120p
R20 1k
C6
1n
R16
180R
R2
R21 1k
D2
LR150C
R43
22R
T1
2N4992
D6
IS920
R27
15k
Tr9
BDY77
R38
47R
C13
10,000u
R40
2.7k
2W
T2
SC1418
Output
C12
100n
Dumpers-out
Tr6
Bc214C
R25
22R
C10
47u
D4
IS920
R37
22R
Tr8
40872
R30
560R
L1
6.8u
Note: This point is
connected to input
ground but ideally
should be connected
to other side of R2
C14
10,000u
C19
1n
R29
15k
Tr10
BDY77
R33
22R
C16
100n
F2
4A
d.c. feedback
4.7k
[email protected]
Revision: 2
Page Size: A4
QUAD 405 - M12333 iss. 5
8 Feb 2003
Speaker
R39
10R
R36
0.091R
R28
75R
R31
560R
R5
red
+
R8
3.3k
M12368 iss. 9 &10 PCBs used for
serial numbers from 29000 to 59000
iss. 10 PCBs same as issue 9
except power transistor pads
modified for production.
R42
15k
D5
IS920
L2
3u
+
-15V
D8
C17
10u
ClassA-out
10R
Input ground must
be connected to
chassis at DIN socket
to prevent oscillation
see - R39 C12
L3
6.8u
R41
22R
Tr7
40872
C11
330p
1
4
D3
IS920
Tr4
ZTX504
R23
1.2k
R10
1k8
LM301A
Tr3
ZTX504
R24
22R
R13
22k
C7
330p
8
+
R9
220R
C4
47n
7
-
Tr1
BC214C
Tr5
R22
BC214C
270R
R18
3.3k
+
R11 is Limiter for
ESL57 Speakers
R15
100R
R14
560R
D1
LR150C
+15V
R6
330k
C5
100u
+50V
C15 4A
100n
R35
0.091R
R26
75R
Drawn:
K. Snook
Checked:
Page 1 of 1
-50V
F1
+50V
4A
+
R7
3.3k
C5
100u
R14
470R
D1
BZY88-C15
Input
C1
680n
R3
22k
C7
330p
C4
47n
2
IC1
R4
22k
3
7
8
6
TL071
+
R10
560R
R12
3.3k
Tr2
ZTX304
1
4
C3
3p3
R1
220k
D8
BZY88-C5V6
D9
BZY88-C8V2
+
C2
100u
3V
C6
1n
R16
180R
D8
Tr7
40872
R23
1.2k
R17
3.3k
C8
-
120p
R21 1k
T2
SC1418
R38
47R
Output
C12
100n
Dumpers-out
R36
0.091R
R28
75R
Tr6
BC214C
R25
22R
C10
47u
R30
560R
R31
560R
R5
Tr9
2SD424
D4
IS920
R37
15R
C14
10,000u
Tr10
2SD424
R29
15k
Speaker
R39
10R
L4
22u
Tr8
40872
D2
BZY88-C15
R40
2.7k
2W
R43
22R
D11
1N4003
C16
100n
F2
R33
22R
-50V
4A
d.c. feedback
4.7k
[email protected]
Revision: 2
Page Size: A4
QUAD 405 - M12333 iss. 6
12 March 2004
Drawn:
K. Snook
Checked:
Page 1 of 1
+
R8
3.3k
R42
15k
T1
2N4992
R27
15k
L2
3u
+
M12565 iss. 3 PCBs were used for
serial numbers 59001 to 62500
and 57301 to 57600
D10
1N4003
D6
IS920
ClassA-out
R20 1k
red
C13
10,000u
C17
10u
D5
IS920
C11
1n
Limiter
Grounded at
input DIN
socket
D3
IS920
+
R6
330k
R24
22R
Tr3
ZTX504
R13
22k
C15
100n
Tr5
BC214C
Tr4
ZTX504
Tr1
BC214C
R2
10R
R26
75R
R22
270R
R18
3.3k
R15
100R
R35
0.091R
FS1
3
2
R14
470R
R15
100R
R22
270R
R18
3.3k
C18
47u
3.3k
BCW60
D1
BZY88-C15
4
Tr1
BC214C
R13
22k
R2
10R
Tr3
ZTX504
1
5
R6
330k
Current Limit Network
C1
680n
R3
22k
C7
330p
C4
47n
R17
3.3k
R23
1.2k
1N4003
Q05 NIA
4
5
C11
1n
D5
IS920
Tr9
2SD424
2
R4
22k
3
R1
220k
+
7
V+
V4
R12
3.3k
R10
560R
IC1
Tr2
ZTX304
6
TL071
+
C2
100u
3V
D8
BZY88-C5V6
D9
BZY88-C8V2
Limiter
C6
1n
R16
180R
R43
22R
T1
2N4992
C8 120p
R20 1k
C13
10,000u
C17
10u
R42
15k
ClassA-out
-
red
R40
2.7k
2W
D10
3
N1
BCW61
10k
Tr7
40872
Tr4
ZTX504
2
D8
+
1.5k
39V
Input
C5
100u
C15
100n
+
R7
3.3k
68R
1
2.7k
+
1k
BCW61
+50V
4A
R35
0.18R
BCW60
L2
3u
Dumpers-out
R21 1k
T2
SC1418
R38
47R
Output
C12
100n
D6
IS920
Speaker
R39
10R
R36
0.18R
+
R37
15R
C19
47u
C10
47u
2
3
N2
1
R8
3.3k
D2
BZY88-C15
C14
10,000u
L4
22u
Q05 NIA
5
4
R30
560R
R31
560R
d.c. feedback
Tr8
40872
Tr10
2SD424
D11
1N4003
C16
100n
FS2
R33
22R
R5
4.7k
-50V
4A
[email protected]
Revision: 1
Page Size: A4
QUAD 405 - M12333 iss. 7
8 Feb 2003
Drawn:
K. Snook
Checked:
Page 1 of 1
+
+
M12565 iss. 5 PCBs (QUAD 405-2)
were used for serial numbers from
62501 to 66699
Grounded at
input DIN
socket
FS1
3
2
R14
470R
R18
3.3k
R15
100R
R22
270R
C18
47u
3.3k
BCW60
D1
BZY88-C15
4
Tr1
BC214C
R13
22k
R2
10R
Tr3
ZTX504
1
R6
330k
Current Limit Network
C1
680n
R3
22k
C7
330p
C4
47n
R17
3.3k
R23
1.2k
Q05 NIA
4
D13
1N4003
5
C11
1n
1N4003
D5
1N4003
2
R4
22k
3
+
R1
220k
7
V+
V4
R10
560R
IC1
R12
3.3k
Tr2
ZTX304
6
TL071
D8
D9
+
C2
100u
3V
C8 120p
BZY88-C8V2
Limiter
R44
R20 1k
C6
1n
R16
180R
L2
3u
R21 1k
T2
SC1418
R38
47R
75R
Dumpers-out
BZY88-C5V6
R43
22R
T1
2N4992
ClassA-out
-
C13
10,000u
C17
10u
R42
15k
Tr9
2SD424
red
R40
2.7k
2W
D10
3
N1
BCW61
5
Tr7
40872
Tr4
ZTX504
2
D8
+
1.5k
39V
10k
Input
C5
100u
C15
100n
+
R7
3.3k
68R
1
2.7k
+
1k
BCW61
+50V
4A
R35
0.18R
BCW60
Output
C12
100n
D6
1N4003
Speaker
R39
10R
R36
0.18R
+
2
C20
4n7
R37
15R
C19
47u
C10
47u
3
N2
1
R8
3.3k
D2
BZY88-C15
C14
10,000u
L4
22u
Q05 NIA
5
4
R30
560R
R31
560R
d.c. feedback
Tr8
40872
Tr10
2SD424
D11
1N4003
C16
100n
FS2
R33
22R
R5
4.7k
-50V
4A
[email protected]
Revision: 1
Page Size: A4
QUAD 405 - M12333 iss. 8
8 Feb 2003
Drawn:
K. Snook
Checked:
Page 1 of 1
+
+
M12565 iss. 6 PCBs (QUAD 405-2)
were used for serial numbers from
69700 to 72500
Grounded at
input DIN
socket
FS1
3
2
R35
0.18R
R7
3.3k
68R
BCW60
4
R15
100R
R22
270R
Tr1
BC214C
D1
BZY88-C15
R13
22k
R2
10R
1
5
C1
680n
2
R6
330k
R3
22k
Tr7
40872
C7
330p
C4
47n
R17
3.3k
R23
1.2k
Q05 NIA
4
D13
1N4003
5
C11
1n
1N4003
D5
1N4003
2
R4
22k
3
+
R1
220k
7
V+
V4
R10
560R
IC1
R12
3.3k
Tr2
ZTX304
6
TL071
D8
D9
C8 120p
BZY88-C8V2
+
C2
100u
3V
Limiter
C6
1n
R16
180R
R21 1k
Output
R39
10R
R37
15R
C14
10,000u
L4
22u
3
Tr8
40872
Q05 NIA
5
4
R30
560R
R31
560R
d.c. feedback
D11
1N4003
Tr10
17556
C16
100n
FS2
R33
22R
R5
4.7k
-50V
4A
[email protected]
Revision: 1
Page Size: A4
QUAD 405 - M12333 iss. 9
12 Feb 2003
Drawn:
K. Snook
Checked:
Page 1of 1
+
2
1
D2
BZY88-C15
Speaker
+
C19
47u
C10
47u
N2
R8
3.3k
C12
100n
D6
1N4003
R36
0.18R
+
C20
4n7
L2
3u
T2
SC1418
R38
47R
75R
Dumpers-out
M12565 iss. 7 PCBs (QUAD 405-2)
were used for serial numbers from
72501 to 82999 and 83000 to 84999
with voltage selector omitted
Grounded at
input DIN
socket
R44
R20 1k
BZY88-C5V6
R43
22R
T1
2N4992
ClassA-out
-
C13
10,000u
C17
10u
R42
15k
Tr9
17556
red
R40
2.7k
2W
D10
3
N1
BCW61
Current Limit Network
D8
C18
47u
Tr4
BC556B
+50V
4A
+
1.5k
39V
10k
Input
R14
470R
3.3k
1
2.7k
C5
100u
C15
100n
+
1k
BCW61
+
BCW60
FS1
3
2
R14
470R
3.3k
BCW60
4
R22
270R
R15
100R
Tr1
BC214C
D1
BZY88-C15
Tr3
BC556B
R13
22k
R2
10R
C18
47u
1
5
R6
330k
Current Limit Network
R3
22k
Tr7
40872
C7
330p
C4
47n
R17
3.3k
R23
1.2k
Q05 NIA
4
5
C11
1n
1N4003
D5
1N4003
D13
1N4003
2
R4
22k
3
+
R1
220k
7
V+
V4
R10
560R
IC1
R12
3.3k
Tr2
ZTX304
6
TL071
D8
D9
BZY88-C8V2
R44
R20 1k
L2
3u
C6
+
R16
180R
R21 1k
T2
SC1418
R38
47R
75R
Dumpers-out
1n
C2
100u
3V
C8 120p
BZY88-C5V6
Output
C12
100n
D6
1N4003
+
R37
15R
C19
47u
C10
47u
2
3
Tr8
40872
N2
1
R8
3.3k
D2
BZY88-C15
C14
10,000u
L4
22u
Q05 NIA
5
4
R30
560R
R31
560R
d.c. feedback
D11
1N4003
Tr10
17556
C16
100n
FS2
R33
22R
R5
4.7k
-50V
4A
Revision: 3
[email protected]
Page Size: A4
QUAD 405 - M12333 iss. 10
12 May 2004 Drawn:
K. Snook
Checked:
Page 1of 1
+
C20
4n7
R36
0.18R
+
Ground isolated
at phono
Speaker
R39
10R
Limiter
M12565 iss. 7 PCBs (QUAD 405-2)
used for serial numbers from 85000
onward - Note input earth change
with phono input connectors
R43
22R
T1
2N4992
ClassA-out
-
C13
10,000u
C17
10u
R42
15k
Tr9
17556
red
R40
2.7k
2W
D10
3
N1
BCW61
C1
680n
2
D8
+
1.5k
39V
10k
Input
C5
100u
C15
100n
+
R7
3.3k
68R
1
2.7k
+
1k
BCW61
+50V
4A
R35
0.18R
BCW60
F1
R7
2.7k
Tr1a(R14)
2SA1085E
Tr7
MJE15033
Tr3(Tr4)
ZTX753
R13
22k
D10
1N4006
D5
1N4006
ClassA-out
C4
680n 2%
R6
22k 1%
-
2
C1
680n 2%
Input
3
R4
3.3k
1%
R1
220k
+
C2b
1µ
C2
47u
3V
7
IC1
V+
V+
6
R12
2.7k 1%
Tr9
MJ15003
R38
47R 1%
R? 10R
Tr2
2SC2547E
TLE2071
C17
10u
R42
15k
D13
1N4006
C8
120p 1%
630V
+50V
C15
100n
C13
22,000u
63V
+
R2
10R
4A
R22
270R
Tr1b
2SA1085E
D1
BZY88-C15
CD1
1µ
R35
R15
220R-AOT
R43
22R
T1
2N4992
T2
SC1418
Output
4
Feedback?
C6
1n
R3
22k
1%
R16
180R 1%
R20
1k 2%
C12
100n
L2
3u
D6
1N4006
R21
1k 2%
Speaker
R39
10R
Dumpers-out
R36
D2
BZY88-C15
C10
47u
L4
22u
C14
22,000u
63V
Tr8
R30
560R
R31
560R
Tr10
C16
100n
F2
R33
22R
MJE15033
R5
D11
1N4006
MJ15003
4A
d.c. feedback
4.7k
[email protected]
Revision: 6
Page Size: A4
QUAD 405 - DCD Mod-3
Sept 2011
Drawn:
K. Snook
Checked:
Page 1 of 1
-50V
+
R8
2.7k
+
CD2
1µ
R37
15R
Components marked in grey with blue reference designators
should be removed to disable current limiting - This should be
done in conjunction with a change of Tr9 and Tr10 to higher power
devices like MJ15003
Tr3 should be bypassed base-emitter as shown and it
should then be possible to safely remove C19 fitted across
Tr10 collector-base on the solder side of the PCB - If you
are not sure bypass Tr3 and leave C19
Components marked in green are
changes or additions to the original
n.f. = not fitted and Link = remove
and wire across.
For original sensitivity 0.5V for 100W
fit R4 = 1.6k and C2 = 100uF
+
R7
2.7k
C5
n.f.
D1
BZV85-C15
CD1
1µ
As shown sensitivity is 1V for 100W
For sensitivity of 1.5V for 100W
fit R4 = 4.7k and C2 = 33uF
ESL 57 limit
not fitted
Input
R3
22k
2
R4
3.3k
+
R1
220k
-
R13
22k
8
IC1
3
R10
Link
+
C2
47u
3V
1
4
6
C11
Link
Wire to 0V
R12
2.7k
R38
47R
C8 120p
re-positioned on
rear of PCB
Tr2
2SC2547
C6
1n
C2b 1µ-3.3µ
fitted on
rear of PCB
R21 1k
R16
180R
R2
R27
15k
Output
C12
100n
Dumpers-out
Tr6
BC214C
D2
BZV85-C15
D4
IS920
R25
22R
C10
100
R30
560R
Tr8
40872
C19
n.f
R29
15k
L1
6.8u
R37
22R
C16
100n
Tr10
R33
22R
C19 can be removed if Tr3 is
bypassed but if you cannot check
for stabilty leave it in place
d.c. feedback
R39
10R
R36
0.091R
R28
75R
R31
560R
R5
10R
L2
3u
+
R8
2.7k
Tr9
D5
1N4003
D6 1N4003
R20 1k
10R
CD2
1µ
C15
100n
R23(R19)
n.f.
C3 n.f.
TL071 or
OPA134
OPA604
L3
6.8u
R41
22R
Tr7
40872
ClassA-out
R17
Link
+50V
4A
D3
IS920
R24
22R
Tr4
ZTX753
Tr3
n.f.
C7
n.f.
7
Tr5
R22
BC214C
220R
R18
n.f.
Tr1
2SA1085
C4
680n
R6
22k
C1
680n
R9
Link
R15
220R
R14
2SA1085
R35
0.091R
R26
75R
F1
F2
4A
4.7k
Note the 2 different ground symbols either side of R2 - probably to prevent internal hum loops The input ground connects to the chassis at the input DIN socket and originally the other side of
R2 connects to chassis via the bolt in the heatsink - Even if you do not provide a formal ground
wire to the 0V speaker terminal as I show you should ensure that both sides of R2 are at the
same potential - If one ground is missing the voltage at the speaker terminals will be about
20mV if both grounds are in place it should be less than 1mV - Both grounds should be
connected to chassis
[email protected]
Revision: 3
Page Size: A4
M12368 PCBs to DCD Mod-3
1 Sept 2008
Drawn:
K. Snook
Checked:
Page 1 of 1
-50V
Note: This is only a schematic - It has been
implimented as a mod to 12368 iss.10 and
12565 iss.7 PCBs but the cicuit can oscillate
at VHF radio frequencies which do not
appear at the output but can put the
transistors in compression - increasing
the distortion and dissipation
3
R4
3.3k
1%
R1
220k
3.3u
+
C2b
C2
47u
3V
D1
BZY88-C15
-
C4
680n 2%
7
V+
R3
22k
1%
4
6
TL071 or
TLE2071
OPA134
OPA604
LME49710
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
Tr4
ZTX753
Tr9
MJ11016
R104
R14
22k
R12
2.7k 1%
IC1
V+
R2
10R
Tr7
MJE15033
D13
1N4006
R38
47R 1%
Tr2
2SC2547E
47R
Feedback?
R16
180R 1%
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
Speaker
Output
L2
C12
100n
3u
R20
1k 2%
C8
C6
1n 2%
C13
22,000u
63V
120p 1%
-
Input
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
Tr1b
2SA1085E
+50V
4A
C15
1µ
R106
AOT
+
2
R22
270R
+
R6
22k 1%
F1
R15
220R
R7
2.7k
CD1
1u
lookout for updates and refer to my
website for further information
C1
680n 2%
Tr1a
2SA1085E
R39
10R
R21
1k 2%
D6
1N4006
C14
22,000u
63V
47R
+
R105
Tr10
MJ11015
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
CD2
1u
R8
2.7k
D2
BZY88-C15
R101
10k
Q45
ZTX653
Tr108
MJE15032
C16
1µ
R103
15R
R5
Net Audio QUAD 405 Mk3 Mk 3
Circuit diagram schematic
F2
-50V
4A
4.7k
Note: The “Current Dumpers” Tr9 and Tr10 are complimentary Darlington transistors —
This layout WILL NOT work with low hfe output devices due to the base current required
— The “Current Dumpers” can be made complimentary MOSFETs If D13 and D6 are
changed for resistors but care must be taken to ensure that the Source-gate voltage
can be obtained within the limits of Tr7 and Tr108 current drive
[email protected]
Revision: 3
Page Size: A4
QUAD 405 - DCD Mod-4
1 Apr 2005
Drawn:
K. Snook
Checked:
Page 1 of 1