1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
D
D
C
C
B
B
A
A
1
VOX Amplification ltd.
1 Harrison Close
Knowlhill
Milton Keynes
Bucks, MK5 8PA
4
X-16709 AC30S1 Preamp
VD-A30031
ISS4-1
15-Aug-18
Title
Drawing Number:
Date:
Revision:
Sheet
of
Designed By:
Checked By:
P Scarffe
Dave Clarke
Issue
Change
Date
Signed
CHANGE HISTORY
BPJ-BBB-MONO
J1
VR1
A500K
R40
0R
R37
1M
C26
22pF 50V
R36
10K
R24
FB
GND
R54
1.5K
R50
C52
470pF 500V
C55
GAIN
CHASSIS_IN
C24
100nF 50V
R57
2.2K
R53
2.2M
C54
120pF 500V
R56
1K5
A1M
Treble
VR3
Bass
VR2
A1M
R86
100K
R72
10K
C80
56pF 500V
C108
47pF 500V
R62
R105
100K
R109
100K
R104
1M
R106
47K
R107
1K2
R108
1M
2
7
V1
12AX7
C72
22nF 400V
C99
100nF 400V
C109
100nF 400V
C107
100nF 400V
Master Volume
VR5
A500K
B+3
C38
100nF 50V
R100
C92
22nF 400V
R101
10K
R102
220K
R63
10K
R55
10K
GND
GND
C20
10uF 350V
C67
10uF 350V
C45
C95
R99
10K
C94
10uF 350V
GND
2
7
V2
Tube 12AX7
D1
1N5931B
D2
1N5931B
D8
NF
1
2
3
P22
Header 3 - Wide
GND
TO POWER AMP P10
HDC+
HDC-
HDC-
HDC+
P9
Header 3 - Wide
Send to Reverb PCB P3
SCREENED WIRE
SCREENED WIRE
R90
LINK
R89
NF
GND
Use Pin 2 to screen 1 and 3
Use Pin 2 to screen 1 and 3
G
D
S
Q4
LND150N3-G
G
D
S
Q3
LND150N3-G
Text
R117
22K
R118
10K
GND
18V, 1W
18V, 1W
R11
10K
R30
10K
C36
22nF 400V
3
4
4-1
29/05/18
11/07/18
23/07/18
PS
PS
PS
Remove D8 and D11
Change R98 from 2.2Meg to 100K
Add C36
