220p500p

.0047µF

630v

.002

2µF

6

30v

.0015

to VOL pot

to board

Vox AC-15 Modifications

More BrillianceReplace the Brilliance switch with this 2 pole 6 position switch for more tone options.

The extreme positions of this switch still maintain the original tone options.

STBY

250Ω

Double Pole/3 Position SwitchOff – Both poles are open

Center – Top pole is closedOn – Both poles are closed

B+

Standby Plus! This 3 position Standby switch allows you to choose between full B+ and a

lower B+.

Delta Tremolo/VibratoReplace the original internal Depth preset and 3

position Speed switch with a front panel DEPTH pot (1M-A pot with push/pull switch) and a Speed pot for

more control of the Trem/Vib effects. The switch is used to add another capacitor in parallel with one of the

oscillator caps to lower the LFO frequency. The .022µF results in a very slow speed for some nice swampy

Mississippi delta sounds.

You can also replace R55 with a yellow or red 5 mm LED rated for 1.7v to 2.2v and about 20mA to use as a front panel blinky indicator. This is just pure eye candy

and has no audible effect on the tremolo or vibrato.

220pF

500pF

.0015µF

.0022µF

.0047µF

6

5

4

3

2

1

C

CW

CCW

2 Pole 6 Position MBB

6

5

3

2

1

CW

CCW

4

C

NOTE! All terminals for half the switch are jumpered together and just used as a tie point for the caps.

T

SG

T

SG

2

3

1

5

6

4

Jump

NOR VIB

Separate

DP

DT

Jump! This mod allows you to easily jump the channels.

to VIB preampto NOR preamp

T

SG

IN

Channel Select Switch

to VIB preamp

13 2

6 4

to NOR preamp

5

The switch is a C&K 7211 ON-ON-ON. It is not a standard DPDT switch.Center position selects both channels.

(Alternate to Jump mod)

Channel Select Modifications

A

Top Cut250K-A

PA Gnd

B

.01µ

F 6

30v

.01µ

F 6

30v

+ +

50µ

F 1

00V

130Ω

10

wa

tt

OT

.0047µF

PPIMVDual

250K-A

1. Remove two 220K grid resistors and their jumpers.2. Relocate .0047µF cap to pots.3. Connect PPIMV ground to PA Gnd.4. Use shielded cable if wires are long (not necessary

for my layout).

Vox AC-15 PPIMV Modification