Repeater tone control?

[kaycee]

As regards the Vox Repeat Percussion Tremolo. When I build them I usually put the input capacitor on a switch, the original value cuts a lot of volume and gives a thin tone, but is essential for 'that' sound. I usually have 10nf and 100nf on the switch, but a guy I built one for recently would like to have more adjustment over the tone.

My first thought for achieving that would be to use a 100kB pot to fade between the two values. I'd be interested in any comments on that idea, or further suggestions on how to do it, thanks

[thermionix]

I did that with my Ge Fuzz Face and it works great.  I just copied it from something else I'd seen, the input going directly to the smaller cap, and at that point 100KL pot (variable resistor) to the other cap.  Then the two caps connected at the other side, into the rest of the circuit.

Like this, but ignore the pre-gain:

[Kipper4]

You'll probably want to experiment with the cap values and pot value too before commiting to a pcb.
Trial with different pick ups and amps.

I really liked it in a hybrid fuzz.

[kaycee]

Thanks, that pretty much what I was thinking, might have to go above and below the switch values to get the same range of tone. One thing though, why tie in one of the lugs of the pot? I was going to run input to two, put a cap on each outer, join the other legs and run to circuit input.

[Kipper4]

Try it and see. Worst case you have to rewire the pot.

[GibsonGM]

Thanks, that pretty much what I was thinking, might have to go above and below the switch values to get the same range of tone. One thing though, why tie in one of the lugs of the pot? I was going to run input to two, put a cap on each outer, join the other legs and run to circuit input.

The "tie in" means that C1 is always in circuit, and you are blending in C7 with it. The resistance between the 2 sets the degree of blend.

If you don't have C1 tied, you will move away from C1's value toward C7...see the difference?

[kaycee]

Thanks for the help Gents. I used the tied method running a 4n7 on the tied side and a 100n on the other leg. The user is pleased with it so thanks.