Cornish TB-83

[spoontex]

Hi,

I'm planning to build this pedal. But I have some questions. Can I use BC183C instead a BC549? And what is the best way to add a volume pot? Changing R11 for a 10k pot?

Thanks.

[PRR]

Yes.

[antonis]

I'd suggest to make R10 a 100k pot while ensuring succeding effect input impedance about 1M or so..

By making R10 10k you result into 4k effective Collector resistor (6k8//10k) hence lowering Q1 stage gain..
(from over 100 down to about 65..)

edit: Just realized you're talking about R11 and not R10.. Proceed as Paul said..

[PRR]

> talking about R11 and not R10..

Then maybe I am mixed-up also.

PLEASE get a crayon and MARK-UP a plan. This reduces ambiguity and reader mental-fog.

[spoontex]

And wich method is better?

I assume if you change R11 with a pot, they change the bias of transistor no?

[Radical CJ]

https://images.app.goo.gl/dpZvQMHbYFKD8bgY9

The Guild 1990s Brian May Booster is basically one of these with a buffer up front and 250k volume pot on the back.

I made myself one of those about 10 days ago, and its the best silicon treble booster I've ever tried (although I really haven't tried that many). That link should take you to a schematic.

I used BC239Cs, with hfe around 550 (from memory), and that sounded better than 2N3904s with hfe of around 350.