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Adding a mid and distortion knob to an existing preamp circuit

Started by slimjohnny, September 28, 2019, 08:16:44 AM

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slimjohnny

I found this preamp circuit for a 30W solid state amp I want to build. The only problem is that it only has a 2 band tone control(bass and treble) and I would like to make it a 3 band tone control, the other problem is that it only has one gain knob,( they call it gain in the website but I'm not sure of they mean overdrive or just volume). Anyways I would like to have a volume and a distortion knob.

Here's the link to the circuit: http://www.zen22142.zen.co.uk/Circuits/Music/guitar_tc.htm



How would I make these changes?

alessandro_gfdp

#1
insert in series with R2  a 500k pot and wire in parallel a couple red leds,move VR1 on the output.
Mid pot is not really necessary,those are boost and cut bass and treble pots,so if you want to scoop the mids just raise them above 5,mid boost under 5.

slimjohnny

Thanks for the quick reply, how exactly would you move VR1 to the output?
And, although it may be unnecessary, how would you add the mid pot(i'm still unsure if I add it or not)

Edit: I just now noticed that this tone control system works differently than the marshall or fender ones, so never mind the mid pot

phatt

This is a bit silly R1 at 10 meg is just insane for Elguitar,, only useful for a passive piezo PU.  I meg is miles high enough. Even try 470k.

Also add some series resistance between C1 and input,,unless you want to pick up radio stations. try at least 1k~10k
I doubt you will get useful distortion out of this circuit if that is what you hope. :-X

Personally there are far better circuit designs some likely floating around on this very forum,, too busy ATMo but others here might help out.
Phil.