Something here sounds too harsh

[Transistor-Transistor]

Hello all! I've been working on designing this BJT drive circuit for a few weeks now and I think I'm finally close to getting a winner.
However...
Once you get past around the 12th fret of the G string it gets really harsh sounding. Now I like a good cutting lead tone but this almost sounds like a lofi octave is warbling quietly when the note is picked.

Here's the schematic, diodes are 1n4001



I tried to add a Cap to ground after R8 but it didn't round out the harshness and made everything else too dark, I'm not even sure where I should tweak to mellow it out.

Also, this is probably worthy of another topic but the 1k gain pot is scratchy. I think some DC is getting in there and I'm not super sure how to block it.

Thanks in advance for your help!

[ElectricDruid]

Also, this is probably worthy of another topic but the 1k gain pot is scratchy. I think some DC is getting in there and I'm not super sure how to block it.

If the transistor is biased, there's the base bias voltage (minus the B-E diode drop) from the Emitter on down, so half of that is across that 1K pot.

The 9V comes in from R10+R8 to the collector. Then there's a DC path through R6+R9 to the base. You tell me what the base voltage is (if you've got it in front of you, you can measure it!), but it's not nothing. So yes, there's DC on the pot.

[Transistor-Transistor]

Oh man yep definitely DC there haha. Is there a way to block it for the gain pot or does the pot have to be moved somewhere else?

[GibsonGM]

Can you get rid of R7?  Then the cap would block DC. If you want fixed 1k, add it after (series) the cap, rather than in parallel...

[Transistor-Transistor]

I can't get rid of R7 because then the emitter won't be grounded. I suppose I worded it wrong. I really need a way for the pot to somehow not be scratchy with DC on it

[GibsonGM]

Aiee, my bad, LOL!  OK; how about the traditional fixed emitter R, and a 'gain cap' above it which goes to the pot, then ground ("limited bypass")?  Or gain cap off the pot wiper (see fuzz face).  You'd have to work out the values, of course.

[Transistor-Transistor]

Ooo okay I'll try that. Thanks!

[Transistor-Transistor]

Fuzz face gain control worked great! It also fixed the harshness so I guess it was like that because of the DC. Guess that just goes to show you how bad that is for your signal 

[GibsonGM]

The 'gurus' might know more about it, the 'why'...but there could be something to that. Maybe it was making an intermittent, or causing a DC current flow thru there that contributed? Strange things can happen! 

When in doubt, plagia...I mean, BORROW from circuits known to work, ha ha!

[Elijah-Baley]

Well... did you have some demo about it?

[duck_arse]

you can delete R17.