"Frankenstein'ed" circuit has ground problem(s). Please help, if you can

[Kipper4]

here in the rog schematic.

http://runoffgroove.com/ubescreamer.html

[KarenColumbo]

V1.2

[KarenColumbo]

here in the rog schematic.

http://runoffgroove.com/ubescreamer.html

Ah. sorry! Yeah, I omitted this stage completely You suggested several times to put the EQ stage before the drive stage, so I did - and it's much more efficient this way. I only took U1B, U1C and U1E of the ROG schematic.

[Kipper4]

Yer I missed that. Gottya now.

[KarenColumbo]

Here's V1.3. I put in a BMP-like passive EQ instead of the mid boost (thanks, Kip!), cranked up IC1B with an 270k resistor (should be >11 then), got rid of the "Bass Boost" switch (which killed all character of any guitar when activated) and settled with a 2n2 cap (C14). Any other value did seem to make things worse, omitting it, too.



This thing is excessively complicated, of course. But I think it sounds quite nice for a multi-stolen-circuit-bastard

I also experimented with different diode/LED combinations: orange, red, green, blue, pink, UV, Schottky, Zener - and stuck with the original 914s.

[samhay]

Some thoughts regarding V1.3:
Your blend might work better if your two signals were not 180-ish degrees out of phase with each other.
You don't need Q3.
IC1B has quite low input impedance, so will load down your town stack.

[KarenColumbo]

Some thoughts regarding V1.3:
Your blend might work better if your two signals were not 180-ish degrees out of phase with each other.
You don't need Q3.
IC1B has quite low input impedance, so will load down your town stack.

Thanks, Sam!
I assume, I could configure IC1B as a non-inverting amp to get rid of the phase issue.
How would you eliminate Q3? Just omit it?
I'll have a read regarding impedance - I put IC1B in to avoid impedance issues - but I think I messed up :/

[samhay]

Yes - make IC1B non-inverting with a large-ish bias resistor. It can still be configured to have gain if you need it.
IC1A can easily drive the tone stack, so yes, just omit it.

[KarenColumbo]

Am I on the right track with this little snippet?

I know, this must be extremely basic - but that's something to get a hold on to

[samhay]

Yes-ish.
You want to connect R1 and Rcomp to half supply. Actually, you don't need Rcomp here and can jumper this.
Instead of connecting R1 to Vb, you can alternatively add a series capacitor and then connect to ground (or Vb or V+).

[KarenColumbo]

Gentlemen, thank you very much for your invaluable input! I feel, it's time to break this project down into the respective building blocks and have a long good read about issues like biasing, virtual ground, impedance and general opamp structures.