Big Muff Pi Triangle Mod too bassy...

[studiostud]

Hey guys,

So I built a big muff pi triangle circuit off the tonepad layout.  The pedal works and the distortion sounds nice.  The problem is that it is really bassy.  I basically have to turn the tone pot all the way up to get it to a usable sound.  I understood that the triangle mod was intended to make the pedal less bassy but when I compare to my stock russian big muff, there is a huge difference in how much more bass the triangle has.  Can anyone give me a heads up on what components to look at to change?  is it components that need to be changed or could that be the result of a solder bridge somewhere?

[scondon]

There are problems with the Tonepad Big Muff Triangle layout.

what to fix:
A) Q2 will not bias correctly without R8 - try around an 8k2 in there. 
B) R1 should not be 3k3 but 33k or 39k
C) C2 should be 560p

for more discussion see here:
http://www.diystompboxes.com/smfforum/index.php?topic=69930.msg561550#msg561550

[Drake120]

BTW, is it just me being blind or the Big Muff project disappeared from Tonepad?

[The French connection]

BTW, is it just me being blind or the Big Muff project disappeared from Tonepad?

No, i think you're right! I can't see it too. 

[studiostud]

I tried those mods.  When I put in the R8, it basically started burping when I would hard strum.  Nothing consistent.  The 560pF didn't really change the sound as far as I could tell.  Swapping the R1 to 39K seemed to help a little bit, but it's still too much in the low end unless I crank the tone almost all the way up.  Any other suggestions to try?

[manson]

I'm not sure if the Triangle version has 0.1uf caps, but you can use these everywhere to reduce bass response. Except the caps in series with the diodes. Those are usually 0.047uf or 0.1uf. Increasing those to 1.0uf should give you less bass, because more low frequencies are being clipped.

[studiostud]

I'm not sure if the Triangle version has 0.1uf caps, but you can use these everywhere to reduce bass response. Except the caps in series with the diodes. Those are usually 0.047uf or 0.1uf. Increasing those to 1.0uf should give you less bass, because more low frequencies are being clipped.

The triangle does use 0.1uF caps and the caps in series with the diodes are 0.05.  I'll try swapping those with 1.0uF.  What about other resistor values?

[studiostud]

**UPDATE**  so I ended up swapping out the .05 uF caps in series with the clipping diodes with 0.15 and that seems to be a lot better.  there is much more tonal range now.  It's still similar to my old stock russian black one but I think the sound is richer and more usable.  Thanks for the help!