Hey, it's another Tone Bender Mark II Pro question!!

[Chris Goodson]

I'm building the positive ground pnp version and I noticed GGG has R3 listed as 47k, but Fuzz Central says it's 100k.  :?   Well, which one is it?

[petemoore]

Options include trimpot [100k] or, 50k+47k trimpot.
 Or, 100k with a little extra leg above the board, then tag a 100k on there to see what around 47k sounds like.
 This IIRC is the collector resistor for Q1, [or Q2], I can't see the schematic, and will alter the bias condition, which, is probably either not critical in that either will probably work, and/or because transistor gain/leakage also alters bias voltages.

[phillip]

The original value was 100K.  The 47K is a modified value that will help to tighten up the sound and increase sustain a bit.

Phillip

[Chris Goodson]

Ok, so it's 100k, I just wanted to know that I built the original circuit .  It surprises me that the exact value wouldn't matter on that one.  I'd think that the collector resistors would make all the difference in the sound.  As far as tweaking the circuit goes, if the original helped Jimmy Page get the sounds he got then thats good enough for me.
Although, one thing I'd like to change about it is the tremendous amount of treble it has.  I can get a nice sound out of it if I set my amp to the right settings, but thats sort of a pain in the ass to have to do that whenever I want to kick it on.

[Chris Goodson]

:shock:

[phillip]

Do you have the 0.01uF capacitor to ground before the input capacitor?  That helps to remove some of the highs from the circuit.  You could also try increasing the value of the output capacitor.  0.047uF or 0.1uF would pass more bass and block more treble.

Phillip

[bluesdevil]

Do you have the 0.01uF capacitor to ground before the input capacitor?  That helps to remove some of the highs from the circuit.  You could also try increasing the value of the output capacitor.  0.047uF or 0.1uF would pass more bass and block more treble.

Phillip

I know doing those things really got mine sounding exactly as I wanted it..... really opened it up letting the extra bass out, what a difference!!!!  If it's still too sharp after all that, try putting a .001uf cap across the outer lugs of the volume pot along with those changes.