Output buffers and wahs - effects on range and 'q'

[brett]

Hi
a long time ago I put an output buffer in my wah, figuring it was a good thing to do.
Ever since, the tone of the wah has bugged me.  It seems too "peaky" and the treble is very prominent.

Looking at a wah schematic (such as this one from FP at Tonepad: http://www.tonepad.com/getFile.asp?id=114), it seems that if you have a typical stompbox next in the chain (with, say an input impedance of 100k), that when lug 2 and 1 are opposite, the impedance to ground is 1/(1/100k + 1/100k) = 50k.  If a high impedance (1M) output buffer is used, the impedance is 1/(1/100k + 1/1M) = 99k.  That's a big difference. 

How does this affect the range (and possibly the 'q') of a wah? I seem to have forgotten most of what I once knew about wahs?
thanks for any advice

PS or maybe I should just make the buffer resistance 100k and forget the theory?

[Paul Perry (Frostwave)]

Before the output buffer was put on, the wah was looking at a certain amount of capacitance in your cable (maybe 200pF, or something of that order).
So if you put 200pF from the wah section output to ground, maybe the high end will go away.
In fact, this is one of the very few places you could put an old air cored tuning condender from a radio into a stompbox!! some o those were 15pf to 450 though most were 20 to 200pF.

[brett]

thanks Paul
I'll experiment with it at the weekend and report back.