krankosaurus/ ZVEX BOR question

[mordechai]

In the Krankosaurus schematic....coming off of the first BS170 is a 470K resistor in parallel with a 470pF cap.  What does this combination do, as opposed to what would happen if the signal was just run through a small-ish value cap or a resistor and small cap in series?

[Jaicen_solo]

They act as a high-pass filter to accentuate high frequencies/roll of bass. It keeps the clipping from getting muddy by effectively adding more gain to the high frequencies.
Well, less attenuation to high frequencies, however you cut it the effect is the same.

[mordechai]

If one ups the value of these components in equal proportion (so, changing the 470K/470pF to 560K/560pF), would this consequently increase the amount of brightness, i.e., attenuate less of it?  Or would lowering the component values do that?  Would changing one component but not the other result in a wider or more narrow spectrum of frequencies affected?

[Jaicen_solo]

I'm sure theres a calculation for It but im not sure to be honest.
If you raise the value of the cap, usually that lowers the cutoff frequency, however I'm not sure what would happen if you also raise the value of the resistor. Why not try it and fine out!

[mordechai]

I did!  I couldn't tell too much from changing the resistor value, but I increased the cap value and there was more high end.  I actually rather liked it...just a subtle bit of difference, but enough to give the tone a touch more "chime".