Simple adjustable highpass?

[earthtonesaudio]

I'm looking for a simple adjustable highpass for the input of my CMOS inverter based distortion.  I also want to use a 10k pot if at all possible. 

Anyone have any good possibilities?  I'm thinking something along the lines of the input of the Easy Face. (blend between 2 caps).  I'm at a bit of a loss as to the theory behind those parallel R-C filters.  The books I've read skip over this type of filter, and the Wikipedia only has info for this filter going to ground, not in series with the signal. 

Can someone point me in the right direction?

Thanks!

[John Lyons]

Check out these:
Joe Gagan's Easy Face (with adustable cap blend) GGG. This blends a big and a small cap with a pot.

Mark Hammer's Stupidly Wonderful Tone Control. Usually used on the output but no reason is can't be used on the input.
There are a few variations including a HPF at AMZ in the lab notebook section.

Gus also posted one called the" plus", I think (Dist+) You can search for that here. Depends on the circuit though...

John

[earthtonesaudio]

Thanks John, I'd heard of the Easy Face but never actually seen the schem.   That helps.

This is the input gain stage of my circuit.  I would really like to just blend between a 1n cap and a 4.7n cap at the input.  The range of tones between those two is just right for my circuit.  But I want to keep that 100k input resistor fixed, and I have a lot of 10k pots I want to use for controls.  On the Easy Face, the 100k Blend control doesn't have any resistance after it, so I was concerned about that difference. 

Another question: Does the Easy Face blend control work well with small capacitance/resistance values, or does it have to be large to work right?


My circuit: