applying an high-pass on one channel

[garfo]

Taking in mind this circuit, how would I apply a high pass filter on lets say channel one of this circuit?

http://www.generalguitargadgets.com/pdf/ggg_mixer_lo.pdf

The idea is to mix two channels, but I want to filter the lows from channel one.

[RobA]

Are you looking for something like a rumble filter?

How you do it depends on how much rolloff you need etc. If you can get what you want out of a first order filter it can be pretty simple since C1 and R5 are already setting up a first order HP filter. You would just need to reduce the cap size for  C1 where the formula is f = 1/(2 π R5 C1).

If that isn't good enough, then you'll need to put an active circuit in before R5 and that'll probably need to be buffered.

[garfo]

Was thinking ofdoing it simle.Maybe, I'll try to reduce the input cap