Good Highpass filter cutoff?

[ReeceAblaze]

Hello I am building a boost pedal and I want it to have an optional HPF. What frequency cutoff is goof to boost those screaming highs?

[GibsonGM]

Many people look at existing designs and try out a 'circuit snippet' and see if it suits what they're after, Reece.   If not, you can always change some component values to take out more bass, or add it back in.   

Without something to look at (your boost), it's hard to recommend what direction you should go in.   The overall circuit topology is likely to play a large role in determining what component values you'll use, as will where the filter stuff is located (input? output? in a feedback loop?)     Do you have something in mind you're working with?    Boost w/ "HPF" could be as simple as changing an input cap via switch, for example.

[Mark Hammer]

It's not immediately clear what role you want the HPF and boost pedal to accomplish.  For instance, do you want accentuation of highs?  Do you simply want attenuation or outright elimination of lows, but things relatively flat above that?

A simpler shallow-slope single-pole filter with a higher corner frequency (e.g., starting around 1khz) would be appropriate for "paying more attention to" the highs, while still permitting mids and lows to pass.  A strategy like what the Rat uses - separate gain-setting for the upper and lower parts of the spectrum - would also be useful.  In fact, replace the 150k gain pot on a Rat with a 4k7 fixed resistor, omit the clipping diodes, and you'd have a reasonably decent treble booster. 

On the other hand, if the goal is to tighten up some drive pedal after the booster, then you might want a 2-pole HPF, variable with a dual-ganged pot, or perhaps a 3-position toggle or rotary switch to select rolloff point.

[garcho]

post your schematic