Highpass pedal- bump in the lows?

[Eddododo]

I whipped up a little highpass filter. works pretty great, but it seems to have a little BOOST of the lows of my bass when engaged with the frequency at its lowest.
Is this probably just because of the inherent gain of the design in the second stage, and it just 'seems' like a low boost when its really just a boost?
I'm 'pretty sure' i have a pretty-much butterworthish design, but that statement in itself alludes to my not knowing.. so it could be a lumpybump around the cutoff?

fyi there are two switched-in capacitors also of .022u value in parallel with the existing filter caps. the LOWEST possible cutoff freq is about 30hz, and the highest was something like 700

again it works quite well, just curious about the boost and wondering if i should have used a volume on the end after all..



Could i take the output from the junction of the 6.8k and 10k resistors in the second amp's feedback.. thing. its feedback thing
that would give me a unity gain output, correct? understanding that this would limit the expected headroom it a deceptive way?

[Keppy]

I put those numbers into a filter calculator and didn't get any resonant peak.

Is this probably just because of the inherent gain of the design in the second stage, and it just 'seems' like a low boost when its really just a boost?

That's what I'm thinking, based on reading and not hearing.

Could i take the output from the junction of the 6.8k and 10k resistors in the second amp's feedback.. thing. its feedback thing
that would give me a unity gain output, correct? understanding that this would limit the expected headroom it a deceptive way?

I don't see any problem with that (see link below). You could even replace the 6.8k with a pot to control the boost.

I'm 'pretty sure' i have a pretty-much butterworthish design, but that statement in itself alludes to my not knowing.. so it could be a lumpybump around the cutoff?

What you have appears to be a sub-Bessel. See here for Butterworth values: http://sound.westhost.com/articles/active-filters.htm#s3

Almost everything I know about filters is from that link.

[PRR]

A near-Buttery filter (lo- or hi-pass), the corner seems to "stand out" because you expect to hear something beyond, but don't.