Re: Adding bass control

Posted by induction on May 10, 2016; 6:49pm
URL: http://guitar-fx-layouts.238.s1.nabble.com/Adding-bass-control-tp30475p30483.html

The Fat Control is a simple boost (about 3dB) followed by an active EQ (low Q bandpass centered around ~350 Hz). The output pot pans between the simple boost output (bypassing the EQ) and the EQ stage output. It gives a flat response with a 3dB boost when the mid control is set to 0.

For flat response: you can easily add a switch to set the control to 0, or you could just step on the bypass switch, which seems like it would be easier.

For bass cut: Switching the input cap would work fine. With the mid pot at 0, a 1n input cap gives you a high pass filter with corner frequency near 150 Hz. A 470p gives you an fc near 300 Hz. At 220p, fc is near 700 Hz. As you turn up the mid pot, you get a wide bandpass filter centered around 450 Hz, 650 Hz, and 1kHz, respectively.

I'm curious why you want to cut lows from your low-mid boost. Understanding how you want it to sound and how you want to use it may suggest other options. For example, yes, you can change the output caps. (There are two of them, one for the flat boost side and one for the EQ side). If you want the bass cut to depend on the mid pot setting, you can change one or both of those caps or put them on a switch. You could also adjust the components in the EQ stage to alter the response.

Lots of options, depending on what you want to do with it.