Build Report: Dead End FX Q2 - Frostwave Resonator Clone

[box_maker_1]

Just a quick build report on the Dead End FX Q2.  This pedal is a clone of the Frostwave Resonator, which is itself a clone of the Korg MS-20 Synthesizer filter section (Highpass and Lowpass filters).

tl;dr - This pedal sounds great. Super gritty filter that saturates nicely. It's the opposite of a smooth Moog-style filter, if you are an analog synth filter kinda person

Cheers to Dino for being so responsive and answering my questions about the build. This was my first DEFX project, and it was awesome to have access to the man himself!
I followed the advice of this post: https://www.diystompboxes.com/smfforum/index.php?topic=126992.msg1217642#msg1217642
2.2N for C23
20K Trimmer in place of the 100K Trimmer
2K Ohm for R11
For the clipping LEDs, I used the smallish red ones, and they sounds plenty gritty (in a good way)

Upon initial build, the resonance on both filters was acting really weird, the pot was backwards, the filter wasn't self-oscillating properly and distorting in a bad way.  I tracked this down to bad CA3080AE chips from UT-Source in China.  I've had good luck with those guys in the past, but the CA3080s were definitely bad this time around. Dino pointed out that Small Bear sells them too. And indeed, the Small Bear sourced CA3080's rock.

This filter pedal has voltage control inputs for the filter cutoff and resonance. It sounds so good with an envelope follower controlling the cutoff. Check the sounds sample below. The first part is just me manually playing with the filter cutoffs, the second part has the Lowpass filter being controllered by an envelope follower.  Sweet sounding.

And I'm able to do my favorite highpass filter trick with the resonant highpass filter.  Crank the resonance up and keep the cutoff frequency low.  Makes for some thumpy bass.

Sound sample: https://www.aronnelson.com/DIYFiles/up/Q2_sample.mp3