PCB for microcontroller VCO + vactrol VCF module (v1.5 - 6HP)
Hear it here: https://soundcloud.com/yorkmodular/badtrip-vcovcf-sample
VCO + Vactrol LPF = Bad Trip ... ... which is pretty much what it is.
Combines a switchable square/saw VCO with a vactrol-based resonant low-pass filter for generalised acidic wonkiness. As well as the usual front-panel controls, there are a bunch of trimpots on the back-side of the board to allow you to alter the response of the filter vactrols - depending on the settings you choose, hilarity may well ensue.
⚠️ IMPORTANT NOTE ⚠️ - since the VCO part of the module is microcontroller-based there are limits on the range of CVs that can be handled. Basically, a negative CV will be 'rejected' (ie. treated as 0V) and anything over 5V will be clipped to 5V, thus limiting the range to 5 octaves - there are ways around this, but they're pretty hacky.
If you're having problems with range (or lack of it) then make sure that the CV pot is turned fully clockwise _and_ that your CVs fall within the appropriate range. The firmware for the VCO can be found at https://bitbucket.org/yorkmodular/badtrip-vco/src/master/ - it is available under a permissive license so feel free to hack on it. You'll also find BOM and design files for panels.
This is version 1.5 of the board - it adds a fine-tune capability via a surface-mount pot (Bourns 3314G or equivalent) on the rear of the board. This particular component is easy to hand-solder.