YAMS VCF (BStock)

MS20 Filter

Why are these B-grade? Basically, I goofed (twice) when laying the board out - the cutoff pot response is reversed and I forgot to connect the switch on the CV jack up to the 12V supply, meaning that it's now connected via a 10k resistor. It's ugly, but it works. These goofs have been corrected in the new board run.

My take on the MS20 voltage-controlled filter - if you want squally, resonant acid sounds then this may well be right up your alley.

Built around an LM13700 transconductance amplifier, this filter uses a pair of red LEDs in the feedback path to make things a little more ... interesting, but other than that it's a straight-up lifting of the classic MS20 design.

Subtle it isn't, but hey it's an interesting sounding filter nonetheless.

Has both low-pass and high-pass inputs, which should be pretty self-explanatory and there's nothing at all to stop you using them both together (hilarity often ensues here, since you'll get a really screwed-up bandpass-style response).

As supplied, the switch connection on the cutoff CV input is connected to +12V via a 10k resistor; this means that you'll get some control over the cutoff frequency even if there's nothing plugged into the cutoff jack. Resonance is also controlled via a pot but there is no voltage-control option (this may change in future, though)

4HP wide - supplied with power cable and mounting hardware.