Manifold Research Centre Yodo

yodo is a distortion and VCA based on the sunn((O))) beta-lead preamp, where the distortion stage is based on CMOS hex inverters 

(CD four-zero-six-nine).

It has a colour section to shape bass, mid and treble.  

there’s a VCA on the output, plus an extra CV controllable feedback path with a send/return section.

BEWARE: yodo is a self-conscious machine and can speak on its own.

This is an eurorack adaptation of the sunn((o beta lead amplifier circuit, I used to play a rhodes through this amp, and i really liked the tone. Many guitar amps are quite limited in the frequency spectrum, because they’re thought for guitars, this one is not, at least to me, i loved it and I thought, why don’t you make it for eurorack? And so I did, this thanks to fender ( who bought sunn((o in the 60/70ies) that released all the service manuals on their website, go and have a look because its a goldmine. The amp runs on +-15v and uses CMOS hex inverters in the distortion section. Apparently hex inverters where used a lot in audio circuits because the had a very similar “structure” as opamps, but that’s all I know, there are various distortion circuits which uses them though.