Even VCO Hard Sync


I am trying to use the H.SYNC input of the Even VCO oscillator. Unfortunately, I do not get it to work. Should I expect the same behaviour as the VCV VCO, or am I missing something?


Yes, it was never implemented. It doesn’t do anything. Our EV-3 is derived from EvenVCO, but has three VCOs and sync between them, although the sync sources are limited to other EV-3 VCOs. Here’s a link to the manual: https://github.com/squinkylabs/SquinkyVCV/blob/main/docs/ev3.md

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I’m a little surprised this has never been ‘fixed’

Is it particularly hard to implement?

Here’s where I show my ignorance once more: isn’t syncing just a reset for a vco? That’s been my assumption trying to work with it.

Yes that’s correct. But the feature has always been called “sync” and never “reset”. But why do you say “just”?

I can’t speak for the author of EvenVCO, but I can say it was very difficult for me to implement. It is very easy to do a naïve reset, but that will create aliasing distortions in huge amounts. EvenVCO goes to great lengths to minimize aliasing distortion, and is quite clean.

EV-3 was the first MinBLEP VCO I worked with, and getting the MinBLEP alias reduction algorithm to work with sync took me a lot of trial and error (and sketching on paper). For someone who is actually good at this it probably would be not nearly as much work.


I mean “just” from the point of view of understanding the concept rather than implementation. I thought that there was some special magic that made it work but then it was much easier to understand than I thought.