synchrodyne techniques

synchrodyne expander

what if you take a switched capacitor filter and drive it with a phased-locked loop based clock? and what if you add the ability to control the PLL or inject your own clock? you get the wmd synchrodyne module.

this is one of those modules that were designed in the spirit of deep exploration but without setting you on a certain path - you can definitely use it as a filter but there are so many other things you could do with it. it’s a patcher’s module, giving you access to internal workings and wide parameter ranges and therefore the total freedom to experiment. and then you get the expander which continues in the same uncompromising spirit instead of trying to tame it. i think it deserves its own thread so that we can share techniques and explorations.

we’ll definitely need the manual:
Synchrodyne_Manual_Print_306c41a9-a973-4c05-9588-7dca8bccbd9c.pdf (2.3 MB)

and the expander diagram:
Synchrodyne_Expand_Quickstart.pdf (2.0 MB)

wiki article about the phased-locked loop: Phase-locked loop - Wikipedia


I recently did a Synchdroyne deep dive because its odd behavior had kind of confounded me, and wrote it up here:


i was hoping you to see you in the thread! your notes have been really helpful (and i’ve yet to explore the many great patch ideas).

i went through the initial “turn everything wildly” phase and now trying to go back to the basics and explore it more methodically, so starting with just using it as a filter. i love the dusty/crackly/organic aliasing sound you get with it and the fact that it’s similar to the sound you get with sample rate reduction / bitcrushing but seemingly more powerful and alive (and now that i’m thinking about it, i should try putting audio through a S&H driven by a couple of square oscillators).

really fun combining the two oscillators using the expander, and i think the expander should enable using your own clock without it being OR’d with PLL1 by setting it to VCO2 and setting PWM so that VCO2 just stays low. but i should also try clocking it with 3 oscillators, particularly putting an external oscillator through the filter and multing it to clock 3 input.

even with the expander i find i want to have some helper modules around - as you mention, the VCA gain is so high i have to keep it really low, so an external attenuator helps. and a mixer or a CV-able crossfader to combine the various outputs. i’ve surrounded it currently with cold mac and moddemix which frankly might be just too much to explore…


I had so much fun with my Synchrondyne + Expand. I don’t know how much usable material I recorded while I had it, but the learning and process was the joy. Someday I’d like to pick them up again if the opportunity presents itself, as unlikely as that is. (I purchased the pair originally from @trickyflemming and then stupidly sold them on Facebook after making a bunch of videos about them.)

It’s rare to have a set of modules that is essentially a full system that doesn’t make a lick of sense on the surface. No normal person looks at that convoluted mess and understands it out of the box, but damn if it isn’t fun to figure out.

I really liked the Expand’s outputs, especially the PLL triangle output. Your palette there is a perfect set of complementing modules.


Honestly that PLL triangle output is the main thing I miss from when I had both the first time around.