Sunday, 4 May 2014

New DIY project: standalone Juno-60 chorus clone

I sold my JX-3P a while ago, but I found out I missed its chorus.
So I decided to clone it, and since the Juno-60 one is often described as better, this is the one I chose as a basis.

All components are still available, except maybe the BBDs, but you can source them from chinese ebay sellers, and they seem to be genuine.
All I did was to change input & output stages, and use a LFO design inspired from the BOSS CE-2, the remaining parts stayed mostly the same.

Enough said, here's the finished PCB:

And here's how it sounds (base sound from my Prophet 600):

Some more files: (pics, schematics, FLAC demo)
And, since it's a free/open source project, the project page:

The debug phase went mostly well, but I still have to update the PCB from the fixes I made on the schematics, so better wait a little if you want to build one!

PCB update done, should be ok to build!

I compared it with a Juno-60 recording and found out the chorus was a bit weak on mine. Turns out I copied a resistor value wrong in the BBDs output stages.
I fixed it and now it sounds really close to the original!

Some more changes to input and output levels.
Here's a second demo on polyphonic & arpeggio sounds:


  1. Nice work! I was thinking recently about a Juno 60 chorus clone. Going to take a look at yours!

  2. Great project, thanks for sharing! When i can spare more time, i will certainly build this.
    One question - i know the original Juno chorus has slight bass boost - makes the signal "thicker", besides the chorus effect itself - does your clone have this effect too?

  3. Hey, nice stuff. It sounds VERY good! But where can i find the parts list and stuff? Seems like one of the above Links is broken :/