CVpal buzz during recording

My CVpal is working great, everything was fine until I tried to record audio from my modular: I’ve got a constant buzz on my audio track.
I’ve tried with M-audio and Motus sound interface. Different USB cable. Looks like the 5V from the computer is constantly present.
A friend build one as well and has the same problem.
Did we make something wrong ? Do anyone of you had the same problem ?
It’s a really useful little module and i hope everything would be fine with it.
Thank you for your help !

It’s not a problem specific to the CVpal.

Just that connecting the ground of the CVpal to the ground of your computer will create a ground loop. That’s one thing the designers of MIDI got right…

A possible solution is to use a DI box between your modular system and your audio interface.

Or a powered USB hub with galvanic isolation…they are quite pricey but imho mandatory in a studio environment.

Oh, ok. Thank you for your quick answer. Will give it a try