Midi bleeds parasites into audio

Hey everyone, I use the pyramid as main sequencer, but it is synced to ableton (because I multitrack my synth into ableton, so I sync the tempo so it’s on the grid)

In the past I already experienced those kind of parasite (wich seems to comes from the computer when the power supply is used, and this kind of ground loop bleeds thourgh the USB, then to the midi cable, to the pyramid, then to everything else) ; those parasite are unstable, (not like a “steady” hum) ;

I can’t unplug the power supply, and I can’t unplug the midi sync to the pyramid (well, I can but I won’t unless there is no other ways) ;

Last thing, some of my synth are more sensitive than others (monotribe and MFB522 both have this)
Most of my synth use TRS but not all ;

I know a bit about soldering (maybe I can solder stuff to the ground somewhere ?), I can also buy devices or new cables if necessary ;

anyone have an idea ?

Thanks :slight_smile:


Forgot to add, parasites are likely to occurs if my fingers touch the metal case of the pyramid

does this help?



Try using the DIN MIDI connections instead of USB. The DIN MIDI ports use optical isolators to avoid exactly this problem.

1 Like

Thanks !

I already use midi over USB, but my sync start with my computer, at the very begining it is a usb/midi interface and the parasites goes through the computer to the USB through midi ; I try 3 different midi interface with no luck ; however the link creepy pants posted seems to help a lot, I plug the computer power supply on the same wall socket as every gear involved in the midi chain, and the ground loop somehow disapear ; Electricity and ground loop are so esoteric sometimes ;

Also at least 2 of my synth are not isolated ; the “optical isolator” in the midi port you mention is just the ground, and it’s one of the 5 midi pins ? Or it’s a piece of circuit board between the midi port and the main PCB ?

Cheers from France :slight_smile:

Thanks, Yes it does ! I plug my computer into the same wall socket of every of my gear, the ground loop disapear (for now, I’ll update here if it’s stable) ;
I would never have thought to try that (I know how to solder but I’m not electrician at all, I just know how to blindely follow instructions) ;

Thank you Creepy pants, it’s not the first time you help me :slight_smile:
hope everything is fine for you :smiley:

did you keep exploring your “random pattern generator process” ?

Cheers !

1 Like

Plug all your gear into the same wall socket did solve the issue, absolutely no ground loop anymore !