Octatrack MK2 grounding issue

mrmatthewkelly · 2023-05-04T12:20:12.173Z

Hi

My (new to me but 2nd hand) octatrack is creating a lot of hum and ground noise. It’s going straight into my prism orpheus via balanced 1/4" cable from the Main Outs. This is the same route as numerous other bits of gear that have no problem at all. I’ve tried different plug sockets and even a different matched PSU. Also tried it in different rooms over headphones and same problem. Any suggestions at all?

Many thanks

natehorn · 2023-05-04T12:24:04.232Z

I’m assuming you don’t have anything plugged into the inputs?

Is this with nothing happening on the OT or only when it’s playing? Have you tried a new Project? Could be worth doing a full reset on it/clean firmware just to rule out anything software based.

I’ve not come across that issue personally, standard output should be clean as a whistle.

yoyz2k · 2023-05-04T12:29:26.256Z

First as @natehorn suggest :

plug only the PSU into the OT + headphone
new project
plug only the headphone into the octatrack and see if there is hummmm

Then :

plug the 2xaudio jack and see if there is hummm

I know my OT mk1 does not like too much being plugged into USB, does not make humm, but I have some sort of ground loop, like a 5v going on

natehorn · 2023-05-04T12:31:15.422Z

yoyz2k:

USB

Oh yes and absolutely make sure there’s no USB involvement (at least to rule it out), USB is always a noisey troublemaker

mrmatthewkelly · 2023-05-05T19:56:55.812Z

Thanks both! I’ve bought some balanced cables and they seem to have sorted the issue. My inital post wasn’t totally correct - the ground hum noise would only come when I sent the octatrack through my neve 1073 dpd and then into the prism (with unbalanced cables), if it went straight into the prism it was fine. What’s strange is that none of my other gear has this problem going through the neve (synths/guitars etc). Anyway sorted now thanks