I’ve noticed on myPO33 there is a hum/buzz when an external source is plugged in.
This can be any audio device, even another PO. it happens whenever an aux is inserted, even when the other device is muted or nothing is plugged in the other end.
It’s noticeable but you can’t really hear it over music. Still annoying.
To reproduce - just plug in an aux to the PO input. Noise instantly audible even at sensible volumes.
It doesn’t effect records of samples. Is this usual? Never heard it on my other POs.