Author Topic: Hum in subwoofer: fixed by disconnecting ground side of subwoofer trigger cable  (Read 337 times)

Offline elbow


In case it helps someone else: I had a litle bit of hum in my subwoofer.

My mains neutral is probably noisy since I have a grid-tied inverter feeding power from solar and also lots of switching PSUs.  Since the inverter is a switch-mode style it does make noise on the mains and RF interference too.

Neither my subwoofer or my AV amp connects to mains earth (2 pin connector).  So my first thought was - how can there be a ground loop? - nothing is grounded.

Anyway - I discovered that the hum disappeared if I disconnected the trigger connection.

So I guess I did have a ground loop between ground side of the trigger wire and the phono.

And indeed breaking the braid on the trigger cable cleared up the hum.

Trigger still works - signal is working with reference to the ground coming in on the phono connection.

Maybe that will help someone.  Or maybe its old news...