Strange Sub Hum (1 Viewer)

[ChuckyMan]

I am using this Nobsound NS-03G Subwoofer Amplifier to power my passive subwoofer. It works great...mostly. For some reason, every so often, I'll be playing a game or watching a movie, and then all of a sudden there is a loud hum or buzz. Like...Thummmm. This noise is constant until I unplug the amp and plug it back in. I checked the 3.5mm input, taking it out and putting it back in. The sound doesn't return until the next day.

I twisted the 3.5mm input cable, tapped it with my finger, and noticed the same kind of noise, which is almost like the sound you hear when you plug in an electric guitar...only THIS noise is constant.

Any ideas ? A better quality cable, perhaps ? It would have to be an RCA to 3.5mm mono cable.

 

[Dave Upton]

It almost sounds like a ground loop hum - which is caused by the ground of your sub amp having a different potential than another device in the chain. Ebtech makes a product called the HumX, that works pretty well to resolve this - but for now, you might want to try unplugging the input entirely to see if the sound goes away when you do so.

It's possible the 3.5mm input is the culprit, but the persistent hum is usually a bad capacitor or a ground loop.