Axiom Home Page Forums General Discussion Technical Questions Help with 350 hum?

Thanks in advance for reading:

I have a new ep350 sub, and seem to have an ever present, rather soft, hum. The hum is present when my receiver is off, with the cable removed from the receiver, and even after the sub has gone in to "sleep" mode. With the sub in sleep mode, I can feel a slight vibration on the heat sink of the sub.

Any ideas where to start with this?

Thanks for your help!

Is the sub plugged into the same AC outlet as the other equipment, or a different one in the room? I had a similar problem when I had my twin 350's plugged into a different outlet for whatever reason.

The sub is plugged in to a different outlet - my sub is behind my screen and my receiver is in a different room.

Do you have cable television service?

I had a hum with my ep 500 that completely went away with the Axiom Ground Isolator

FIOS for TV and Internet but neither is currently present in the theater or connected to the circuits that the receiver or the sub are connected to... =(

Different outlet will do it. You can try a cheater plug (but not for permanent install, according to the electrician hawks around here) to see if that gets rid of the hum.

But why would it hum when the sub is not connected to the receiver and in sleep mode?

It is still plugged into an outlet. Just as a test, do you have a long extension cord you could run over to the same circuit, just to see if you get different results?

This may not be the problem, but the IT person in me likes process of elimination.

I agree, next test will be to run an extension cord. Thanks for the idea!

Josh, since the hum occurs when the sub has no connection to the receiver or anything else in your setup, this isn't a ground loop because there's nothing to form a loop. A hum simply because the sub is plugged in indicates a possibly defective sub amp power supply section. Contact Axiom technical assistance directly for further information and possibly a substitute unit.