Axiom Home Page Forums General Discussion Technical Questions Sub hum won't go away

Need some additional troubleshooting steps as the standard ones aren't working. Unless I'm doing something wrong, which is very possible.

My system had been playing for several hours when the sub started humming very loudly. I shut everything down (switching off the power on the EP500) thinking it may have gotten hot or something. So, I waited an hour or so and switched the 500 back on before turning on the revceiver. The 500 started back with the hum. Ground loop issue? I unplugged the line in on the 500 and it still hummed. I then moved the 500 plug (all components are plugged into a Tripplite HT10DBS)to a different circuit. Still she hums. This is with the line in disconnected from the sub. I then disconnected the incoming cable connection from the HT10DBS. It feeds into this before it feeds into the cable box. Still she hums. I then disconnected the outgoing cable from the HT10DBS that actually feeds the cable box. So, incoming is disconnected from the HT10DBS and the outgoing is disconnected. The line in on the sub is disconnected and the plug is on a different circuit via a construction grade extension cord. I even tried using a two prong plug to eliminate the ground prong. No dice.

Any suggestions? I was planning to head to the store to get an isolator, but if the cable is disconnected from the equipment and it's still humming, would it make a difference?

This really blows as I was planning to watch Miami Vice the movie tonight.

All suggestions are appreciated.

Edit: Meant to add that I also removed the chasis ground on the back of the 500 and it still hums. Just to clarify, there is nothing connected to the 500 during these tests.
Stymie

Sty, from your description it appears that you've taken all the steps to identify/eliminate a ground loop and that isn't the problem. Especially since this suddenly developed after playing for quite a while it would seem to indicate a defect in the sub amp. Probably you should contact Axiom directly as to how to proceed.

Thanks for the reply John. Contacting Axiom was my next course of action. I was hoping that I missed something though.

Gotta agree with John. Give Axiom a call. Sorry you have to go through this. The good news is, Axiom will take good care of you.

Stymie,

Have you tried step 8 in your manual?

Quote:

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GROUND LOOP:
If your subwoofer is producing a 60 Hz hum; remove the Chassis Ground Screw. If this does not solve the 60 Hz hum, call 1-866-244-8796 or consult the full manual at www.axiomaudio.com/manual_ep500600.html

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This may take care of it.

Shawn:

Stymie wrote:

Quote:

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Edit: Meant to add that I also removed the chasis ground on the back of the 500 and it still hums.

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So it looks like he DID try that....

Well, there you go! I read his post twice and missed it both times. I really need to SLOW DOWN and absorb everything I read before replying.

I opened a ticket with Axiom this morning and they're going to get back to me with the next steps. Hopefully it's not fatal.

Maybe I should have gone with Superman over Miami Vice.

So have you tried removing the ground screw as mentioned above?

It's been said 3 times he already tried removing the ground screw.

Hey man, any chance you tried removing the ground screw.

Have you ruled out your house wiring? Maybe run a very long extension cord to your neighbors to see if you still get the hum.

I know for sure that I wouldn't get the HUM at the neighbours. But then again, I don't get the HUM here either.

Have you tried turning the sub off?

Yeah, that 80's guy is starting to get up there in age. As am I, ha ha

You may want to try & unplug your cable box. It's fairly common in my area to have this be the problem. If it goes away, you may want purchase one of these Ground loop isolation transformer Works like a champ everytime for us.

Does the sub hum if you disconnect it from all the audio equipment ? Don't play with the levels, leave everything as is, just disconnect the audio cables.

EDIT -- in the original post it said the sub hummed even when the line in was disconnected. Folks, I don't think this is a ground loop.

perhaps it doesn't know the words......

Well, the 500's amp has been removed and is on the slow train to Canada.

I've been complaining to my wife about missing the 500's contribution to movies and such and she indicated that she couldn't tell the difference!

Hmmmm..... maybe I should get a second 500. I think she'd notice two of 'em.