Subwoofer buzzing even without connection to receiver

lkir1

I have a Polk RM6000 sub/sat set plus a Yamaha receiver that I have had for about 4 years. It has performed flawlessly until recently when the sub started buzzing constantly.

I unplugged the coax lead from the sub but still the buzzing was there. The sub was plugged into a Belkin surge protected powerboard with some other devices including my tv and receiver - I unplugged everything except the sub but still the buzzing is there.

Next I plugged the sub straight into a totally seperate power socket (without the powerboard) and still it buzzes.

It makes no difference if the sub is connected to the receiver or not - the buzzing is constant and never stops.

I have read about the grounding issue with subs and receivers but I don't think that is my problem here because the buzzing persists without connection to the receiver and without the receiver even being plugged into the mains.

Also not sure if this is a clue but I noticed when I was watching a movie the other day that in some particularly bassy sections, the sub crackled a little. I turned the sub volume up higher and crackling was even more pronounced.

Do I have a damaged sub? Has it blown somehow?

I am not too experienced with all this stuff so any help would be highly appreciated.

ben62670

Welcome to Club Polk. Try to plug the sub into another outlet like a bathroom outlet. These are usually on their own circuit. Subs run pretty low, and AC is 60hz so noise can be amped pretty good by a sub. Also what level is the gain set to on the sub?
Ben

danz1906

Try lifting the ground with a cheater-plug.

CowboyRJB2

when my wife ran the blow dryer my old velodyne used to buzz.... I gave her a perm!

CowboyRJB2

Just had a second thought. it wouldnt be a ground loop problem, would it?

lkir1

Wow - thanks for the quick responses. I will try some of those suggestions when I get home from work and report back later.

One question - if I use a "cheater" plug, will there be any increased risk to the sub if there is a power surge?

ben62670

lkir1 wrote: »

Wow - thanks for the quick responses. I will try some of those suggestions when I get home from work and report back later.

One question - if I use a "cheater" plug, will there be any increased risk to the sub if there is a power surge?

Not really. If it shorted to the case of the plate it could be a shock hazard.

Mike21

Hi Ikir.

If the suggestions above (incliding the perm) don't fix it, you might take the sub to your office or someplace else outside your neighborhood. If the problem goes away then you'll know its dirty power coming into your house.[ A power regenreator MIGHT fox this, but these things are expensive. Probably cheaper to buy another sub.] If the problem persists then you'll know its an internal problem with the sub.

If so, it could be a ground loop caused by a loss of ground inside the sub. This could be caused by something as simple as a loose screw touching something its not supposed to. If you are handy, you might loosen the plate amp and see if anything is loose or seems out of place.

If you are still under warranty you could send it back t0 the manufacturer or seller for repair.

Or, you might try a gound loop elimination device like the Hum-X ($90 @ Audio Advisor.com).

Good luck.

Mike

CowboyRJB2

I had a sub hum due to a ground loop problem with the cable box hooked up to my receiver. Recommended by Polk I went to Parts Express and bought a ground loop isolator for $10 and it worked perfect. Best $10 I ever spent... Here's the link to paste in your browser. Hope this helps
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=265-012

lkir1

Well yesterday I went home with the intention of trying some things on the sub...I plugged it back into the wall and turned it on...heard a fairly loud pop, then very loud buzzing. Turned it off straightaway and then there was a faint burning smell coming from the sub.........:eek:

I waited for a few mins and plugged it in again and the loud buzzing came out instantly.

So it seems like it is totally screwed now.

I am going to take it to a repair place and see what they can do for me. I am pretty sure it is out of warranty and the store I bought it from has closed down anyway.

Thanks for all the suggestions though. If I manage to get it fixed I might post back here if anyone is curious.

Falcon01

I had a sub that was doing the exact same thing as the original poster and it turned out to be a resistor (or capacitor was it?) that had gone bad.

From what the tech told me this things job is to cleanout the noise in the current and this thing stopped doing it's job. He replaced the resistors and the noise was gone.

lkir1

Turned out it was a faulty capacitor causing the buzzing. On top of that something to do with the power supply was replaced as well.

Cost me way less than the cost of buying a new sub so I'm pretty happy it's all resolved now.

Falcon01

Glad it worked out.

quadzilla

I had a M&K V-125 that buzzed. After reading some of the posts in this thread, I decided to get adventurous and pull the plate amp off for a look. Sure enough, it was fairly obvious that one of the caps on the power circuit had leaked. I replaced them both, and now that sub sounds incredible. I'm going to have to replace the caps on the other V-125 just so they'll match, as the upgraded one is now quite a bit louder at the same volume knob position.

So thanks to those that made is sound like a fairly easy repair. It really was.