REL subwoofer hum


I own a REL stadium III, and have owned it for some time now. Just recently I noticed that it will produce an audible (although low level) hum when I turn my system’s amplifier off. I have the Stadium hooked up in the recommended manner: I have it hooked up with the neutrik cable to the Speaker B terminals of my amplifier. Speaker A terminals are occupied by my Sonus Faber concertos. When both sets of speaker terminals are on, the sub is quiet. When I turn off the B speaker terminals, or turn off the amp altogether, a low level Hum is output by the REL. I have not noticed this hum before and believe it to be a new occurrence. However, I guess it could be a ground hum. My main amplifier, and the REL are plugged into two different outlets, both outlets have quality AC filters/surge protectors, and I use the stock power cords for the amp and REL. Should I alter my hookup method? Would better power cables help? I really don’t want to have the REL serviced as, I’m sure you know, it weighs 110 pounds, and I don’t want to have to move it. If it is a so-called "ground hum", how do I alleviate it?

phoenix469
We had enough clients with this humm problem and others like; distorted audio, static noise.

Unresolved by REL we recently traced out and examined the schematic and found several simple mistakes.

About the humm. The balanced speaker level input is simply miss designed. As a result it does not reject noise or hum. Solved

If using the high level input, there is distortion at anything above watt. A second design flaw, solved.

At high levels using any input the sub sounds like the amp is clipping or the woofer is bad. It can even sound like a flimsy cabinet. A third design flaw limits undistorted ouput to few watts. Again solved.

The woofer, amp and enclosure are fabulous. Once the electronics are overhauled the sound is too.
Had similar problem and was convinced it was some high priced item but it ended up being my DVR.

My Stadium III with speakon is silent.
I have had similar problems with my REL G1 subs to what Chrisautosound has described. I have been through 3 subs. The first 2 subs had loud distortion while playing music when phase was switched to 180. OK with 0 phase setting. With LFE, there is loud distortion when any low sounds are played. Volume does not need to be very loud.
Chrisautosound, what did you do to correct these problems?
REL/Sumiko has given me a third sub which appears to be functioning properly. They are sending me an new amp board for my second sub.
Steam3642 - Great advice. I've been fighting this with my Strata iii and BAT VK75SE (only a problem when amp is ON). The BAT is also fully balanced dual differential and when I wired to right terminals only, buz is gone and bass notes from sub come through clean and pure . . .Thanks!