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
I have removed the hum when the Kw -500 is turned of by connecting the 3 wires of the speakon connector to one channel of the musical fidelity , instead of running the red wire to the left channel i have connected red and yellow to the right channel along with the black ground wire. Not sure if this is an acceptable solution but does not appear to be having a negative affect on the amplifier
So all 3 wires are now connected to the right channel and no hum when powered down and m/f and rel works as normal when powered up.
I have the same problem. I have a new rel g1. Expensive sub for sure. Talked to sumiko and they helped but still have that dam hum. I've tried everything. Using ayre mono mxr. Fully balanced system. Even when I ground to preamplifier. Still get the hum. Im about to build out a critical listening room. In the design stage so I might just have to deal with this. I hope the rel is wired wrong on the inside. Any help.
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.