2. misc-audio
  3. 1167277489

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
bflowers
80 posts
 
Mine has a hum all the time and my amp chassis doesn't have a ground on it. What to do? Called Sumiko once and they told me to unscrew one of the screws on my amp to connect. Called the amp manufacturer who said that would immediately void my warranty.
artmaltman
769 posts
 
Alas, I still do have a slight hum under the one circumstance that you describe: when the amp is powered off and the sub is powered on. Not a huge problem of course but disappointing.
Art
steam3642
124 posts
 
Hi there i have the same problem with my Musical Fidelity Kw -500 using a Rel R-305 subwoofer , turn the Musical Fidelity of and the hum starts turn it back on and i wait 30 seconds for the preamp section to kick in and the hum goes and the Rel works as per normal , i use the speakon connector , strange thing is i have also got a Redgum Audio RGI - 120 Integrated amplifier as a spare and when i connect it up the same as the Musical fidelity Kw -500 i have no problems and the Rel has no hum , so my hum problem is isolated to the Musical Fidelity integrated and i have also tried grounding it to the chasiss to no avail . Anyone had a problem with hum on M/F amps ?
tmsorosk
1,013 posts
 
60hz hum or what some call a ground loop problem is common with subs . Audioquest has a sub interconnect that has a ground lug built in , it solved the problem for me . I've not heard of chassis grounds ever harming a component or causing a warranty problem .
Floyd Toole said everything should be grounded to the preamp , to get the lowest noise floor possible .
steam3642
124 posts
 
I tried again with another wire combination on the
M/F kw 500 , as per the Rel manual : red wire to right channel positive , yellow wire to left channel positive and black wire to negative left channel . I found that if i connect all 3 wires to either the left or right channel the hum stops when the m/f is powered down and runs as per normal when powered up Rel appears to operate fine , would this be due to it having a bridged/dual differential internal design , apparently both left and right channels are
open/hot aand feature a bridged output.
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