There is a difference between electrical safety earth, which is casing/metalwork where that is connected to the earth wire in manufacture, and signal earth, which some units may connect to the mains supply earth, and others not, and runs through the entire signal chain from source to speaker (with the exception of balanced power amps like the NAP 500 where it doesn’t go through to speaker). Connection of signal ground to mains earth is only wanted at one point in the chain oherwise causing earth loops and potentially hum. It seems you now need to hunt out where a second connection is happening, the sub being implicated, though disconnecting from mains earth could be at either ppoint. Fromwhat you’ve said one might be the preamp. Do either the sub or preamp have a switch to select earthed ground or not? (Might be called something else(
You need to earth from the Rel to Chassis ground on power amp. Use a cheap phono earthing wire from one of screws on back of Rel to your power amp.
Hum will be gone.
Good point, lack of earth ground can also result in hun, stopping when grounded/earthed, though not then an earth loop.
I had problem with my S812s but only when connected to the AV amp via low level connection. High level connection had no issue direct to speakers.
I did alot of research, watching Rel videos from their boss John Hunter. And he said in the event of any hum go to Chassis ground. Just undo a screw on the back slightly and earth wire from there to back of power amp.
I second what DanM says about watching all of john Hunters videos on youtube that discuss the grounding issue. Also i think he has some posts on the Rel site itself about grounding.
In one video or another John has gone through just about every grounding scheme known to mankind with the possible exception of grounding directly to the ground screw on the wall outlet! You can literaly make a list of all the possibilities and work your way through. Fun stuff. NOT!!!
Good news is when you figure it out it will be great. I love the Rel. one more thing…my dealer told me he has more issues with the 510 than any other Rel when it comes to grounding. The problem for him was that he liked the 510 the best with the exception of the much higher priced 31 and 32 reference models. So he just persevered and worked through the grounding issues with all his customers one by one, rather than go with a different Rel that was less likely to hum. So i am not suprised that your model 9 worked fine.
As an aside, I wonder if it’s usually REL models with class D amps that tend to have issues with hum?
I only had problems with R-218s, but never with the T-5, T-5i or Storm III models.
There is no reason whatsoever why the amp class would make any difference to ground /earth related hum
No, has nothing to do with using class D amps. It’s just system configuration. Grounding issues can be a mystery sometimes. For example, removing the NDX2 from my system eliminated the hum from my RELs. I had solved that before, but now the solution seems unnecessary. Who knows what will happen when I integrate my new DAC into the system?
Okay, it’s probably just a coincidence. Though it did make me wonder if something about REL’s class D implementation makes it more susceptible to hum issues.
No, because I’ve had it both ways with their Class D amps. And as stated before there’s no reason a class D amp should be more problematic than class A/B, etc.
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