Hi all, hopefully some teckies can advise on this.
I have a ground loop issue with my Rel S510.
My system is Pontus 15th/Meridian 506/Naim 282/250DR/ Supercap 2 (NonDr)/Sopra No1/ Rel S510
The Rel is connected via high level to the speaker posts. I’ve had a Rel T9X connected the same way with no issues but have a ground loop hum on the S510
Following a conversation with the dealer I have tried wiring the rel to 1 speaker with no luck, I also wired the rel to the earth terminal on the 282 with no luck. they also lent me a high level cable specifically designed for Naim/rel which plugs straight into the 250dr, which hasn’t solved the issue.
If I disconnect the input from the back of the rel there is no hum.
With the system powered down, but the rel switched on, if I remove the Meridian 506 CD player there is no change, but if I remove the Pontus the hum increases.
Likewise if I remove the 282 from the system (powered off) the hum increases.
I have tried to change the power source for the 250DR by plugging it direct into a wall socket with no improvement.
The only issue I’ve had in the past was when I had a HCDR which had a slight hum that I just lived with. I replaced the HCDR with a Supercap 2 which had just been serviced when I bought it, and there was no hum.
I haven’t made any electrical changes in my home and I’ve tried the system with and without an Isotek Evo3 mains conditioner.
More often than not, hum from a Rel sub can be caused by the high level lead being very close to the subs power lead. Make sure they are not close to each other and certainly not coiled up together.
If it won’t reach the same socket as your system try connecting it via an extension lead to see if it’s a ground issue. There may be a potential difference.
With the sub disconnected, do you hear the hum at all (likely very much lower level than to the sub)? Maybe best to listen for difference with and without being Pontus attached. If yes then that suggests the issue has nothing to do with the sub, but grounding associated with the Pontus, the sub making it very prominent.
I don’t know if this will help you because ground loops problems and solutions vary.
I have a six-pack of REL S/510 connected to my speaker (not amp) terminals with high level cables (REL Bassline Blue). I initially had a ground loop problem with the RELs.
My solution is to connect just the positive leads (red/yellow, which are combined since I have stereo pairs) to the positive terminals of my speakers, and I run the black (negative) leads back to my grounding station (a Clearaudio Terra) which also has grounds from my turntable and phono-stage connected.
You said you tried the bassline blue for naim cable attached to the amp and still had hum. That was true also on my 510 When i used an olive 72 preamp.
The solution was to use that cable attached to the amp but the black ground wire needed to be attached to the phono ground on the 72. I did this by cutting the black wire, stripping the end a bit, and then using a wire cap to extend it with a foot or so of old speaker wire. The speaker wire was then grounded on the 72 phono screw.
Interestingly when i replaced the olive 72/hc with a 332/npx i was able to ground at the amp as rel specified with no issue. This was necessary because grounding at the nvc-tt had hum. In other words the NC series and Olive series needed opposite solutions to solve the hum
The cable I have is on loan so I can’t strip it back, but I’m sure I can improvise a way of running a wire from the connection at the back of the amp to the earthing terminal on the 282.
I hope you get it sorted. Ground loop issues can really be the devil.
Here’s something interesting I discovered today. It seems I don’t really need to attach the black lead of my subs to the ground station anymore. What changed? I removed my NDX2/XPS-DR from the system. I wonder what might have happened if I changed the ground lift on the NDX2?
I understood that. What I was suggesting is yes, silence the sub, and listen to the Sopras. Turn the volume up a bit. Is there some hum with the Pontus and not without? Yes, it will be far less prominent than with the sub, maybe quite faint, but is it there? If hum is indeed evident with the Pontus and not without (and no sub), then the issue may simply be the Pontus grounding, with the sub emphasising it, ditto the preamp (I’m unclear whether the Pontus go es through the preamp?). That may mean it is nothing to do with the sub or its connections.