Ground hum with Rega Aura

Hi-Fi Corner
1

I currently have a Rega Planar 10/Apheta 3 and Aura on loan from my dealer.

This combo sounds amazing with my 252/300 and Radio speakers, but there’s a loud ground hum audible through the speakers (dial at 9 o’clock, so normal listening level when there’s a record on).

From what I can read on the forum the Aura is supposed to be absolutely silent, which is not the case here.

I’ve had the Danish Rega distributor come by my house twice. They think it’s due to a conflict between the different ways that Rega and Naim handle grounding, but since their last visit I borrowed a Chord RCS to DIN cable from my dealer to replace the standard RCA cables that come with the Aura. The hum has decreased about 6db (similar to the effect of lowering the gain on the Aura) it is still audible at a level that is just not acceptable in this price range.

All Rega items are new out of the box, so currently we don’t know whether the hum is also there if used in another system. The Aura is sitting on top of the brain stack (Fraim) so no large transformers in the vicinity. First time the distributor visited, we tried replacing the Aura with an IFI Audio RIAA that was completely silent, so this (at least to me and my dealer) indicates that there’s a problem with the Aura. However, there’s a long wait (February) to get a new Aura to see if that fixes the problem…

I know there are other forum members that uses the Aura without any problems, so I would like to confirm that a ground hum should not be present at all and that there are no compatibility issues when mixing Rega and Naim.

Best regards,
Karl Johan

2

I’m assuming you’ve tried changing the position of the ground switch on the NDX2 ?

4

Have you ensured the locking collars on the RCA Phonos from the P10 are done up nice and tight?

Also, try an RCA - DIN interconnect from the Aura to the Naim.

Apart from that, I know there are some other members here using the Aura with Naim kit so I’m sure they will be able to advise shortly.

5

This suggests the issue is with the Aura. I had the Aura on demo a few times. I had no problem with grounding with my 552. It should be completely silent.

6

Yes, I tried changing the switch as well as completely unplugging the NDX2 (IC and power)

1 Like
7

Thanks, that was also my expectation. What IC did you use?

8

The locking collars have been redone many times (both by myself and the Rega distributør) and seems to be okay.

I have tried both the Rega RCA cable as well as a Chord RCA to DIN cable between the Aura and the 252. I currently have a SL RCA to DIN IC on order.

9

I used the RCA interconnect that came with the Aura. I also used RCA-DIN Hiline. I had no grounding hum with either.

10

Seeing that you’re in Denmark, check the mains earthing, especially if you’re using any shucko type plugs, which won’t earth into regular Danish sockets. Check also the polarity of all the mains plugs. Be sure they are all the same.

1 Like
11

I agree that it might be a local (Danish) problem.

I have checked that the polarity is the same on all cables. All Powerlines uses schuko plugs into the Ansuz power distributor. The cables from the Ansuz to the wall socket also uses a schuko plug with a ‘schuko to three pin’ adapter to the wall socket that has three pins.

I live in an older building but the top floor was completely redone 15 years ago so all electrical installations should have earthing on a separate wire - at least all sockets are for three pin plugs - whereas installations in Denmark are not required to provide the ground pin. I might have to check with an electrician if it has been done correctly.

1 Like
12

Thanks, that’s good to know.

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