Hum with Rega RP 10 an Superline/Hicap

Earthing can be a pain when it comes to record players - there are so many variables at play.  It's where a dealer's hand-holding and experience really pays dividends. Of course, Rega don't make it easy by not having a separate earth lead - IIRC they earth through the outer negative of one of the RCA phonos.  

Also consider that the Superline as it uses WBT Next Gen RCA sockets which really only work effectively with the corresponding Next GEN RCA plugs (make sure done up correctly). When you use other plugs it's all too easy to have a poor connection and this is where hum can become an issue.  Much better to use the BNCs.

Best advice here is to work through the problem with your dealer who will doubtless have experienced lots of grounding/hum issues with vinyl over the years.  

Would it make any difference if you switch the 272 ground from chassis to floating? 

There is no real difference if the switch at the back of the 272 is at chassis or floating. I think floating would be theoretically correct... I am surprised that the hum on the left channel is so much stronger. I think, with the hum on the right channel I could live.

ChrisBerlin posted:

Before installing the Superline I have used a Lehmann Back Cube SE phono preamp. There were no problems with hum at all.

And was this with the new RP10?

Chris - Richard's advice above is well worth heeding. Earthing issues can be a bit of a PITA and need a logical think through of grounding paths to ensure this is correct when problems do arise. 

Just one thing to add, i take it that the RP10 PSU and Hi-Cap are located away from the RP10 itself, just to rule this out ?

James

Finkfan posted:

Would it make any difference if you switch the 272 ground from chassis to floating? 

Well its worth a try to see if you hear anything... i.e. the TT preamp is earth grounded along with the N-272 if set to chassis and causing an earth loop.

Normally, as with most if not all Naim NACs if one and only one source is earth grounded ( that is the ground is connected to mains safety earth) then the setting should be floating. If none of the sources have ground connected to safety earth or there are no other sources then you will set the N-272 ground switch to chassis

Simon

Are you using the capacitance loading on the superline?  If the hum is an earth issue it may not help, but I found that hum on the superline wasn't always earthing and adding a capacitance plug (smallest value) was a big help. If it helps but dulls things down the recommended value tends to be 470pF which can be obtained to special order.

I had a similar setup (RP 10 into a Superline that I was attempting to power with a HiCap DR. I tried numerous approaches - positioning and proximity of the units to one another, different cabling and so on. Bottom line: the hum didn't go away as long as the HiCap DR was powering the Superline. I ended up using the HiCap to power the Supernait 2 and plugged the Superline into the aux 2 outlet on the SN2. Works fine and sounds great. 

FWIW, I think it's the RP 10's lack of a seperate grounding cord. Rega use that silly set up where the ground is in the (I believe) right channel cable connection. 

Thank you for your advices. I've placed the boxes in distance to each other. I will try the different capacitance and see how it works. But I do not want to accept any loss in sound quality.

I also think that the problem is caused by the grounding concept of the RP10. Therefore I would be interested in any further experience that anyone has made using a similar setup. I think that other Rega TTs would have similar problems. I've heard that the ground is in the left cinch cable. This fits to my observation, that the hum is much more stronger on the left channel.

Chris - if i understand your setup correctly you have 

RP10 > Superline >Hicap >272 >300

If this is the only The only place a mains earth to signal earth connection is made is in the N272 when the ground switch is set to chassis.

Looking at the RP10 manual, there is no mains earth connection on the PSU so there is no other place for this to happen. You should just need to have one short wire between the Superline ground terminal and just one of the TT RCA plugs outer ring (at the connection to the Superline). You should not need anything else. If this doesn't work then i'd consult with your dealer to check there is no other issue causing this hum. 

James

My Setup is: RP10 > Superline > Hicap > 272 (powered by XPS) > 300. There are two additional sources that are direktly connected to the 272: UnitiServe via Ethernet, Cambridge 752 BD via digital cinch.

@James N: I will try your advice. I've tried to connect the ground terminal of the Superline with the outer ring of the cinch cable (I've tried the left and right channel), but the position of the ground switch of the 272 was floating. At this position the additional earth connection produced a stronger hum.

Does anyone use a RP10, Superline and Hicap without any additional earth connections and has not any problems?

Ok Chris - yes the 272 should be set at chassis 

ChrisBerlin posted:

My Setup is: RP10 > Superline > Hicap > 272 (powered by XPS) > 300. There are two additional sources that are direktly connected to the 272: UnitiServe via Ethernet, Cambridge 752 BD via digital cinch.

@James N: I will try your advice. I've tried to connect the ground terminal of the Superline with the outer ring of the cinch cable (I've tried the left and right channel), but the position of the ground switch of the 272 was floating. At this position the additional earth connection produced a stronger hum.

Hi Chris - The 272 will need the switch set to chassis. The additional sources should not be a problem. The digital connection from the BD is transformer coupled at the 272 so no earth issue here. The only other place could be if you are using screened Ethernet cable to connect the 272 to the network. Worth unplugging to be sure as it would be good to get the TT issue resolved and completely rule out the other sources. 

James

Vincenzo

Moderated Post:  Vincenzo I have removed your post - please ensure you have read and understood forum rules.  Thanks.

Vincé 2 posted:

Vincenzo

I can see what you are doing but i can't see that this would help the OP's problem ?

Sorry.

I thought my experience could help Chris.

Vincenzo

Try removing the Cap plug on back of Superline, record how much hum /RF interference there is. Reinsert the Cap plug and note again. It may be you need a 1nF plug as I am using to cut out the crap. 

ensure that mains plugs are clean,  it is possible there is a loose connection on the supply earth cpc. on the ring/radial.   

The Superline and the HC that have produced  the hum were used boxes. Now I have got a Superline and HC from my local dealer to check,  wether the problem is caused by the Superline and/or HC or other components in the setup. After the installation of the new Superline and HC all hum flow away. 

Thank you very much for your advice. But now I know that there are no general problems in driving a RP 10 with a Superline.