SN3 hums when turntable is turned on at the socket

[MarkLennon]

Thanks for your advice.

[IanRobertM]

This…??

I have run Rega (Planar 2)and Linn (LP12) TT’s with a range of Naim Preamps, without any such problem. The earth from the arm goes to the pre. The TT motor is earthed via its mains plug. This is in the UK.

[MarkLennon]

Yes that!

[IanRobertM]

You just picked it up…? New…?? Call your Dealer…!!!

[MarkLennon]

It’s a Grade A so might have issue then but new to me.

[james_n]

I think its the lack of signal ground to mains earth connection on the SN3 compared to the Uniti 2. This can cause issues with the switching supply your Project TT uses. Try connecting a piece of wire between the SN3 ground post and the outer of a DIN socket and see if this stops the hum.

[IanRobertM]

Still same. Call your Dealer… Do Not Pass Go, Do Not Collect £200…

[MarkLennon]

Thanks I will.

[IanRobertM]

And… please… report back… Lets learn from this…!!

[MarkLennon]

I’ll hook up my Uniti 2 to it tomorrow to see if there are any noise issues there.

[MarkLennon]

OK thanks will give that a try.

[james_n]

See here -

Hum/buzz noise supernait 3

Assuming it’s only the RME connected to the SN3, I suspect the RME uses a switching supply which can give issues with Naim amps. You want to create a connection to mains earth from signal ground. You could do that via a mains plug earth pin to the ground connection (signal ground) on the back of the SN3 as per the quoted post. Alternatively just take a length of wire and connect it between the ground connection on the SN3 and loop it around the outer metal shell of one of the DIN sockets. The D…

[MarkLennon]

I haven’t tried this yet. Interestingly when I connected the Uniti 2, the buzz disappears completely but reappears if I disconnect It.

[james_n]

I take it you mean you have the Project TT and the Uniti 2 both connected to the SN3 ?

If so, with them all connected, change the ground switch from chassis to floating on the Uniti 2. Does the buzz come back ?

[MarkLennon]

Yes with the TT also connected.

Yes it does when on floating but it’s much a quieter buzz.

[james_n]

That makes sense. So just use the system with the Uniti 2 connected and the ground switch set to chassis. If you don’t have the Uniti 2 in the system (or a Naim streamer), then you’ll need the extra ground wire on the SN3.

I think you mentioned previously you were going to use the Uniti 2 for now before changing to a dedicated Naim steamer ?

[MarkLennon]

Yes but not for a while. The vinyl sound is on another level now which what I was I after and it drives my P3ESRs a lot better too. Even the Uniti 2 is sounding better.

Thanks for the advice.

[james_n]

Good stuff. Enjoy your new amp

[IanRobertM]

@MarkLennon

it’s much a quieter buzz.

Progress - and more understanding. Welcome to the madness of Turntables…