Continuing SN3 humming when connected to AV receiver

Continuing the discussion from Supernait 3 humming when connected to AV Receiver:

Hello All,

I also got a Supernait3 for demo at home, and I am facing ground issues, means humming, and issues connecting my Marantz AV7704 in AV bypass.

Reading your post, and Understood that xfilian had a faulty unit, is this the right understanding? Can you please explain what your shop has done for you, I did not get it,
I have the feeling this is also my issue.

Many thanks

Message from xfilian from the previous post:
Sorry it has taken a while to reply but I have been otherwise occupied.

I now have a new Supernait 3 and the demo unit has been taken back to Sevenoaks Sound and Vision. They kindly made me up an earth cable to go with my new amp as I had informed them of the humming issue. Got the new amp home, plugged it in and guess what - its as quiet as a mouse with no hum whatsoever. This is without an earth cable. A bit perplexed why one amp would produce the hum and another doesn’t but whatever - I have now have a hum-free Supernait 3 and could not be happier. Thanks again for all the advice.

If it’s a demo unit, start by checking the grounding switch at the back is set to floating and not chassis.

Hi Robert,
there is no such switch option with the SN3,
only the AV bypass switch, and a ground connector (Which I guess is for TT?)

!? Surprising, every other amp has one.
Do you have anything else connected?

Pretty sure the grounding switches are on the source components, not the amps.

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Yep. Network players and the all in ones (Uniti ranges) have ground lift switches to give this option if other components already provide this link - a Naim CD player for example. The amps (apart from early Naits) don’t connect signal ground to mains earth.

As @robert_h mentions in his post, more information about what else you have connected to the SN3 would be useful.

I’m going mad, I swear something has the floating/chassis switch but it’s been magically removed from my sn2 and ndx2.

Found on uq2! And dac v1
And ndx2 on the right hand side.

I need a lie down

Should be one on the NDX2 ! :grinning:
Below the analogue outputs

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Hi again
I have a Rega P3 with PSU on the SN3, as well as Rotel RCD991.
Then the Marrantz AV7704.
On the Marrantz I have a Cambridge Azur BD751, cable tv, and apple TV, and Xbox OneS

i have found no ground switch on the Marrantz AV receiver, Rotel CD or Cambridge Bluray, or SN3.

I would disconnect everything, then add to the sn3 one by one, marantz last. Then add one by one to the marantz. Ascertain at what point the humming starts. Can you isolate it?

I got a supernait xs3 for test at home, just connected my Marrantz AV7704 and got the result that none of the 2 main speakers works, which is more consistent, but problem is there.
I will now proceed as you suggest to remove every of my gears and cables and test one by one.

also, do you suggest I connect the ground screw on back of the sn3 or xs3 to the ground screw on my marrantz av? they are used for turntables normally.

Hi again,

As you suggested I unplugged every single cables, powerlines, and tested with the minimal connection. Tested with cd, vynil, then Av preamp…

tests done with the Nait XS3 and SN3 both. And everything works perfectly with the Nait XS3, so SN3 has some problems clearly. I will bring it back in the week!
Btw I tested the nait XS3 with the nd5 xs2 streamer on Qobuz, that works pretty well!

Thank you all for your help and suggestions,
Enjoy your sunday in music

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