Earth switch position with Superline

Hi-Fi Corner
1

Hi,

I’ve a Rega P6 with a Superline powered by the 552, and a ND555 connected to the 552. Does anyone know if I should set the earth switch on the ND555 to default or floating?

Thanks.
Laxton

2

So long as you aren’t using anything else such as a Naim CD player, I would be inclined to switch the signal earth of the ND555 to chassis.

3

Thanks Richard.

What if a Supercap is added to the equation to power the Superline? Should the switch still remain at Default?

Thanks.

4

Chassis.

5

Thanks Yeti.

6

I have another Naim source in the form of a DVD5 which provides a signal earth for the system but if I use it for that and set the ND555 to floating the ND doesn’t sound nearly as good as when it is providing the earth and the DVD5 isn’t connected by its analog output. Connecting the DVD5 and an ND555 set to chassis by hilines is plainly wrong from the sound of it. I ordered a digital cable to feed the DVD’s output into the ND BNC input which seems to give the best results all round.
In my setup the ND likes first place on the multiblock but that’s one for experiment, there are other ideas out there.

7

Hi Yeti, Presumably you mean (one of) the 555 PS is best in first place nearest the mains input?

As ND555 has no mains input I find it odd how the attached 555PS can know it is to provide the system ground. With nDAC the signal ground can be dealt with internally and extended to the 555 through the Burndy. I also find it a weakness that ICs carry signal ground to the preamp - Burndies look beefy with rigid connections, but a floating DIN signal pin!

Rega use a form of (galvanic) isolation in their Aria phonostage, which allows static to discharge from the cartridge. It must work because I have never had a problem.

Phil

8

I only use one so no confusion as to which is signal ground but that might be a factor in my preference for a single ps, I didn’t pay attention to where they were plugged in at the time I heard the ND555 with two.
I’m not getting drawn into the why of it, I don’t have an explanation as to why plug order should matter I merely observe that in my system it does.

10

It doesn’t need to Phil - a 555PS will carry chassis ground (i.e. mains safety earth) via the Burndy (connected to socket 1) to the ND555 chassis. In the ND555 this connects to signal ground as the single mains earth to signal ground connection (which can be lifted via the switch if needed) as is usual with a Naim source. With dual 555PS setups you will still only have one 555PS carrying chassis ground to the ND555.

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11

Thanks James. I hadn’t thought of the Burndy carrying mains earth, but it must. Not sure whether the nDAC + PS works this way (same Burndy?) as the PS is optional and so it must have the option at least to use the nDAC mains earth. Does the earth switch control a reed relay?

It might seem a bit pedantic, but if you want to use the plug order to set the system earth you need to know which plug will carry it!

One other point. NDX requires the mains to be disconnected if you use a PS!

Phil

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Phil - in the case of the NDX, the XPS or 555PS provides all the power and also the chassis earth connection via the Burndy. With the Naim DAC, an external PS upgrade still requires the use of the internal PS (which still powers the DSP section) so mains earth is still via the mains connection on the DAC rather than via the Burndy from the external PS. I’m presuming here that the ground lift switch is just a switch rather than a switch controlling a relay but i’m not 100% sure. Relays (reed relays) tend to be used for the RCA / DIN switching.

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