Naim Nait 5i Hum

Hi, I am new to this Forum and just after a bit of advice please. I have recently acquired a second hand Naim Nate 5i integrated amp to upgrade my old (and relatively cheap) Cambridge Audio amp. I use 3 inputs to the amp. The main one I use is my Pro-Ject Debut Carbon turntable through a Rega Fono Mini. For convenience I have a Chromecast Audio. I also have a cheap DAC converter to connect the Optical output from the TV. All of this worked fine with the Cambridge Audio amp into my cheap and cheerful Cambridge Audio Sirocco s30 speakers (which will be upgraded next).
The problem I have now is that the Chromecast is fine when it is connected i.e. the amp is silent with zero hum. However as soon as I connect either the Turntable or the DAC, I have a relatively loud hum on all of the channels.
After a bit of digging on other forums, the key points seems to be the following (quoted from a couple of sources):
“Naim amplifiers have a double earth system. In order to prevent hum, you need to put in a link wire from the source casing to the amplifier casing. This effected a 100% cure.”

“Taking a length of wire from the chassis to the middle pin of an unused DIN socket silenced the nonsense. I have, for the last couple of months, been enjoying my music once again.”

So just to be clear, I need to attach a wire (any wire?) to the middle pin of one of the DIN sockets (how would this attach?) and then attach it (solder it?) to where exactly?
I have zero knowledge or expertise with electrics so any advice would be greatly appreciated!

First, I take it that the hum is coming from the speakers.
If this is the case, it sounds as though the signal isn’t grounded anywhere or possibly you have an ‘earth loop’ (i.e. the signal 0V line is connected to earth at more than one point).

As far as I can tell, neither the Project nor the Rega phono amp are grounded, expecting the amp to do that. However Naim amps expect one of the source components to be grounded (as that gives a better hum response with an appropriately designed source component).

There is an earth connection on the Rega, and connecting this to the mains earth (use single core wire [any type, doesn’t matter] to the earth pin in a 13A plug with no connection to the line or neutral pins) should sort the issue.

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Thanks for the reply Xanthe. At the moment I have the earth cable from the turntable connected to the earth connection on the Rega phono amp. So just to be clear, I should now connect a wire from the phono amp to the mains earth as you describe (presumable whilst still leaving the Turntable connected to the Rega earth?).



Sorry to barge in on this thread, but I have a similar issue with my Rega Planar 6 (c/w Rega Neo power supply). I have a Naim Uniti Star with an Arcam rPhono.

The Arcam rPhono manual states

Neither Rega box has a ground connection; the rPhono does, but it is not connected. Should I run a thin wire from this to a 13A earth pin in the wall instead?


Do you have anything else connected other than the Arcam rPhono?

If not…

First make sure that the ‘Ground’ switch if the star is in the ‘Default’ position (i.e. not set to ‘Floating’).

Then ensure that you’re not causing a second earth connection through the Ethernet cable.

By the way Xanthe, I did exactly as you described above and it worked a treat - thanks so much!

Excellent, thank you.

@Xanthe Thanks for that; the only components I have are the Uniti Star, Rega Neo & P6 and Arcam rPhono. No ethernet cables are used. The Star’s Ground switch is set to Default (not Floating), but when I wire up a 13A plug with just an earth wire & connect that to the GND terminal on the rPhono, when the turntable input on the Star is selected the hum is (much) worse. So I have disconnected it for now. :flushed:

OK, try putting the earthing cable back in and setting the ‘Ground’ switch to ‘Floating’.

Having both the earthing cable in place and the ‘Ground’ switch at ‘Default’ will itself cause hum as that will give you an earth loop.

Changing from Default to Floating makes the hum go from “(much) worse” to “(slightly) worse” than if no ground wire connected to the rPhono at all. So maybe it is not a ground hum after all? That said, there is effectively zero hum when Internet Radio, external USB or TIDAL is selected … :thinking:

That there is no hum from the other inputs strongly suggests that it’s a problem with the
or TT
or phono amp
rather than the Star.

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