Grounding issue - Nait 5si & Trichord Dino Mk3

The most recent version, released in 2017 or 2018.

Do you use a Rega mm cartridge? If so there is the problem.

Id doubt the issue is with the dino. I used a mk3 and diablo with the ncpsu with now issues with both my Rega P25, P6 and Gyro SE. I used one on top of the other with no issues. They are a good piece of kit.

Ah ok - they’re double insulated so no mains earth connection at all with that amp.

Running out of ideas here but just to recap -

With just the Dino and Nait connected (no sub and no TT) you still get a residual hum.

Is that just on the input the Dino is connected to ?

One more thing I’d suggest is taking a wire from the earth terminal on the Dino and connecting that to the outer ring of a spare RCA socket on the Nait. What does that do to the hum ?

To recap:

With just the Dino and Nait connected (no sub and no TT) you still get a residual hum.

That is correct. Regardless of whether the TT is connected a hum is there. Can barely hear at normal listening levels, but when you really crank the volume (say, past 12 o’clock) the loudness of the hum increases proportionally.

Is that just on the input the Dino is connected to ?

Yes. Have tried multiple inputs on the Nait 5si, RCA and DIN. Whichever the Dino is connected to it doesn’t seem to matter.

One more thing I’d suggest is taking a wire from the earth terminal on the Dino and connecting that to the outer ring of a spare RCA socket on the Nait. What does that do to the hum ?

Tried that last night. No change, hum still around. I emailed Naim support to see if they had any bright ideas, along with Trichord again. Worth emailing Rega direct?

Sorry I meant, if the Dino is connected to Tuner for example and you switch input to HDD and leave the Dino on the Tuner input, do you hear the hum on the HDD input or only the one the Dino is connected to ?

Ah, gotcha. It’s only on the input to which the Dino is connected. I have it connected to the Tuner DIN input as standard, when switching to the other inputs, no hum - quiet as a mouse :wink:

Ok that’s interesting. It looks like you’ve tried most things to eliminate this but as it’s only occurring on the input the Dino is connected to, regardless of whether the Rega is plugged in or not - the problem lies on this path.

I’m wondering if there is some incompatibility between the 5Si inputs and the Dino output. The 5Si is effectively a power amp with a passive volume control in front of it so the inputs aren’t buffered. Might be worth mentioning that to Trichord to see what they say.

1 Like

Agree with your assessment after all this troubleshooting. Thanks again @james_n ! Will mention to Trichord as you suggest. Let’s see if anything comes of this.

I’ll be very interested in the fix, so I hope you manage to get some guidance from Trichord and Naim support.

So, Naim and Trichord responded with the same idea. They suggested using 2 wires to the earth pin of a mains plug, wire 1 connected to the grounding terminal of the Dino, wire 2 connected to the outer casing of an unused RCA input on the Nait. :man_shrugging: That seems to have sorted it.

3 Likes

Yes, that makes sense. Glad you got it sorted !

1 Like

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.