Earth Loop Hum

And for the record, I've known my dealer for nearly 30 years and he's superb.

Hi Bryce,

As, after disconnecting the phono cable from the A/V system at the 552 end and swapping the 552 (& 552PS) and 555 (& 555PS) you still have a hum problem, then that strongly throws suspicion on the NAP 300 or NAP 300PS.

Update - dealer was out on Thursday and tried various things with power leads, SNAIC, interconnects including DIN - XLR without success.  He's since had several phone calls with hopefully clever people at Naim.  They suggested that the transport screws might have damaged some wiring which sounds rather like a design flaw to me!  Yesterday he was back and substituted a Moon CD player for the CD555 using existing power and IC leads.  No hum.

We've both lost track of what we've previously tried but he definitely tried a different CD555 at one point and we both thought different 555PS and brundies too so slightly confusing but feels like progress.  He is taking my CD555, 555PS and brundies back to the shop to try on a different Naim system.  Assuming the player is going back to Naim for repair I can get it serviced at the same time.  Over ten years old.

Fingers crossed and vvery grateful for all the help on the forum.

Good news Bryce. Sounds like it's moving in the right direction. Let us know the outcome when you've got it all sorted. 

Cheers

James

Bryce Curdy posted:

...  Assuming the player is going back to Naim for repair I can get it serviced at the same time.  Over ten years old.

...

That may be the reason, capacitors can go out of spec with time.

Usually they do it slowly but occasionally you get one that deteriorates faster than usual.  It's rare but it does happen and there's no way to know when the unit is built at the factory.  There's no way to test for the ones that will go out of spec sooner, it's purely random.

Bryce, 

Any news?

Dealer says he could reproduce hum (but not as loud) with a non-Naim amp in the shop.  I'm assuming this was a quicker and easier diagnostic than using a Naim amp and it wasn't the case that he couldn't reproduce with a Naim amp, but I should have asked this specific question when I spoke to him.  In any case, the CD555, 555PS and brundies are being returned to Naim.

UPDATE

Very, very disappointed at Naim.

CD555 and 555PS serviced and updated including (I think) 3 capacitors exchanged.  Naim were unable to replicate the humming problem,  I am just off the phone with my dealer who has not long plugged it into a 552 owned by a member of staff and the problem is very obvious.

Slightly off topic but having ordered the first Uniti Atom sold by my dealer I resisted the temptation to pass comment on the fiasco of the launch.  I have been a loyal Naim customer for nearly 25 years and feel extremely let down and unimpressed with both of my recent experiences.

In the event anyone from Naim reads this I would be grateful for some prioritisation. 

Bryce Curdy posted:

 

In the event anyone from Naim reads this I would be grateful for some prioritisation. 

Understand your frustration ... but I don't think your comments here are likely to reach the right people at Naim as a matter of priority!