Dead NAC552 right channel

Posted by: thijazi on 01 July 2017

Seeking the opinions of a wider group, maybe I am missing something obvious here... (this is something that started as a another thread at: https://forums.naimaudio.com/to...chord-dave-vs-dac-v1)

I have been on Naim gear for a few years now, and my journey started from NAC202/NAP200 all the way up to the current NAC552/NAP300 setup. I listen only to digital (all music in lossless FLAC, High-Res or DSD formats). For a few years my source was a Naim DAC-V1 unit which after a few years got replaced in February this year with a Chord Dave which elevated the sound qaulity quite a bit.

A couple of months after introducing the Chord Dave to my setup my NAC552 suddenly decided not to output anything on the right channel, I tried everything I could think off to trouble shoort this, my local dealer (who have been super-helpful and good) tried everything they could think off and in the end deemed that the NAC552 although brand new (had it for less than a year) had to go back to the UK (I live in Dubai) for servicing.

A month later, the NAC552 is back, I have been listening to it back into my rack for the last few days extensively with a lot of joy (the sound is as you would expect stellar)... However today the same thing happened, suddenly I have no output on the right channel, exact same behaviour like the last time I had this issue.

Now having the same issue reappear a few days after the unit came back from Naim service is unusual, I am looking for opinions on what could be wrong here. I am very particular about my setup and don't cut corners, just to give you a description I have the following setup

Chord Dave (brand new) hooked via an AudioQuest Carbon USB cable to an mini-PC as the digital source
Chord Dave is hooked up to the NAC using a Chord Crimson VEE 3 Din-to-dual RCA cable from The Chord Company
The NAC552 and NAP300 are interconnected using Naim cables, with SuperLumina XLR (for 552PS to NAP300) and I also use SuperLumina Speaker cables for my Sonus Faber speakers.
All the power leads are Naim Powerline cables (including the Chord Dave!)
I have a small power-strip from the Mains-Cables-R-Us store in the UK (Hi-Fi grade power extension chord).
The gear sits on a Naim Fraim, no other electronic equipment in the same room.

This very well may be a faulty NAC552 period, if this was related to electricity surely it would not always affect the right channel only? I would have seen other symptoms. I am not sure if the Chord Dave has anything to do with, or the Chord Crimson VEE 3 cable (I replaced this with a standard RCA cable with the same result).

Any idea? anyone seen this type of thing? Below are all the steps I took to try an isolate/troubleshoot this issue:

To rule out the speaker cables/speaker I swapped the cables around and
I could hear the right speaker working fine. Therefore nothing wrong with
the cables or speaker.
To ensure the problem is not due to the Chord-VEE3 DIN-to-RCA cable
(Which I use to connect the Chord Dave to the NAC552) I replaced that cable
with an audioquest RCA interconnect, it did not fix the issue. Therefore the
problem is not in the Chord-VEE3 DIN-to-RCA interconnect.
To rule out the SuperLumina DIN-to-XLR cables, I swapped them for the
stock cables that shipped with my NAC/NAP and the same issue remained.
I replaced the Naim DIN interconnect connecting the NAC552 to the
NAC552PS with an identical one I had from a previous system. Same result.
I tested once again with the Chord connected straight to the NAP300
via XLR and it works fine, both channels sound fine. This leads me to
believe that the NAP300/NAP300PS is ok, both channels work fine when fed by
any other preamp
I reset the NAC552 to default settings using the Narcom remote, same
result.
I reset the Chord Dave to factory settings, same result
I replaced the Powerline cables with stock power cables to rule out
any electronic interference due to power, it did not help.
I checked all the Burndy and DIN cables to see if any pins where bent,
etc. nothing detected.
I literally took the system completely apart twice, completely
disconnected every connector and every cable, and reconnected everything,
started up and same result... Sound only on one channel.

This is one expensive Pre-amp so needless to say I am disappointed that i am getting a recurring issue now,...

Thanks for any feedback, insight you may share... Keen to troubleshoot the cause.

Take care

Posted on: 05 July 2017 by james n

thijazi posted:

I have lost confidence in the particular unit I purchased from Naim, I feel like this issue and potentially other issues lurking around will only happen again and again.
If I was living in the UK I would cope with it better, but spending 2 month each time waiting for my unit to ship to UK and back is silly given the amount of investment I made to have the best experience...

Understood. Probably best to take this up with Naim and your dealer directly to come to an appropriate solution. Threads like this normally just end up with a lot of unnecessary noise which doesn't end up solving the problem.

Hope you get it sorted and report back the resolution.

James

Posted on: 05 July 2017 by analogmusic

thijazi posted:
Another thing that I often think about is the choice of connection between the Chord Dave and the Nac552, today I am using an RCA-2-DIN cable, I could also use the standard RCA interconnect.
I am using the RCA-2-DIN cable due to a belief that Naim is basically better suited for DIN connections and that may have a better sound quality..
Could the issue be attributed to the choice of interconnects?

I doubt very much that your interconnect caused your 552 to fail eek

Some of the recent very high performance RCA tp RCA interconnects from Vertere can beat lesser RCA to DIN interconnects, but that is another story.

Vertere Pulse B does cost a lot of money though, 1000 GBP, but fantastic performance in terms of clarity and preserving the musical energy.

(yes I am a vertere fan)

Posted on: 13 August 2017 by thijazi

Well, it took a while but you have to hand it to Naim folks, they replaced the NAC552 with a brand new one without a hint of hesitation, got my new unit delivered and setup yesterday, so far so good.. Fingers crossed the gremlins don't come back, I even replaced the interconnects to ensure all is well in that department....