Loosing one channel, again!

Years back when I had my NAP300DR, I suddenly lost one channel (left), it ended up being a faulty relay and Naim replaced the amp with a new one… Since then I upgrade to the NAP500DR which has been working trouble-free since I bought it.

A few days ago I sat down for a listen and noticed that my left channel volume was very low and distorted, I could only resolve it after powering down my stack and powering back up, then the problem disappeared.

Today I went back for a quick listen, and to my surprise the same problem, when the music started the right channel appeared to be working while the left channel volume was very low, and full of static distortion sound. I turned my NAP off then back on without turning down the entire stack and the problem went away… but during my listening, about 30 minutes later suddenly the left channel started distorting again and dropped the volume on that channel…

Not sure what could be going on here… any hints? The problem is not identical to the old one I used to have with the NAP300 since back then the left channel was completely dead, no volume at all… this time the behavior is not identical…

This sounds rather like what happened with my 250DR a couple of years ago. Perhaps @NeilS can give some idea. However, it does sound like its needs some attention, so a good idea to get in touch with your Naim dealer.

Thanks Richard, I was thinking what was new or what changed in my system before I first noticed this issue, and the only new thing was the introduction of the Shiit Audio Loki+ in the path between the Chord Save and my NAC500.

I now removed it from my rack to see if the problem reappears.

I will wait to hear any insight from Neil.


Which pre-amp are you using? Still the 552? Did you have the Loki in front of the pre-amp or between pre and power? Wondering whether something there may have caused the problem? Yes, probably best to wait on @NeilS

I am using the 552, and the Loki+ was between the Chord Dave and the 552 so not sure it can mess much with the electronics… Nevertheless I removed it… I have to say the sound quality jumped with it out of the way, even though I had the Loki+ on bypass mode…

Whats the point of putting a $149.00 EQ between a $10K Dave and a $25K 552 preamp this makes ZERO sense, zero. Lose the Loki and double check all your connections.

1 Like

Hi Richard/thijazi,

I’d like to be able to offer some insight here, but I can’t recall what was wrong with your 250!
It does sound like a power amp issue though, preamps with the dreaded relay faults would be all or nothing.
Definitely will need looking at, but the cause could be any number of things making remote diagnosis impossible I’m afraid.
If you have any means of narrowing the problem down to a particular unit via substitution, that’s always a bonus.


1 Like

The Loki+ was there for fun, just testing how it I could setup a few older records to play more to my liking, it was there for fun… Its not in the rack now, will give the system a few weeks of time to see if the problem reappears without the Loki…

1 Like

Since I reside in the UAE it is pretty hard to have the NAP sent back, I will test this some more and monitor how it goes, if the problem creeps up on me again, then I will have no choice but to pack the NAP up and send it back to Naim for testing…

Does your preamp have a separate tape loop?

I believe no, its the 552 and as far as I know there is not tape loop… why?

The NAC552 has three tape loops.

I see the Loki is a tone control device. In which case you should insert it through a tape loop. That way you can switch it in or out of circuit easily.

1 Like

What He said

Interesting, I was basing my assumption on the following article which states no tape loop as such… I can see in the manual a tape input (Input 4), what would that do that is different? The Loki+ has a bypass switch which essentially stops it from messing with the tone…

Which article would that be?

The manual clearly shows that inputs 4, 5, and 6 have signal in/outs (tape loops).

The Loki may have a bypass switch but I doubt it’s totally transparent even when in bypass mode, as signal would still have to route through it. When it’s connected via the tape loop, you can completely remove it from the circuit if you choose.

I’m a bit surprised your Schit dealer didn’t show you this or talk you through how to best use the device in your system.

This one here: Naim NAC 552 preamplifier | Stereophile.com

Thanks. Obviously an error on the reviewers part.

Didn’t have the luxury of a local dealer for Schiit, ended up buying it online, it is mainly being used for my headphone desktop setup, I wanted to see how it would sound on the full system and had it installed for a few weeks on the Naim gear, but since taking it out the system sounds miles better even when it was in bypass mode, so something was not right…

I never thought of the tape loop option, however not sure how it would remove it completely out of the signal path, I have the Chord Dave via RCA connected to the Loki then the Loki to the 552 via another set of DIN-2-RCA connectors, I would not have the ability to take any other unbalanced output from the Dave out to the NAC as long as the Loki was in the middle… am I missing something?

Thanks for your help here Richard.

I suppose one cannot really use the XLR outputs on the Dave with the NAC.

To insert it into the tape loop you just need a tape i/c (DIN5 with 4 x RCA Phono). You would then use the tape loop a bit like you would the monitoring of a tape deck, allowing you to switch the Loki in or out depending on whether you like what it does or not. Once switched out it has no effect on the signal chain as it’s completely bypassed.