Pop through speakers when powering on or switching to source - Nait 5si & Cambridge Audio 851N

Hello! I am hoping for some advice regarding an issue I am having with my kit.

My setup is a Nait 5si driving Q Acoustics Concept 40s with a Cambridge Audio 851N as source.

Recently (in the past month) I have started getting a pop through one channel when the 851N turns on or when I switch the amplifier source to or from the 851N. This always occurs on the side connected to the right channel of the 851N. The pop changes volume with the amplifier volume and is irrespective of which input is used. It is heard with both RCA and DIN connections, though is quieter via DIN. Some interference noise can also be heard when changing the volume. The 851N has digital pre-amp and direct modes, the same issue occurs in both modes. If both the amp and 851N are disconnected from power and reconnected the pop only returns after a few hours or an indeterminate number of standby cycles on the 851N.

All other tested sources are clean therefore I suspect the problem lies with the 851N and not the amp (especially as it changes with amplifier volume level). I would be interested if anyone else has had similar issues with their equipment and had theories as to a cause or solution.

Obviously turning down the volume on the amp before powering up the 851N or changing source is one solution, but this is easily forgotten plus is hiding the problem, not solving it.

I have an Azur851n running into the cd input on my 52.
Normally, I leave the “mute” button on, but last night I switched the 851n on without mute being engaged, and there was no noise.

If your amp has a mute switch I would leave it on until the Azur has stabilised. If the Azur has a fault it is one of those which will probably not be resolved until or unless it changes into something worse.

Is it under warranty, or did you get the extended warranty from, I presume, Richer Sounds?

Thanks for the reply!

Mute or volume on minimum on the amp before powering up the 851N works in terms of avoiding the pop, but that relies on me remembering to do it…

I agree it’s one off those faults that’s going to be difficult to resolve. Unfortunately I have no warranty, it was purchased second hand around three years ago. Richer Sounds advised contacting Cambridge Audio direct so waiting for a reply from them.

It won’t solve the problem when changing source but to avoid the switch-on pop, why not leave the 851N powered up 24/7? I assume the Nait is left on as that is standard recommendation for Naim boxes (with usual caveats) as is the powering-up sequence: sources first then amplifiers.


It is good practice to drop volume control to zero before changing sources (switching or unplugging/plugging), ditto turning on/off a powered electronic source, whether CD player, streamer or head amp etc. And if powering off or unplugging preamp from power amp, always turn off the power amp first (and turn it on last).

Following good practice avoids annoying pops etc - and more importantly avoids the otherwise potential speaker damage if a very loud pop.

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