Has a power cut sent my 300 PS into a frenzy?

Last Saturday evening at around 23:00 we had an unexpected power cut. I waited until midnight then went to bed with the power still off. At 01:30 the power came back on again.

There has always been a slight hum from the 300 PS, but nothing like some people report.
However, since the power outage the hum is now very loud.
Is this just a coincidence or has the power outage done something more sinister?
When the power was restored the Naim system came back on as if nothing had happened.
I would have thought the power cut would have necessitated a manual twitch on? :thinking:

Has anyone had a similar experience?

Hi David, I’m not surprised that it all came back up. They’re not soft switches.

It could just be a temporary issue with the local mains supply as you had a reasonably long power cut. Maybe a temporary repair by the Power company to get the power restored has changed something.

I’d leave it a couple of days and see if things improve but in the meantime you could just power the system down, make sure all mains cables are nice and secure and then power it back up again (300PS last) and see how it goes.


Could also perhaps be something else on the mains ring has been affected by the power cut, if you don’t have a dedicated source for your system.

It might be worth checking by switching other things off in sequence to see if that reduces or removes the hum.

Our Sky box has been the culprit in the past.

Worth a try if you have a spare few minutes.

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We had a 5-day power cut after storm Arwen - it took days before the mains stabilised and for the ensuing hum to stop

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In another thread I mentioned one property I know which was off the grid for two months after Storm Arwen, although the electricity company did give him a big diesel generator after the first few days. These repairs can take a long time.


If there has been a power cut the first thing I do is power the Naim kit off. Only when the power has returned and been on for say 1 hour do I power the Naim kit in the correct sequence.


…and the Meridian DSP 5.1 system, and the TV, and the computers and the network, etc

Inrush currents can be very entertaining at “knife on” main power (re)connection :slight_smile:


Thanks James, I’ll give that a try. :+1:


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Thanks @Guinnless

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Thanks…Have loads of building work done at the moment, then a re wire.
Will have a new 10mm dedicated supply for sure. Will also look at DC blocker.

Just a thought, but sometimes you may find that the electricity supplier bypass the local substation, and feed you from a different station (or leg as I think they call it). This may be temporary while they carry out repairs/upgrades on the substation.

It might be interesting if you could measure the voltage you are getting to see if its particularly high?

I live in the North East of the US. At this time of the year we have so many thunder and lightning storms my system has been off for weeks. It sucks! It usually takes a day or so for the system to really come on song but with the storms better to keep it off. Of course I’ve been listening to my Muso II much more :grin:

In a power outage, or was it, I came down one morning to find all the Naim kit on my dedicated mains spur had tripped the circuit breaker. The rest of the supply to the house was OK.
In a moment of definatly not thinking I went to the garage and pushed the breaker back in. There was a flash and a bang from the unit which sent bad thoughts to my brain. Back to the system and all OK.
My dealer wasn’t surprised bearing in mind the number of power supplies I have including a 500DR. He said current Naim units are a lot more robust these days.
Still makes you wonder the potential damage if this happens when you are out of the house or in bed overnight.

My system has always started up fine after an unexpected power cut too. (Unlike lightning strikes :scream:) I guess it’s no surprise that the breaker tripped given the inrush current from all those boxed at the same time, especially if you have a standard Type B breaker, although even a Type C might struggle.

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