How reliable is Nap500dr

Hi just wondering … how reliable is this complex amplifier…I leave mine powered 24/7…what are others experiences???

Stop it…….you started me worrying now.


What would cause it to fail?

Would it reassure you guys if I said, since the 500’s introduction (22 years ago?) - if I were to count the amount of genuine fault repairs I’ve personally undertaken on my digits, I probably wouldn’t need to take my socks off?
They are pretty bulletproof.



Well it has 4 amplifiers linked together with some tricksy circuitry…and tweaked…and optomised. So stability is a worry in the back corner of my mind… just wondered what others experiences were… I would imagine if one transistor went down … the whole bridged amp on one channel would go splat…

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Phew…thanks that is re-assuring!!!

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Operating experience via @NeilS is key here. Good design builds in reliability. Apart from just working, it needs to just work. And keep working until ( just ) before its service is due.

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Imagine the level of paranoia you must be instilling in the minds of NAP S1 users :crazy_face:


Indeed — just have a drink and listen to your music. No point in pointless worrying; life is surely too short…

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Indeed. 24x7 for some twenty years with an interrupt to get them DR when that came out with my three.

One mains button latch failed once and needed replacement by Dealer that took 30 mins.

Naim say it is the cycle on-off that will cause more problems over time than just leaving them running, due to the on-surge current.

Mine get turned-off if a thunderbolt is likely within a mile of the house - and every few months they like a quick off-on when it seems a spike in mains has upset something, that is cleared by a mains reset.



Statistically nearly all electronic devices are 10x more likely to develop a fault at power on than spontaneously during operation.

Continued power on almost certainly increases the longevity rather than shortens it.

Of course 10x more likely to fail is not the same as saying it is likely to fail. Many users power off Naim power amps when not in use and never experienced a problem in years/decades.


AV (primarily TV) running through suitably serviced 552DR-ed (c.2005)/500DR-ed (c.2007) powered 24/7 for many years and never an issue, aside from a lightning strike nearby which necessitated a power-down/up of the 552.

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Actually, I think its 8… :astonished:

There are 4 amps (2 per channel), in a bridged arrangement - and each of those amps has a regulated power supply, which is effectively another amp… :face_with_spiral_eyes:


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Mine developed a fault about 6 months after I had it DR’d and serviced. It went back to Naim on more than one occasion and had the boffins at Naim well and truly scratching their heads. They ended up tearing it down to nuts and bolts and completely rebuilding it. Rumour has it the guy that builds the Statements was let lose on it. JG was great and kept me constantly informed of what was going on. I’m told I now own the most worked on 500 Naim has ever produced!

It does have a happy ending though, I got the call from JG saying that he was in the dem room listening to my amp and that it was truly spectacular. JG even asked my dealer to take a listen to it when they got it and they were blown away by how good it sounded.

All I can say, when I turned it on for the first time, was wow, wow, wow!

It is just sublime.


I can confirm that those 500DRs are usually sturdy pieces of kit, and about as failsafe as other decent electronics.

Our first 500 was among the first units built in 2001 (IIRC) and is running continuously without problems ever since. There has only been a downtime for the DR upgrade and the mains button quirk which was easy to fix.

The second 500 has been running for 15 years. End of last year, a rectifier in the PS broke. That is a rather uncommon failure of an electrical part but not caused by amplifier design. Unfortunately, I requested not only the repair but also an DR upgrade. Despite the demise of the upgrade programme a little later, this unit is still supposed to be converted. Right now, the amplifier is sitting somewhere and my dealer has a hard time finding out where it currently is, and when it will be converted. So, it has not been running for nine months and that is all pretty upsetting. No happy ending yet.

Good lord, have you been waiting nine months for your amp to be serviced and converted? That’s as long as it takes to conceive and give birth to a human!!

Something wrong, surely? I’d be tearing my hair out with frustration, if it were me.

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Life is full of ironies like this. When I was Hd HR in a major government business unit some one came up with a new recruitment process to ensure fair and open competition and to help ensure we met our diversity targets. When we worked through the proposal it became obvious that it could take 4 months to recruit someone to cut the grass at a RAF station. I pointed out that it only took 3 months to assemble a task force sail to the South Atlantic and reclaim the Falklands!


I’m hoping that you have at least been provided with a temporary power amp whilst the hunt for parts is (hopefully) being undertaken? Unbelievable time period - no wonder you ain’t happy.


That makes me feel very special knowing I am one of a very small number of people who’s amp failed. A nice guy called PB repaired my 500DR for me.

I must say it sounds fantastic now, thank you.