NAP 250.DR shutting down alone

Posted by: thijazi on 06 May 2016

I was testing a new setup (Hugo, thread at: https://forums.naimaudio.com/topic/dac-v1-vs-hugo) and spent 3 hours listening today at moderate volume level, then at the end of my listening session I cranked up the volume to listen to a couple of high energy tracks louder and then my NAP 250 turned off ... I touched it and it was way hotter than I ever felt it. The light was off, I turned the switch on and off and nothing helped. I let if rest for 15-20 minutes and tried switching it back on and then it worked.

I have spent much longer listening to music and many times much louder, and many times after a long listening session I would put my hand on the NAP and was always amazed how cool it was, never felt very hot (I had other amps in my system that occasionally felt super-hot). The NAP never did this before so I am wondering why would it over heat suddenly, same conditions, same room, same rack, same playback software/sources, same speakers, same speaker cables.

The only changes to my system are:

Last week upgraded the DAC-V1 to PowerLine, I upgraded to PowerLine on the NAP and NAC a few month back.
The fact that I hooked up a second PC (the Hugo I am testing is attached to this second PC) so that I can test the DAC-V1 and the Hugo side by side by simply switching the preamp input selector, the Hugo is connected to the NAC282 via DIN, can't see how that would affect the power amp at all

any suggestions?

Posted on: 07 May 2016 by analogmusic

I managed to make my 250 DR run quite hot, during my teenage daughter's birthday party, where a "professional DJ" was playing the songs, which had very heavy baselines, and at that time, the system was not signal earthed - the output was from a quite expensive professional Pioneer DJ machine, and the 250DR was driving my Dynaudios to very high volumes, but not once did the system shut down. The 250 DR did get very hot though, but I increased the air-conditioning in "dj room"

In the prior year, my NAP 200 was driving my B&W 805s to equally high volumes, but the NAP 200 didn't even break a sweat, it remained cool the whole party, and the B&W took the punishment like a champ, and the DJ said that was the best sounding system he had heard in his entire life. He didn't understand why I sold those fine speakers for Dynaudios.

One concerned parent asked me why I would risk my expensive Naim and B&W on a party and I just grinned, if the amp doesn't like the punishment, it will just shut down, but ... I am impressed it didn't.

I really think sometime else (and not the Hugo) is going on for a 250 or 200 to shut down in a domestic situation, because your ears should give up well before the amp does.

My uneducated guess (as I am not an engineer) is that the domestic supply is not able to cope with the demands made by the amp, (maybe the copper wiring in the home isn't up to it) rather than any issue with the amp.

Posted on: 07 May 2016 by Noogle

When I had a 250 driving Ovator S400s it used to overheat and shut down after a while of playing at "party" volume levels - but that was pretty damn loud - say midnight to 2pm on the 282 volume control...

Posted on: 07 May 2016 by MDS

Noogle posted:
When I had a 250 driving Ovator S400s it used to overheat and shut down after a while of playing at "party" volume levels - but that was pretty damn loud - say midnight to 2pm on the 282 volume control...

Blimey! That's pushing it, Noogle

Posted on: 07 May 2016 by Chris Dolan

Sounds about right