Overheating NAP250DR

Good Evening All,

As a Naim user of almost 35yrs I have known about the NAP250 ‘shortcoming’ since I acquired my first set of Isobariks. I have always found it frustrating that even using 3off NAP250 when driving Isobariks actively this overheating problem is still there.

Having to buy 6off NAP135’s to ‘solve’ the problem may suit Naim but it is an expensive option for the end user.



Mike - the Chord & bananas isn’t optimal (better NACA5 and use of Naim’s plugs at amp end) but…not something to fuss on.

You should be able to use as you outline, noting the protection of the thermal trip (n.b. this is also offering protection to the speakers). BUT…I think 12 noon is pushing a 250 and the system a tad and would suggest some moderation if poss.

Another solution I’ve heard of would be to put a bowl of some ice (not full) on the casework, with a towel underneath - obviously this cannot be recommended!

That will depend on the recording level of the music being played, output level of the source, The impedance of the speakers, the speaker sensitivity, the distance between speaker and listener, and also on the characteristics of the room.

(The SCM 19 is nominally 8 ohm, so not abnormal.
Its sensitivity is 85dB/W @ 1m - a bit lower than many.
3.2m distance from speaker is a bit further than average, based on a recent poll on the forum.)

But of course some music sounds best loud (actually I think most music sounds best at “realistic” levels… ).

[Edit: I originally mistakenly put SCM 40 - corrected to 19, other info unaffected as they are the same nominal impedance and sensitivity.]

By “realistic” do you mean live gig levels? No problem in my 20s and 30s, but nowadays anything above 50 (on a 272 - don’t know what that equates to on a 282 volume control) is a bit painful for extended listening sessions.

OK. It’s now moot. I’m backing off the volume…

We’ve had some stranded Manxians next door (shared space) during Spanish lockdown and I’ve been entertaining with some “over-the-wall” sounds, periodically, via my open windows.

Well - they’re going home now so it’s back to normal volume levels.

Thanks all for the advice and info. Now for some moderated Charlie and Antonio…


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Well, I never made it to full blown active with Naim. But here’s my over-heating experience with Naim’s legendary 250.2.

Remember, there’s a lot crammed into a single black box, unlike the 300.

I been running a pair of late model Briks for nearly four decades. Not the Domestic Monitor Speaker (DMS), nor the Professional Monitor Speaker (PMS). The former were ran passively, and the latter was designed to be ran actively.

My Isobariks have been ran with a single LK 280, and Bi-amped with an addition of an Spark. Finally I went full blown Active:

LP 12/Gengki > Karin > Linn crossover with bingo card, Dirack PS powered by 3 LK 280s. {{In all those years, no humming amps, and no over heating!}}

With that being said, I still prefer Naim Amps. If I had to describe my experience with Naim’s regulated 250.2 the two adjectives would be thick and rich accompanied with the clarity and accuracy of the Nac 282.

Just lovely, to say the least!


Bi-amped Briks with 200 on the tweeters and 250 on the mid range and woofers. Entertaining @ 10 o’clock for more than 40 minutes, the 250 would shut down. Invested in two small battery fans.

Decided two switch the duties of the amps, and put the regulated 250 solely on the tweeters, and let the non-regulated 200 handled the mid range and the woofers.

No shut downs!!!

Mr. Richard Dane explained the 250 being an regulated amp it wouldn’t slip on the job and shut down.

To be honest, I couldn’t tell the difference when I switched the amps duties.

In any event, I decided to tri-amp the Briks with the addition of another 250.2. No fans, or shut downs but I rarely pushed them beyond 10.5 o’clock for more than 15 minutes.

When my neighbors walk by house they thought it was a live band!

Enjoy your music.

The Why!


Mike use ATC 19. It should not be a problem. Of course some recordings are very low recorded, but even that I have never went more than 10/11 o’clock.
Most users go generally at 9/10 o’clock.
As someone reported, it may be a speaker cable problem or non match.

I have no issues with my NAP 250 DR and the Chord Epic Twin cables …

So I don’t understand what is the problem, because 250 and ATC 19 should not give the need to be always at 12 o’clock. Or maybe a bit of hearing loss could explain eventually.

I refer the Hon Member to the reply I gave earlier. :roll_eyes:

I had a CB 250 and was playing the music at loud volumes and it did shut down on a fair few occasions.

I swapped it over for pair of 135s. The cooling fans kick in quite a bit and it has solved the problem. And it sounds better!

Interesting, I have the same amp and have never managed to shut it down. Usually I listen at 9 to 10 o’clock. 12 is very loud and although I like to rock occasionally a couple of hours at that volume would be painful. That said I’m not sure I get why an amp would have a volume that goes all the way round if it can’t be used past 12 o’clock safely.

I think this has been explained earlier on in the thread. If you are using a phonostage with low output cartridges then you need to turn the volume higher to compensate. I don’t turn the volume much past 9 o’clock and I like music loud!

The point I was trying to make is that setting on the volume control does not equate to a given loudness unless all the other factors I mentioned are identical. And of course different people like different loudness levels - and different music suits or demands differnt loudness!

Live classical concert levels certainly. Rock music occasionally gig levels, but when I do only a limited period out of respect for my ears, so a bit less. A typical listening level for me is around 85dB(A) average at my head position, but peaks of course are higher, sometimes a lot higher, depending on the music. The 24-bit Telarc recording of Tchaikovsky’s 1812 needs playing quieter than that, otherwise the canons push the amp into overload (with 500VA on tap)!

I can barely get the volume over 9 and things get too loud.

Me too, some days I play music at set around 9-10 all day and so far my 250 hasn’t shut its self down once. I have a reasonable sized room that often gets quite hot. 12 is very loud I’d probably throw the towel in before the amp.

I had the same issue with my previous 250, I tried many tricks but it did not really help including freezing my room down to 16 deg C, my friends used to joke saying I have such a nice system but always trip half way through the party, the solution I went for was upgrading the amp to 300 and the problem disappeared. I usually play between 9 and 10, and when I have friends over, I do play a couple of hours on 12. So if your 250 cannot handle it, it might be that your speakers are speaking to you begging you for more power :slight_smile:

To be available in July, the Statement , which comprises the NAC S1 line preamplifier and two NAP S1 power amplifiers , will be priced at $200,000 and is specified as delivering one horsepower (740W) into 8 ohms!


Naim’s reference amp @ a whopping (140 W) into 8 ohms:


Naim’s reference power amplifier, sitting above NAP 250 DR and NAP 300 DR and delivering performance that far exceeds both.

What about it.