My MF nu vista 300 power amp can run hot. Especially if used in a confident manner. I do use a small usb power fan to keep the case cool.
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Its been a lot of years since I had a 250 but I never got the 52 above 10 on the dial for cd, might want to be careful when half cut lol.
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Going past 11 O’clock must have been loud.
Pete Tong would sound better with a blown fuse.
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I run my 250DR hard at times and never had a fuse blow. In fact, I’ve run all my 250s hard over the years and never had a fuse blow. Maybe your mains aren’t up to snuff.
It wasn’t the fuse. It was just the thermal trip protection cutting in when the amp got too hot.
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I’ve never had my 552 or any Naim preamp more 9:30
Something sounds fishy if u have your volume at or past 12:00 with CD player
David
Don’t think I’ve ever had my 250 past 10.30, think Mrs Pete would clip me long before I got anywhere near 12.00.
I’ve had 3 Naim power amps and never had them shutdown.
At 85dB efficiency your speakers are rather power hungry to pump high dBs, you would probably need more power if you intend to do that more often, and I don’t mean 10 more watts…
If it’s not distorting the power is enough, just about anyway, it’s the heat dissipation that’s lacking and a 300 has a fan for just this eventuality so another 10W might be enough. Alternatively an external fan blowing across the 250’s case could do the job for a lot less money.
If you’re going to listen to music that loud then get a 300DR. The fans will cut in avoiding a thermal trip. I had a 250 CB and playing it at prolonged loud volumes it would trip out. So I got the 135s with fans and have no such problems!
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I can’t imagine that the output transistors (amongst other components) will stay healthy for long with repeatedly grilling them…i had a friend who used to regularly cook his amps (admittedly not Naim amps) blasting out ACDC, then after about two or three years he would take the lid off to have a look, what a state. Everything inside would turn brown, even the underside of the lid would look like a George Forman grill 
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Running stuff hot is one thing, keeping it cool is the key. And yes, stuff will last longer if it’s kept cooler.
I suspect the OP cranked it up, with him fuelled with ale, and was fortunate that the 250s protection saved itself. No fuse failure was involved.
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Same here. Small mains fan works a treat, and obviously you can’t hear it over the music.
At those levels you couldn’t even hear a large one.
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Maybe before going down a 300 route, which is two additional boxes instead of one with a 250, it would make sense to see what the options of active ATC is. Maybe it is too late and not so straightforward going from a passive ATC to active? For sure the advantage of active ATC would be to lose a box. It would be interesting to hear from the more experienced ATC users on here regarding those possibilities
Or maybe a Disco system would be more appropriate?
This thread reminds me of Robin Williams in Good Morning Vietnam when the artillery gunner sergeant called in to request a tune along the lines of it didn’t matter what the tune was, just make sure it’s LOUD!!! The other little snippet from the sound track album in part describes the OP’s 250 stuck at 12 noon on the dial - Hot I say, Hotter than a snake’s ass in a wagon rut!
Peter
Yes. Strange to me to have those sorts of listening levels 
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I find 9 o’clock is normally plenty loud enough or maybe 10 o’clock on vinyl. At 12 o’clock looking at wild distortion and fear of amp and speakers blowing up!!
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