View Full Version : Busted Accuphase M-60 Monoblock.
Plugged in the Accuphase M-60s last night.
To be frank, I haven't run them since my DAC was upgraded. That's quite a few months ago.
So enamoured with how absolutely brilliant they were sounding with the newish DAC revisions (I never remember them sounding this good), I ran them for an extended period, probably three hours, quite regularly seeing the power output entering the 0.5 Kilowatt zone.
At 11:15 the wife came in saying 'turn it down', so I did. Both amps still running at this point.
Then I went out to make a cup of tea, came back in and one no worky. No smells. But the chassis were ridiculously hot in both.
Amp in question just doesn't switch on this morning. It isn't the plug fuse. I had hoped some sort of thermal protection had kicked in.
Any offers for the most likely cause of damage?
Wife says I had them turned to 11 and a half and they don't go to 11 and a half.
It was idiocy on my part. I am fully aware they get too hot at that volume for such an extended period. But the bottle of wine in me said 'nah it'll be alright':D
These amps are the first monoblocks Accuphase ever made (1975). They are worth something. I have no intention of selling them.
Panic over. There's a push in button at the back that had moved out on one of them. Thermal protection trip switch? I dunno, but it comes on.
They are fine:)
Mods feel free to delete the thread.
jandl100
03-03-2019, 12:40
Justin playing music at eleven and a half, shock?
Yeah, I can believe that! :lol:
Think this thread should be left up as a warning to would be neighbours [emoji23]
jandl100
03-03-2019, 12:43
half a kilowatt. :mental: :lolsign:
Sorry, I can't hear anything you guys are saying:D
Sorry, I can't hear anything you guys are saying:DI can believe that [emoji23]
jandl100
03-03-2019, 12:55
https://image.shutterstock.com/image-photo/young-man-huge-hearing-aid-260nw-251216401.jpg
500W....nah that's kids stuff. Even 1.8kW into my bass drivers isn't that impressive when a pal is using 3.6kW. It's not that I can't hear much with all the bass pressure, it's more that my innards are scrambled.
walpurgis
03-03-2019, 13:16
Hmm. I've found 8 watts ample in the past! :)
Well.....above 100Hz I only use 2W to 5W. It's a bit crazy 1.8kW on the bass and 5W on the rest.
Audio Al
03-03-2019, 14:10
Lift the amps and stand them on some wood battens , better air circulation , or you could mount a computer fan unit behind each one blowing low volume of air underneath ( Hmm I just said low volume :scratch: )
brian2957
03-03-2019, 15:01
Well , at least they're working Justin , and you will know what to do the next time . Wife telling you to turn it down :) I've got one of those too :)
Even the local deer were having issues with the noise.
https://uploads.tapatalk-cdn.com/20190303/be92ac917579ef9c11bb98bf144fd382.jpghttps://uploads.tapatalk-cdn.com/20190303/99845407323e503b82d379a6e3dac162.jpg
Lift the amps and stand them on some wood battens , better air circulation , or you could mount a computer fan unit behind each one blowing low volume of air underneath ( Hmm I just said low volume :scratch: )Either side of each mono are the output transistors. They get hot and the gap between each amp in the rack is inadequate. So those get even hotter as each amp heats the other one up.
The answer is not to drive them so hard for such a long time. They just get warm at normal levels.
Or move them apart in the rack which can be done but they have to be moved forward or backwards to space them, which looks bad.
Or rely on the thermal protection:D
Thing is you can only press that button 3 times it it's a full rebuild.
.
Just kidding [emoji23]
Justin, you are using hardcore speakers that drink watts like a Scottish alcoholic drinks Buckfast. Count yourself lucky that you didn’t damage your amps, and also you’ll already know that very small volume increases can result in a lot more Watts.
Neil, you are correct.
Actually I have to say I am impressed by the Accuphase's ability to cope with it aged 44 years.
The 211s never shutdown. A 400 Watt KT150 amp did. Many, many times. Granted only in triode mode at 250 Watts.
The 211s have an inbuilt protection mechanism. You can hear when they don't like it. So you never play beyond their limitations. Which is capable enough and they are the long term faves.
The last time I checked the Accuphase line up they were all a bit pussy powered into 4 Ohms.
AJSki2fly
05-03-2019, 11:24
Panic over. There's a push in button at the back that had moved out on one of them. Thermal protection trip switch? I dunno, but it comes on.
They are fine:)
Mods feel free to delete the thread.
I would recommend going to Specsavers so you can then see the button on the rear and at the same time you could get your hearing tested, I believe they offer a free service for this. :lol:
Spectral Morn
05-03-2019, 13:15
Great news its not damaged :cool::D
I know everyone is just pulling Justin's leg a bit which is as it should be but can I add a serious note . Why not get a bigger HiFi Stand with an additional shelf so that each power amp can sit in glorious isolation ? Not only will this look good but will also allow much needed air to flow over both units meaning you can abuse them to your hearts content so long as they still sound top class and just scream to the Wife when you need a drink snack whatever.
I have never even seen these units let alone heard them but your obvious attachment to them would suggest a little more care with placement is a good idea.
Spectral Morn
05-03-2019, 13:32
I know everyone is just pulling Justin's leg a bit which is as it should be but can I add a serious note . Why not get a bigger HiFi Stand with an additional shelf so that each power amp can sit in glorious isolation ? Not only will this look good but will also allow much needed air to flow over both units meaning you can abuse them to your hearts content so long as they still sound top class and just scream to the Wife when you need a drink snack whatever.
I have never even seen these units let alone heard them but your obvious attachment to them would suggest a little more care with placement is a good idea.
Justin doesn't need to. Contact the stand manufacturer and order longer spacer parts to increase the gap. A few inches might be all that's required, though clear air above would be better. That would still leave the bottom of the TV unobstructed.
AJSki2fly
05-03-2019, 13:53
Either side of each mono are the output transistors. They get hot and the gap between each amp in the rack is inadequate. So those get even hotter as each amp heats the other one up.
The answer is not to drive them so hard for such a long time. They just get warm at normal levels.
Or move them apart in the rack which can be done but they have to be moved forward or backwards to space them, which looks bad.
Or rely on the thermal protection:D
I think I understand the issue with each amp affecting the other from a heating point of view when turned up to naughty loudness levels. But why can you not put one above the over on different shelves, effectively separating them or have I missed something?
Bigger Spacers plus lifting the amps a little bit with feet or woodblocks will let air flow under and around and keep them that much cooler but the fact they are side by side might be the issue . I agree that moving one amp to another shelf would be by far the best option to give both units maximum breathing space .
Thanks for the concern.
As I said I can space them further apart in the rack as is. Next time I drive them crazily I will do that.
If I choose to drive them stupidly for long enough they will overheat no matter what.
I actually have higher spacers for the second shelf up, which would allow placement one above the other. I choose not to use them for one reason or another.
One reason is there's quite a lot of cabling being hidden from the listening position with this setup.
Powered by vBulletin® Version 4.2.3 Copyright © 2026 vBulletin Solutions, Inc. All rights reserved.