Perhaps Paul or Bascom can address this, I would like to know the normal temp range when the amp is on standby and when it is playing music. Thank you and your feedback is greatly appreciated!
You mean to ask in degrees? I have never measured it. In standby mode, tubes off and front panel logo light off, the amp runs quite warm to the touch, but not hot. In operate mode, it’s quite a lot warmer. I just use my hand on it - and in operate mode, once it’s been on for some time, the heat sink’s almost too hot to hold my hand on for any length of time.
Thanks Paul. I thought your engineering dept will have that data available. My situation is similar to yours for both standby and operation mode. I think I am keeping my BHK 250, it is still breaking in but it is sounding better and better every day when I go home.
Excellent! 
I know the engineers actually do have that info but I don’t. I suppose I could get off my lazy ass and go ask…
Paul,
Thank you once again. Any updates on the PS Audio speakers project? Will start saving money for that
Not much - stuck in the mud with drivers. Arnie wants an exotic driver - and can’t decide which: a carbon fiber/Kevlar sandwich or titanium. We have have tooling made for both so we can decide. 
I was excited when I first heard the news. I passed on buying a used pair of IRS beta because of lack of support. I am confident that you guys will stand behind the speakers when they are out.
Reviving an old thread:
@Paul I just took delivery of a new 250 a couple of days ago. She’s breaking in nicely and quite the upgrade over the M700 I’ve had for a couple years.
I’m keeping an eye on temps to learn what is normal using an IR thermo. I’ve noticed a 10 deg F difference between the left and the right heatsinks, the right being the hotter at 110F and the left at 100F give or take a deg. depending on where I measure along the heat sink.
These temps seem very reasonable to me but the delta is curious. I would have thought the two sides would be symmetrical in dissipation.
Please advise - I’ve also sent a note to support and then found this thread.
Glad you’re enjoying it over the M700s. It’s certainly not a minor upgrade.
Operating temp seems very reasonable but the delta has me curious as well. Sure, a handful can be explained by slightly different bias, but how much is reasonable. The only time our tech guys have been considerable concerned is when it was NOTICEABLY hotter on one side. Like lukewarm on left, burn your hand on right.
Yeah, 10% is potentially significant but I guess it would depend on the bias delta. If a 0.1% difference in bias results in a 10% increase in heat, no issue but if a 10% bias delta results in a 10% temp delta…that may be a more of a concern as the channels would be out of balance. They certainly sound balanced to my ears but I reckon the transition from A to AB mode is pretty seamless.
Just an observation I thought worth confirming with the engineers
Agreed. Keep us posted when the tech guys reply back to your email. If you don’t hear back from them in a day or two, I’ll be sure to get you an answer.
Thanks. I should add for posterity, the amp has been on continuously for 45 hours and playing low level for ~16 hours of that time. Should be as stable as it’s going to get.
Perhaps I’m at it’s idle temp. I’ll push some volume for an hour and recheck temps and balance.
Forgive me but the physicist in me just wants to say the delta is not 10%, technically it should be measured in degK where 100F would be 310.9 and 110F would be 316.5 or a delta of about 2%. Hope that eases your mind a bit.
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Hmm, that only serves to confuse me as converting to another scale certainly changes the measure but not the real temp difference.
Why K and not C? If converted to C it’s a 8.7% delta. Regardless, I’m only looking to understand if this is within the acceptable tolerance regardless of the measure used.
K is used because it starts at true or Absolute Zero and it’s the unit which all temps can be compared apples to apples. It is really nitpicking and doesn’t make that much difference in this case as the fact there is a delta is probably more important than that it’s 2, 6, or 10%. C while each unit is the same as in K has an arbitrary zero point as does F which also has different units.
Good to know, thanks.
The modest temp delta left and right is of no concern per Scott. If it increases or reaches the point where it’s too hot to touch for more than a few seconds then something has gone awry.
Good to know and thanks for keeping us posted. I’m curious if I’d be able to notice that difference by toughing them.
It’s noticeable but not dramatic. I was simply measuring with an IR thermo to know what normal is in it’s installed location which is enclosed with vent holes
A minor adjustment so the 6.8dBa fans are pointing directly square to the heatsink has dropped standard tune cranking temps from 110F and 100F to 95F and 93F. Shrinking the difference considerably and reaching exceedingly long-lived temps for an enclosed cabinet.
‘Remember friends heat kills’
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