Amps that don’t impersonate space heaters.

I am most grateful for all of these intriguing responses. I am only familiar with Coda by name but I am obviously taken with many things spawned by Threshold. I didn’t see them at AXPONA but believe they have a presence in Chicago. Class D is also an intriguing idea. Again, I have scant personal experience but the dimensions and weight are most appealing to a person addicted to swapping out amplifiers and who will celebrate his 74th birthday soon. The fact that many suggestions accept balanced input a distinct plus as this is a cult I joined long ago. I wasn’t aware that Atmos-phere made a class D amp. Have always respected Ralph’s products. I have never owned one but OTL has always fascinated me since meeting ‘Gizmo’ at a CES in Chicago long, long ago. Again, appreciation to and for you all. 

You want a great amp that runs cool? McIntosh MC312.

I recently changed my electronics to Pass, but have to say that the MC-312 (and probably the MC-462) are great sounding, very well built amplifiers and they never get above warm. More specifically, the heat generated will never be felt from your listening position or in your room.

Seems like a semi-Coda thread going on here  I'll contribute.

Stay away from pure class A. 

Well, I have always thought this too, based on what I have read, where I am at in the middle of BC Canada this past July saw 23 days exceeding 30 degrees Celsius (86 F), 20 consecutive days exceeding 88F, with the highest temperature reaching 108F in that span. So yeah, heat from my system is a concern. But I read from others than the Coda class A units ran cool, so I gave it a go. 

I picked up a 100 watt Class A Coda to run my high channels on my maggies, while the bass is still powered by my Class D Apollon NCx500. Some may find this surprising: Both amps have been powered on for over 24 hours, and playing music for 2 hours. Using a digital thermometer gun, the highest surface temperature reading I can get on the Coda is 33 degrees Celsius, and on my Apollon the temperature reading is 35 degrees C. 

So I could claim my class D amp runs hotter than my 100 watts of class A. Go figure.

This of course doesn't give an indication of the total wattage consumed, but simply staying away from Class A because it is "hot" appears to be based on old technology, or simply a myth. 

I love my Proceed HPA-2!  Still around for 1200-1600.  Not bad for a dual monaural amp that retailed for 3500 20 years ago. 250/8 500/4 bridgeable.  I power a pair of DCM Time Frame 2000's to concert levels and neither amp or speakers break a sweat.  It also has somewhat more to offer HT as there is also a HPA-3 for folks that like all channels with the same amp characteristics.  I've owned mine now for 6 years and it does everything I could ask, and dream frankly.  Your system should make you smile and mine surely does!