But that is the point. It is the amps that generate the heat. It is the delicate processor boards that are highly heat averse.
So that is why the receiver concept is such a terrible idea and I would NEVER consider owning one.
As I have said before Peter Walker of Quad was asked repeatedly if Quad would put a receiver in their range. He proclaimed NEVER! He was obsessed with making his products reliable. He did, and took every failed unit hard no matter how old.
If you go on eBay you will see many, many units from his tenure still working fine and commanding good prices.
His approach is the correct one. Under his tenure he never had a marketing department and like me hated the breed with a passion. As usual he was right!
All my 14 power amps in use, four preamps and two FM tuners have Quad labels from when he was at the helm. One is 58 years old. Those units are among my prized possessions. We need more of his ilk and marketers on the dole.
You know I am a big fan of Peter Walker's designs... and have no intention of letting go of my 606 &707 amps...
But - in the Onkyo SR876 and Integra DTR 70.4 (and many of their siblings and competitors) the HDMI and DSP chips used far more power at idle than the power amp circuits...
The get the power amps similar amount of power to what the HDMI&DSP used in those generations, would have required completely unrealistic loudness levels (like 50W/ch continuous into 5 or 7 channels).
At the time I used the onboard monitoring to track fan activation and power amp temperature (which the firmware provided access to) - there was no way of tracking HDMI and DSP temps.
While the power amp was idling along at 36C... the case just above the DSP and HDMI chips, was so hot that you could not touch it.
So no - in those generations (from circa 2005 to circa 2015... and perhaps a few years later depending on the brand) - under any form of semi-ordinary usage, it was the digital HDMI and DSP chips that generated most of the heat, and absolutely NOT the power amp circuits. (and yes the boards on which the chips were mounted were heat averse, and failed at a much higher rate than they should have!)
The Audio engineers designing those generations of AVR's had grown up with the long term assumption that the power amp generates the heat, and that the "preamp" / "processor" doesn't - they designed the AVR's accordingly, resulting in quite dramatic failure rates. (my guess as to root causes!)
I am very very pleased to see (and feel/measure) that the current generation does not appear to suffer from this major flaw.