Cool it!

I do not use any kind of cooler on my two-channel analog system, even with its 100wpc tube amp. It's just not needed.

However, I found that modern multi-channel AV processor/receivers certainly are in need of additional cooling (mostly due to the A/V boards, I think) so I utilize a Cooler Guys twin fan cooler on top of my Integra receiver that draws the hot air up and out of the unit and allows it to run much cooler after a double feature movie night in my HT room.

I use Class D.  Very efficient and not much heat generated. 

Fans & Cooling = Noise.  Not a good idea.  As long as their is space around the amp, all is good.  My tubes put out some heat, but the manufacturer already knew that when they created the design.

I live in the hot south and my tube amp and tube pre amp are located in a equipment closet. So I have a 10" fan set on low softly blowing down on my gear. Its still pretty warm in there, but not hot

I just had an AC company run 2 more ductwork lines to my room. Its a nice 68 degrees now. I also use an Aircom fan on top. All this should increase longevity and maybe performance. I have a 600 watt amp and its a room heater.