[dilznoofus]

I

[Wayner]

Don't plug up the air vents first off. Then I would suggest that all amplifiers need to be all by them selves. Let them breath. Do you want a number...6" from the top, bottom and sides. How's that.

 

[warnerwh]

These amps run very warm. I only have about 4" on top but my rack is open on all sides.  The heat sinks are actually sitting out the back of the rack too. The entire case gets good and warm. Remember too heat is the enemy. I want my amp to last me a very long time.

[rustneversleeps]

I ran my Fet Valve 550 for a few hours until the rear heatsink was nice and hot, then I opened up the cover (with AC cord unplugged, of course), and touched the TO-3 transistors with my fingers. Surprisingly, the transistors didn't get all that hot. So I think as long as the heatsink has enough room to breathe, it should be OK.

PS. the transformer didn't get all that hot either.