Large amp fan for Classe CAV150

A CAV 150 or any amp with 36 output transistors and 28 caps is likely to run warm to begin with, and bridged, well you feel it now. You are on the right path with a good fan if you must. I'd be tempted to run 1/2" spacers on the top cover and blow air across or fab up another topic cover with holes in it to carry hot air up/out faster.

Agree with the comments above with regard to bridging amplifiers. Yes, you increase power output. Unfortunately the amplifier now sees the speaker impedance load cut in half, ouch! 4 ohms is now a 2 ohm load. Considerably increased work for the driving bridged amplifier.

Charles 

I have had good experience with the AC Infinity T9 top fan cooler for my Rogue Stereo 100 amp. You can set the temp that it turns on and off at. It is pretty interesting how fast tube amps heat up. The cooling fans do a nice job.

Yes, you are killing your amps doing this... bad idea dude.

Has anyone ever measured the sound level of the ACInfintiy T9? Their specs say 21dBA but don’t mention what distance from the unit where that level was measured. I wrote to their tech support and they said they cannot answer that ("we are unable to provide you with the exact distance from which our engineers measure the fan’s noise levels. From my understanding, the dBA ratings are averages of different distances")

Has anyone ever measured the sound of a T9 by itself at say 1m?

Without knowing the distance from the device where your measurement is taken it doesn’t say much. For example, my backup generator is supposed to be a "quiet 74dB", but what they don’t tell you is the generator industry measures sound levels 22’ from the generator. If you're standing next to it, like at 1m, its around 98dBA, which I consider LOUD.