Looking for Silent Fan Cooling f my ARC Tube AMP

Usually the higher priced squirrel cage fans seem to be more durable as well as quieter. I've used these in high power HF tube amplifiers. In this case the bottom of the cabinet is pressurised and the air moves through a ventilated tube socket,up around a chimney enclosing the tube then out the top of the cabinet. This seemed to keep very big and very $$$$$ tubes happy.

Get a cheap very quiet mini desktop fan 4" dia. at target for $8.00 will do you just fine!! it's very very quiet

Whether the air is 'forced' across the tubes or 'drawn' across the tubes makes no differnce since it is the temperature of the air that makes the difference and it is the same in both cases.
At any rate, if you can't hearthe fan then the amount of air flowing isn't high enough to be any 'danger' to the tubes, forced or induced.
Salut, Bob P.

Vornado Zippi totally silent. I was using it when I was keeping a tube amp in a rack with somewhat limited shelf space. I had the fan blowing upwards over the top of the amp so the heat would blow out the side of the rack and not heat the upper shelf too much. Worked perfectly.

I find pro cool fans are very quiet.
Some assemblies have a thermostat so she'll kick in at a certain temp and off as well at a certain temp.
I use two and I can't hear either of them.
Also there is a temp display.