Looking for Silent Fan Cooling f my ARC Tube AMP

Correct me if I am wrong, but I thought that blowing air onto hot tubes can result in "microcracks" and is not recommended.

That's what it says in my Jadis manual as well. However, ARC does use fans in some of its models (I think my M-300/Classic 150s had them; that I can't recall entirely will testify that their noise was not intrusive), and I believe they make them for installation in enclosed rack/cabinet enclosures. You might want to check with ARC about this--what model amp do you have, anyway? You could ask ARC if a fan is really necessary for your application as well.

My VT100s have fans in them. Fairly quiet ones, too. Given the cost of retubing one of those guys, I hope I'm not developing "micro cracks!"

Might check an electronics parts outfit, the fans look like the 5 1/2" ones found in computers. I think they make "whisper" versions that are pretty silent.

I put a Radio Shack fan on top of my Audio research VT 100 MK II and put a variable speed fan potentiometer from Home Depot. This lowered the fan speed and also the noise from the fan. This profect only cost me around $20.00. I put the fan so it blows across the amplifier to circulate the warm air away from the unit. Not blowing directly onto the tubes.
Hope this helps
Kevin

Kevyo is right. You want a low-speed one for two reasons: prevent problems with tubes and low noise. Rogue uses one that is amazingly quiet and you may be able to find out from them what brand it is. And don't blow it direct on the tubes.