ARC Reference 10 melting polycarbonate cover

Theo, I can't hear any difference with the cover off. Though I have heard this theory for years. I tried this experiment years ago with my LS25 mk2 and could not hear any difference then either.

The problem with the Ref preamps is that the top of the 6550 tube is very close to the poly cover. This causes a slight upward circular bump in the cover. It still happens with proper ventilation. I have an open rack with about 5 inches above my Ref 5se.

That said, The Ref 5se is an incredible preamp. I can only image how much better the Ref 10 is.

I had the problem with my Ref2 SE phono stage. I thought I was going to have to buy a new rack as the one I have only has about 3" of space above the ARC and the next shelf. The poly cover was starting to bow above the 6550.

A cooling fan solved the problem. I think the fan is a good idea even if you remove the cover. Cooler operation equals longer life.

Egrady, what type of cooling fan did you get? Is it battery powered? Recommendations?

I have a Ref5 SE that has the same polycarbonate cover. It is sitting on top of my rack with the ultimate ventilation. The cover is STILL WARPED! It has nothing to do with adequate ventilation. Lostbears nailed it, it's the 6550 power tube. Flipped it over and in 5 minutes it bowed again. I am ordering a metal cover to replace the plastic POS!

Be prepared to spend $250 for the metal black or the poly, and $510 for a silver one...