$510.00 for an Aluminum cover for the ARC Ref. 10?

10-30-15: Lostbears
" ...It is a design flaw and ARC knows it."

Hmmmm, no it's not a design flaw. If the unit is placed on top of a rack and air allowed to circulate freely around it, then the top will not warp.

However, if ventilation is restricted, then warping is a possibility. For those users, a metal top is offered.

You could think of the acrylic top as "the canary in the goldmine." I think it's important for gear to be properly ventilated ... especially tube equipment. And I haven't had any problems with the acrylic tops.

11-03-15: Statman
" ... This is for Cleeds, you work for ARC? It is a flaw ..."

No, I don't work for ARC.
I haven't had any problem at all with the acrylic lid on my preamp. It sits on the top of my rack, though. It's very well ventilated.

"11-09-15: Geoffkait
... why have a cover at all?"

One good reason is because the electric current inside of a tube amp or preamp is potentially deadly, often for quite a while even after AC power is turned off.

"11-09-15: Brf
Will ARC give me a $510 price reduction if I buy a Ref 10 without a top cover?"

Why don't you ask your dealer?
There seems to be no problem with the acrylic cover when the unit has sufficient ventilation, btw.