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

Here's a $20 solution. I purchased a small 3 way fan from AC Infinity. Place it on top of the preamp blowing up. On slow and medium speeds, it is not audible. It cools down the top of the preamp quite effectively. Plugs directly into AC outlet. May also prolong tube life.
Randy

Neglected to mention, the 6 inch fan has rubber feet so won't scratch the preamp cover. It is available through Amazon. I use it on an ARC Ref 5se preamp.