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

Pehare, I neglected to mention the amp of Rogers that should be of particular interest to Magneplanar owners. The RM-300 is a 300 watt mono block (with the same basic circuit as that of the RM-200) which may be the best tube amp available for driving Maggies. Why? Because, unlike all other tube amps of which I am aware, it's power output increases with falling impedance, not decreases. Many Maggie owners have to settle for solid state amps because tubes don't like the very low impedance load the speaker presents an amp, when they would rather use a tube amp. The RM-300 makes that possible. Unfortunately the amp is $9000, $18,000 a pair. Still, that's less than a lot of the more well known and owned amps that Maggie users buy.

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.

A long time ago I worked in high tech aerial photography and we used Zeiss cameras. We lost a lens cover which is a square aluminum plate with a tab on one end and a handle and latch on other. Zeiss wanted something like $3K for the lens cover to go onto a $400K camera. Of course, you can consider that it is designed to ride in bottom of a plane and if something comes loose it could be a big problem, etc. We took another one to a local machine shop and had it reconstructed from scratch for $500 and it worked perfectly.

In the ARC case, the customer alienation factor of having someone sitting there looking at their amp and thinking of how they got ripped off every time they look at it would not be worth it in the grand scheme. The company's success will not rest upon the sale of $510 covers.

why have a cover at all? most of the RF is generated by ICs and comes in via the power cord anyway. if its dust cover you're worried about get a nice room air purifier. components frequently sound better with the cover off. plus you will have easier access to the component for all that tweaking.

"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.