OK, curiosity got the best of me, I had to check back to find the reference. Turned out tomatchison was correct as I found it in Issue 2.
But here is the most interesting part. Copper is published by Paul McGowan and folks at PS Audio. And PS Audio introduced their new "super amps" designed by Bascom King a bit over a year ago, the BHK Signature 250 and 300 monos. Like Frank, Bascom is a designer with long years of experience and one held in high regard, so when he was challenged to design a new no-holds-barred amp for PS Audio he chose to utilize vacuum tubes for the front end driver stage and MOSFETs for the output stage. I'm not suggesting the AVA 600R and BHK Signature designs are identical, but the basic topology seems to be the same. The BHK Signature amps do have fancier metalwork enclosures, but they should offer something more for their $7,500 and $15,000 (per pair) prices.
Anyway, I found it interesting that a reader of the PS Audio publication thought enough of his AVA amp to post it there.