Aesthetix Rhea & Calypso Tube Upgrade

i have a rhea, that had the stock tubes in it. i replaced them with a set put together by jim mcshane.
much livelier sound, still new production tubes, jim just mixed and matched brands for the different stages in the pre. i'm happier with the sonics of the new tubes over the stock set.
one thing to be aware of with the rhea. completely power down and let the unit sit idle for at least 20 minutes before pulling a tube. if the caps aren't discharged when you pull a tube, you risk damage to the circuit.

Check with Glenn Buckley at Aesthetix. I've found an excellent replacement for the 12AX7 is a 7058 tube. NOS 7058s turn up on Ebay in quantity every once in a while at reasonable prices, but are not especially cheap when bought one or two at a time. No ideas on replacing the 6922s, and I'm not even sure what types (6922/6DJ8/etc) i'm using now in my Aesthetix and Rhea. Great components, by the way. Power them down, as Corby recommends, before changing tubes.

Good quality 12ax7 or 6922 tubes cost from a reputable dealer will run you $30/ea., so you're talking about $420 minimum for a complete retube. What does the factory charge for a complete set? You might want to talk to the factory about whether there is a specific tube position you might want to splurge on. Really good editions of these tubes can be had for under $100/ea.

I just checked Ebay (8/8) and there are 10 of the 7058 tubes I mentioned going for a total of $70, buy-it-now. These are NOS. That's more than I usually paid, but not bad.

What do you guys consider to be an 'Expensive' tube(s) ?