Tube amp $2-3K used

The Atma-Sphere amps, at least those made in the past decade, are extremely stable, you can even remove output tubes while they are playing (not that I recommend this). The two caveats in your situation are that although they can be run single-ended they are really designed to be operated in the context of a fully balanced system and that they don't especially like low impedance loads (the S-30 particularly).
SF amps can be serviced and/or upgraded by the Parts ConneXion which is run by ex-SF staff.

art audio concerto's are autobias, zero negative feedback, under $2K used.

Not being a tube god, I went to the ASL site and was further confused. How do you choose between the KMP Fox DT, Explorer 805 DT and Monsoon DT (a junior Hurricane). They are similarly priced and have different tubes. Any reason to pick one or the other?

Glai, any thoughts you have will be appreciated. Plus where did you hear the ASL amps?

Here's another question about an ASL amp although it could apply to some other manufacturers as well. The Explorer 805 DT seems too good to be true. SET, 50 Watts, fair price and built in meter. Seems like a lot of power from 1 tube.

I have never heard the Explorer but I bought Hurricane from Divergent Tech directly. They offer free shipping & possibly 10% discount if you don't have local dealer. You can call Div. tech for local dealers. They are a helpful bunch in tech support and have good recommendation on NOS tubes that work well with their amps.

From speaking to the tech support at ASL, they say the 1009-845 is their best amp with the Hurricane second (if you need more power). The Hurricane has some amazing reviews and the 1009-845 is even better in my system.

Check this site out.

www.high-endaudio.com/RC-Amplifiers.html

I found their opinion of amps accurate but I could not agree with their speakers or CDP recommendations. According to the reviewer, Monsson does not quite have the magic of Hurricane.