Tube Amp for Green Mountain Audio Callisto

Consider also the Atma-Sphere M-60 monos...

Also, a VAC Renaissance 30/30 or 70/70 would be incredibly sweet.

There are used versions of all of these presently for sale.

Blue Circle gear has great synergy with GMA speakers. Disclosure: I am a Blue Circle and GMA retailer, Departure Audio. The DAR and FtTH ate hybrid integrated amps in the Blue Circle line. The new GDC integrated, while not a tube piece, is a terrific value at less than 2K and also a great match with GMA speakers. All of these have more than enough power to get everything out of the Callisto's. Blue Circle is one of the few lines GMA enthusiastically endorses with their speakers. Roy and I will be demonstrating these systems at some upcoming shows.

Srosenberg,

95 dB peaks at that distance is a far different story than 80 dB - in fact, you need about 32 times the power! So, forget what I said about a 300B and definitely forget about the 2A3! :)

(I know you didn't indicate you were looking at SET specifically but I thought I'd throw that out there.)

IF you are interested in SET, an 845 or 805 design would still serve you well. Or, actually paralleled 300Bs for around 20W.

I have a Response Audio/JoLida 60 wpc tube amp, as well as a Mapleshade-modded 18 wpc Scott. Both sound fantastic with my Callisto. With it's 90 dB rating, most any amp over 10 watts will drive it. Basically, it comes down to quality versus quantity with this speaker- although more power is always good for speakers IMHO. enjoy!!!

I would make sure whatever amps you choose have a "zero-negative feedback" option or are simply "zero-negative feedback" amps. Roy's design is both time and phase-aligned, so, personally, I'd only put hardware in front of my Callistos that also maintain the time-domain integrity of the audio signal.

I have only use Ayre hardware with my Callistos, but I have owned a set of AES Sixpacs and thought they sounded great. You can run these amps with zero-negative feedback. They only have a couple of drawbacks - they produce a bit of heat and with 12 EL-34 power tubes, they ain't cheap to re-tube. That being said, if I was in the market for tube monoblocks, the AES Sixpacs would be on my shortlist.