C'mon name that amp ...please?

What about a Moscode 402Au;in home trial period and also able to roll different tubes if you likeand should have plenty of power.

I have the same speakers --- at least by brand (Montana EPS2's in my case). I highly recommend the Ayon Spirit 3 --- which can be had for well, well below your price range. I have that amp and it sounds amazing on my Montana speakers. Or... if you really want to spend more money than you need... go up a level in the Ayon line.

Another suggestion is by an amp from Montana --- those amps are made for your speakers by the very man who made your speakers... Peter Norbeak.

You're already used to having a lot of power, so I second Sufentanil's call for big brawny amps like the Krell 600 watters or the Plinius SA 250 - the small and expensive Pass Class xa series amps are beautiful in smaller applications but just aren't going to give you the volume you're used to. Don't know what ARC gear you are looking at, but Modwright doesn't make anything I'd use in a room that size.

Other Plinius possibilities that pop up for sale here with some frequency are the SB300 or SB301. I use the latter to drive Revel Salon 2s in a nearly 6,000 c.f. room, and it has a nice decay with good detail without sounding clinical or cold. The earlier model SB300 is essentially the same as the SB301 with some cosmetic differences and there's currently one listed for under $4K, and also an SB301 for $5K.

With your budgeted amount and willingness to buy used you're actually very well-positioned to make a serious upgrade. Just a few of the other possibilities available here in that price range are a Mark Levinson 532H for just over $6K (I auditioned my Salon 2s with that amp and really preferred the Plinius, but they are detailed), a Pass x350.5 that would fill that big room of yours nicely, a pair of the aforementioned Krell FPB600 monoblocks for just under $6K, a Krell Evolution 302 for just under $6k, etc. etc. etc. Happy hunting!

Go for a great hybrid amp for the great sound of tubes without the hassle and heat. The Aesthetix Atlas stereo amp is wonderful as is the Moscode.

What do you guys think of the ARC HD220 hybrid amp? That was the ARC model I was thinking of in original post. I have read the Audiogon review where the guy loved it and then 4 months later didn't, but I suspect he is a true "tuber" and embraced the added dynamics and assumed clarity for a short time only.