Best sounding,reliable, tube amp below $700 used

Thanks Autre, that helps a lot.

I have owned both Adcom and Rotel(RC-990/RB-980BX) pre/power combos. As great a value as both are, they can be hard, edgey, and dry as all getout. Moving to tubes will be a revelation. I'd suggest selling your Adcom preamp and use the extra dollars to get a better tube integrated, it will proably degrade overall performance.

The Revels at 87dB would probably benefit from 20-40 wpc of push-pull amplification, depending on your musical tastes and volume levels.

Buy used to maximize your purchasing power and look for Jolida(Jolida JD-302B), Antique Sound Labs (AQ-1003 DT, AQ 1001 DT), and Consonance Opera( M99 Plus, M100 plus) integrated amps.

All three of those manufacturers have a good history and reputation for low-priced tube gear.

A rebuilt with Curcio power supply mod-Dynaco ST-70 with very good tubes might be the ticket and surprise you too.
I replaced my Threshold S/300 with the Dynaco which is more musical and doesnt have the Threshold midrange dryness.
The Dynaco doesnt have the power of the Threshold or the bass control,but believe it or not, the Dynaco is not that far behind (with Curcio ps mod and vg NOS tubes) which adds a much improved midrange tubes are known for.
A few for sale here within your budget.

Well, my system now is comprised of an Adcom GFP-750 preamp, and PSB Alpha speakers, but I will be replacing the PSB with Revel M12s in the near future.

As for amps that I've heard, I really havent heard that many, but I have liked the sound of the Krells and Levinsons. I've listeded to a Rotel integrated and wasnt too impressed with that. I also had a Marantz 2330 that was okay, but not outstanding. I seem to like systems that bring out a wide soundstage, and detailed vocals, especially female. Does that help at all?

What type of speakers will the amp(s) be driving and what are their specs?

And what some tube amps that you've heard and liked along with others that you didn't?

Thanks for the replies, I've read about the mini mites on an old post here, and also the Conrad-Johnson mv-55 seems to also have a lot of backers. Please keep the opinions going.

Agree with Mwilson--QS Mini-Mite Monos are excellent for the price ($998 new, ~$650-700 used).

Cayin TA-30 integrated. Essentially the same as the Primaluna Prologue 2, but goes for $600 to $700 used on Agon. They sell really fast though.
Extremely well built, hand wired, can run in SET mode or 35wpc with EL-34 OR KT-88's. Very quiet and holographic.

Someone just listed an Aes/Cary Ae-25 Superamp that would be very hard to go wrong with. Apart from that, Quicksilver Mini Mites (monoblocks) also come to mind. Good luck!

Berning EA-230's...some go for about that much...I think at that price they are a steal.

I'd investigate the Onix SP3....very good, can pick up used for around $500.00. Check 6Moons for review.

Have fun!