How would you characterize the VAC tube amps?

Electrostatic speakers sound best with tube power amps.

I suggest you look at atmosphere or VTL.

They  are both popular with sound lab owners.

Not that it's meaningful, but that VAC Phi Beta 110 integrated amp is one the most beautiful pieces of electronics ever made. Kevin seems like a nice cat- talked to him many moons ago about a line stage. (I should have bought that integrated amp when it was still in production, though I had little need for it then or now). 
bill hart

i have known kevin hayes since the late 1980’s - was an early owner of his 4-chassis pa90c el34/kt77 amps which put him on the map with TAS and Stereophile rave reviews back then when the accolades meant something substantial

i do agree that his amps over the years did not perform the same (each design had their pros and cons, specifically tied to the power tubes employed) but like all great designers they have a target sound character in mind

in kevin’s case i would say he tries to voice his amps to have an expansive image, a good deal of high end energy (for tube amps) to support the imaging/air, a silky slightly romantic midrange, and tuneful/middling to good (not great or very deep) bass.... i think his phi models tried to compensate with stronger bass from his successful earlier lines using kt88’s, but he lost some transparency and some midrange magic... i think his 300b based renaissance series are still his best sounding (most midrange magic, air, and ever slightly rolled treble)... but he has gone WAY up market in recent years ... i have not heard his more recent megabuck stuff which i am sure ’has it all’

I’ve heard a lot of tube amps not the VAC.. I’ve heard Pass: he’s  very detailfull, musical..but for me the best tube-amps are: Ear Yoshino 509 (2x100w. Monoblocks) ,and the Wavac 805 m ( 2x56w). I thanks all of you for writing something about VAC, because he’s on my list !

I used to own the entry level phi160IQ. Compared to a 150 watt SS, its bass was a virtue. Very alive, good bandwidth, a little forward and modern sounding as opposed to a romantic. Actually I believe it was more forward than my ML 532H. It was the wrong choice for my speakers, but I do miss the smooth, charming midrange.