I have been mostly using Pass Labs amps, which, as a SS, has a tube like sound. Now I am thinking that if I like the tubes sound of Pass, why not try tube amps, particularly VAC. I have Soundlabs electrostatic speakers, which are very fast, so I am looking for a tube amp >80W with some even harmonic sound. I have heard good things about VACs and I was wondering what type of sound VAC amps have. I am particularly interested in used VAC amps which may be more reasonably priced (assuming they are reliable). I would appreciate hearing from VAC users.
upper vacs and pass amps are creme de la creme of each type of amplifier (among a handful of others of course)
i would agree that vacs will provide more expansive imaging as well as ’bloom’ in the midrange and upper bass, and less attack and solidity on deep bass
vac amps in my opinion do not roll off the highs much, may sound prettly close to pass in that range
@chungjh, I’d call Wayne at Pass. Two things still come to mind. Re-check bias on your Pass amps, re: slow warmup. Some do get sent back and get re-checked after some run-in time. Concerned for you that your SL 545s might suffer with any lower power tube amps. I run capable 120w KT150 mono tube amps with larger transformers myself, and I’ve heard your same speakers with my 120w tube amps. As I recall it was still on the edge of being "just enough", maybe. I still wonder if your preamp is not driving the amps well enough. Separate topic, ask Wayne. Read this article to refresh thoughts about the type of amplification to make the 545s sing.
(At 86dB efficiency with an 8-ohm impedance, the U-545 needed more wattage than current in amplification, so a high-output Class AB would be more appropriate generally. But the XA200.8 is Pass Labs’ most powerful Class A monoblocks in its ‘High Current’ series, occupying only two chassis and second-in-line to the company’s four-chassis, $85k Class A Xs 300, therefore provided the necessary wattages in high-current drive and propelled the panels to enormous scale and performance)
I don't think VAC amps can be characterized with a house sound, as sound from their 300B based Renaissance amps (30/30, 70/70) is very different from the KT88 based Phi 200.
The VAC Phi 200 has very robust bass, but lacks transparency, air and sweetness of their old Renaissance series amps.
Additional brands you may want to consider: Air Tight, Quicksilver, Music Reference and Manley
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.
Yes in monoblock mode, with Kharma speakers. Very holographic representation but not romantic. Very well made almost to OCD standards. I have the VAC pre and in a sort of conundrum to go with VAC 200IQ myself.
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