Choice of tube amp?


I`ve auditioned some tube poweramps lately, the Rogue Zeus and the VTL S-400. This has left me contemplating a change from SS to tube power amplification.
My system consists of: APL Hifi NWO-2 cd/tube preamp, Pass Labs X350.5 and Martin Logan Summit. The APL and Summits are here to stay :) The Pass is up for discussion :) The Pass, in my setup, is a little dry sounding and doesn`t involve me as much as I know the APL and Summits are capable of. I`ve researched a little more than Rogue and VTL. I`ve been talking to VAC, Audio Valve, Wolcott, CJ and Cary. Any suggestions? And how they will compare to the Pass in my setup? If you feel my question is dumb or that you need more information, just tell me :)
mibviking
Ralph/Atmasphere,

I'm confused by your following statement made in your 08-02-06 post:

"If you are running ESLs it is the nature of the technology that you will have to run tubes for best results."

vacuum tubes have always been voltage devices & have traditionally never been good at driving low impedances. That's why McIntosh tube amps often use autoformers at the output. IMHO, that is also why your amps use several tubes in parallel to both get the output power up & the effective output impedance lower.
How, then, can you state that tubes work the best w/ ESLs?

Also confused by this statement from the same post: "but it is only half successful as you still deal with a dry coloration that is inescapable with most transistor amps due to the characteristics of the speaker (including the impedance curve)."

The low(er) impedance of the ESLs should play superbly into the hands of a ss power amp as sourcing/sinking current into a low impedance node is where such designs excel.
I can understand & concede on the "dry colouration" aspect of ss amps vs. tube amps.

Sorry for the ignorance/stupid questions. If you could shed more light on your statements, I'd appreciate it. Thanks!
Bombaywalla, the first thing to do is drop the notion that tubes are voltage devices and transistors are current devices. While it is true that tubes run more voltage and less current, and transistors more current and less voltage, to think in black and white terms in this respect leads to confusion. Both devices actually are power devices. The two appraches do behave differently, but to ignore the power aspects of them is to ignore Ohm's Law, the fundamental law of electricity.

The Quad has an impedance curve that is not based on resonance; it is based on capacitance. As a consequence, at 50Hz (where there is a realitively high impedance) it needs the same amount of power to make 92 db as it does at 10KHz (where the impedance is much lower). An amp that puts out 'constant voltage' (i.e. most transistor amplifiers) will be bass shy and bright on a speaker like this. OTOH tubes will *attempt* to put out the same power with respect to these two different impedances, making for more linear response.

It is true that the newer Quads have lower impedances than the older ones (ESL57 and ESL63). This is an attempt to make the speaker more compatible with transistors, but ignores the very nature of the speaker itself. Thus tubes do have more troubles with the newer models. The ZERO is a solution, but Quad ought to rethink the scenario and at least offer a high impedance tap for tubes and a low impedance tap if you insist on transistors. IMO your investment in the speaker and transistors is not good as you will not realize the performance of either; quite simply its a mismatch.
Mibviking, you should auditon the CAT JL2 (I think the JL3 is overkill). I purchased one used about three months ago
and it is the best I've ever heard. I am a long time user of VTL, Manley amps and did hear the VTL S400 at the show in NYC two years ago. The VTL S400 sounded very good and it is hard to compare from a show audition but there is something about the 3D presence that the CAT has that I haven't heard from anything else. My CAT is not even the latest production which from users that have heard the older model and compared it to the latest (JL2 Sig MK2), claim it is a substantial improvement. I also went to a local high-end dealer and heard the Wilson Maxx2. The amp he used in that system was the VTL S400 but it was out for repair.

Bart
I got the Wolcott and I`m now in the tube rolling stage. One of the 6922 input tubes from Electro Harmonic started making noise after 30 hours. I replaced them with Mullard (Made in Holland)E188CC SQ from the early 60s, huge improvment. Now I`m trying out Tungsram (Made in Hungary) ECL86 from the early 60s for the drivers, great sound but one of them haf a weakness where the pins penetrate the glass and had to be taken out. And left I have 8x SED "Winged C" EL 34s to be tested later :)