the best 'tubey amp - warm,smooth,liquid' ?

If you want the system to work well with tubes, the first thing is to sort out if the speaker is OK with that. Take a look at
[ur]http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php[/url]

If your speaker is designed to work with amps that are voltage sources (Voltage Paradigm) you will do a lot of struggling to find a tube amp that will work with it.

Good Luck!

Zabiaud, if you really want to find out what tubes can do, you will need to think about getting a different set of speakers that are higher impedance and hopefully a little more efficient!

Four ohms sort of works with transistors, but any tube amp made will not be sounding its best on 4 ohms. Tube power is expensive, which is why before transistors showed up most speakers were considerably more efficient.

Actually, four ohms does not work all that great with transistors either. Sure, you might get more power, but the distortion will be higher and you will hear it in the form of brightness/harshness. A transistor amplifier will sound smoother and more detailed driving a higher impedance. Plus, speaker cables are far more critical for 4 ohms- they should never be run distances of over 5-6 feet, wheras with a 16 ohm speaker you can get away with hardware zip cord and it will work pretty good. Something to think about.

can we say 'the big speaker systems like proac d40 or b&w (4ohm) generally don't go well with tube amps'?

Yes, and I can take it a step further- 4 ohms does not go well with *any* amplifier, if **sound quality** is your goal. If *sound pressure* is your goal you will get some small benefit from using 4 ohms with transistors, but even transistors sound better into 8 or 16 ohms.

IOW if you are a loudspeaker manufacturer this is a simple way to get your speaker to seem smoother and more transparent- design for 8 or 16 ohms instead of 4.

Audiozen, FWIW Joe (Trelja) has been in the audio business for some time. He used to work with Bud Fried and also imported the Consonance line.

The input stage uses a 12AX7 configured as a long-tail pair phase splitter using a large tail resistor to ensure constant current source operation.

:) He must be new to differential operation. You can't do that effectively with a resistor like that- you will need a proper constant current source (CCS) if you really want it to work right.... just say'n

^^ none of which has anything to do with my prior comment. Look at the quote I made- the comment was addressed to that.