How do tube Watts compare to SS Watts?


I have Theil 2.2 speakers, which have a low sensitivity (86dB), but I would like to get an intergrated tube amp. Or even all tube. But I don't know how many tube Watts I'll need to drive the Theils. My guesstimate is @ 50wpc for intergrated tube amps, but that could be wildly off. Are their mathematical conversion formulas? Second, if there is a rough range, might you be kind enough to suggest a few worthy candidates that, wheather new or pre-listened, are under $1,000 USD (e.g., Cayin model xxx). Thank you most kindly.
rascal52240
I had trouble driving CS2's with Quicksilver mono amps that were rated at 60 wpc. The room was about 12 x 20 and I thought I needed tubes to make the Thiel's sound smooth and sweet but when I switched to a smaller high current SS amp they were controlled, not sloppy.

Best advice I can give is try a tube amp with some guts and use the 4 ohm taps if it has them. Or get a SS that doubles into 4 ohms.
Watts are watts. Tubes sound better than SS when they clip and its more subtractive. SS just sounds crappy when they clip.

Some manufacturers of solid-state amps have taken this into account. Levinson amps, for example, have a built-in smoothing circuit that eliminate this harsh clipping sound when the signal gets close to the supply rails. Another that comes to mind is McIntosh, whose PowerGuard circuitry has received acclaim as an effective mean to end hard clipping.

As for the Watts question, in theory it shouldn't really matter if the amplifier is tube or solid-state, because strictly speaking 1 Watt = 1 Volt x 1 Amp. In practice, the specification is approximate, so you can expect an amp with a bigger power supply and lower impedance to sound louder with the Thiels. Also, all amplifiers differ in their "power margin" above its nominal power, depending on their circuitry details.

As a general rule, 100 Watts per channel would be a good starting point to choose an amp for the Thiels. If the brand is serious it will correctly specify its product, so you shouldn't find differences of more than 1 o 2 dB in acoustical output between a solid-state amp and a tube amp in this particular case.
My jadis OR with KT90's will drive your speaker. Used, $1500. Also look at the Ming Da tube amp with KT90's/new at $900. The Cayin KT88 "might" work. But I surmise it may be a tad on the soft side. There's not many tube amps used under $1K that will offer "slam". 2 imporant factors that go into makinga great tube amp that has "punch" is the quality of trans and the quality of tubes. Neither of which come cheap. ....There are ss amps under 41K that will give some authority, but as far as fatigue factor and lack of musicality, I couldn't live with it.
good comments mostly. JOLIDA amps used and modified will get it done in that price. 86 db is low tho and even tho amp offers 4 ohm outputs, if your room is large and you like it loud you may need more watts. thiels do like power but i am sure tubes work fine as long as watts are there. $1000 is getting kinda thin for more than 60wpc choices imo. i use 60 wpc unit with 89 db spkrs in larger open sided room and need most of it for big stuff peaks. your room will determine much. closed rooms offer 'free' boost in spl level which can mean a lot when you have to double down power needs at higher levels. imo a watt is a watt until you get clipping. just different sound tween ss and tubes
The reason you hear a lot about tube watts being more effective somehow is due to distortion- tubes make less of the distortions that the human ear finds objectionable- and so *seem* to have a greater percentage of usable power relative to transistors.

The effect is real enough on account of the way our ears work, but if you measure sound pressure levels for the most part watts is watts.

A lot also has to do with the load, in particular tubes in general behave differently from transistors, i.e. they do not double power as impedance decreases. Often though they may *increase* power as impedance increases. Sometimes this gives you more punch on certain box speakers that have a low frequency resonance.

Bottom line is that there are a lot of variables but with many speakers you do get the impression that tube power carries more 'weight'.