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
Yes, a watt is a watt is a watt but the rail voltages on tube amps are much higher. In my expereience comparing tube wattage to solid state wattage it is about a 2 to 1 ratio.
1 SS watt = 2+ tube watts in my experience in terms of filling a space with sound.
I have some experience with Thiel loudspeakers - mainly with Cs 2.4. I believe that the idea to drive Thiels with tube amp is generally very bad idea. Very, very bad idea. Thiels are well known as very power hungry speakers, which provide the quality of reproduction that they are known for only when they are connected to the amp with powerful output stage. You might look at something like BAT VK-150 or similar but generally you should go for SS - and very poweful SS ...
The sound level that can be produced by a tiny amount of power was made clear to me when my son hooked up a KLH5 low efficiency speaker to his clock radio. The KLH5 was a sealed 3-way system, and the clock radio was probably good for 500 milliwatts. I told him it wouldn't work, but it did, and surprisingly well.
In my experience tubes and Thiels are a very good match you just need enough tube power to drive them and there are many factors that determine power requirements. Thiels are a demanding load but not difficult one because of the relatively low but flat impedence curve.

Chuck