Power output of tube amps compared to solid states


I'm having a hard time trying to figure out how tube amp power output relates to solid state power output. I've been looking at the classifieds for tube amps and I see lots of tube amps with 50w or 60w output, but nothing close to the 250w output typical of solid state amps.

So I have no idea what type of tube amp is required for my set up, right now I'm using totem forests with a required power rating of 150w-200w at 8ohms. The bass is so powerful on these that I have the sub crossover set to 40hz.

My question is, are tube amps so efficient that 50w from a tube sounds like 150w from a solid state? Or will 50w output from a tube severely limit how loud I can play my speakers? If so, are tubes usually meant to be driving super-high efficiency speakers?

I had previously tried a tube pre-amp with a solid state power amp (both musical fidelity) and didn't like the results because the imaging suffered greatly, even though the music sounded nicer from a distance. Now I want to try a solid state pre-amp (bryston) with a tube power amp (no idea which brand to look at), but I don't know how much power output I need or if it will even be possible with my speakers. Does anyone know what I would require?
acrossley
Once again, I return to how radical a departure Arthur's posts are when discussing power in amplifiers.

Unfortunately, our posts are again dealing in the traditional means of trying to explain how the watts we measure in a tube amplifier versus a solid state amplifier still correlate in a 1 to 1 ratio. The point is, they don't. Well, at least, not in a useful way of the music / amplifier / loudspeaker relationship. As Arthur gave a glimpse of in such an utterly brilliant way in his initial post, tubes and transistors operate in VASTLY different ways. Like comparing an NFL running back coming through the hole on a play to a distance runner in a 10K event, both moving at 10 mph, living in a world where we use a steady state (linear, quadratic, or even cubic, etc.) measurement to compare them confuses the issue, and only delays us further from the questions and answers that will ultimately solve the puzzle.

Again, this is a question of calculus. Yet we're still attempting to shove it into an arithmetic / algebraic model. Sorry to say, but it just ain't gonna work. Until we come to grips with the fact that we need to operate under a completely different paradigm we're going to be splitting hairs on issues that bring us no closer to understanding.

Grant's question, "What's hotter, 85° in Miami, or 85° in Phoenix?" can get the dialogue back on track. Back in my days as a research chemist / material science engineer, I would use an analogous example in taking the first step in illustrating the difference between temperature and heat. When you open the 350 degree F oven you're baking a cake in, the air and metal oven racks / pans are obviously both at 350 degrees F. And while you are in no peril in putting your bare hand into the oven in contact with 350 degree air, you know not to grab the racks or pans which are at the same 350 degrees F without the protection of an oven mitt or potholder. Without going into the mathematics involved, the metal will transfer that 350 degrees F instantaneously into your flesh, the air does so in a much more gradual manner. In simple terms, that's the difference between temperature and heat.

What I'm getting at is we need to come up with the same type of "temperature versus heat" model when dealing with amplifier power. Then, we'll be capable of satisfying Unsound's relevant question.

The last thing I want to say is that we must also be on guard to not fall into the trap of trying to explain why some folks choose tube amplification as simply a matter of power. Power is but one piece in the puzzle.
I thought Ralph's point was that the choice might be because of the differences in the way tube and SS introduce different types and levels of distortion, not power per se. I do know this about power, I seem to want as little of it as possible, as long as it can make my speakers as loud, fast, and dynamic as I need them to be.

' I do know this about power, I seem to want as little of it as possible, as long as it can make my speakers as loud, fast, and dynamic as I need them to be."

That's a very good way to look at it !

"The last thing I want to say is that we must also be on guard to not fall into the trap of trying to explain why some folks choose tube amplification as simply a matter of power. Power is but one piece in the puzzle."

Good point. And probably not even the most critical one, at least in the simplistic terms usually applied to describe it which typically do not determine that your speakers are as loud fast and dynamic as they can or you need them to be.
Unsound, the point of my post was in fact that all humans do indeed use the exact same perceptual rules- that is what the research (science) has proven. Taste is something else entirely and not on the table here.

As Joe and Arthur point out, timing is everything. What tubes bring to the table is the ability to build a low-distortion amplifier without loop feedback. With no loop feedback, time-domain distortions are 100% eliminated. With feedback, time-domain distortions become the name of the game.