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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
mapman's avatar
mapman
22,199 posts
 

' 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.
atmasphere's avatar
atmasphere
11,803 posts
 
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.
pubul57
3,712 posts
 
How does this discussion apply to tubes versus SS in preamps?
davemitchell
253 posts
 
Aball's comment about "electron mobility being about a zillion times higher in a vacuum than in doped silicon" reminds me of something Bill Johnson once said about a signal going through a vacuum tube coming out unharmed while a signal going through a semi-conductor gets altered/harmed in various ways.

In practice when listening you can often hear that solid state equipment tends to harden and sharpen transients while closing in the ambient space of live recordings and obscuring the subtle textures of instruments. I assume that this is in part because a signal has to "fight" its way through a solid material in the case of a semi conductor and doesn't do so in a vacuum tube.

I've always intuitively felt that it's because of what Aball was referring to in his post that the sonic advantages of tubes over transistors exist even when the amplifier operates nowhere near clipping and also exist in preamplifier comparisons. IOW, there seem to be some intrinsic advantages to vacuum tubes apart from their distortion behavior.
pubul57
3,712 posts
 
Doesn't the signal have to fight through all that copper wire? To me there is no doubt that tubes sound better, so maybe Bill Johnson's explanation is true, yet it does seem that a signal has a long way to go from needle or laser to drivers.
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