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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
unsound
7,329 posts
 
Duke, thanks, that all appears to make sense to me. I do have further questions, but I believe they are not germane to this thread.
koegz
317 posts
 
Unsound; I think you are referring to the GE study in the 60's. I found the paper to be very imformative AND unbias, as you seem not to be. I have been a SS person my entire 53+ yrs. I will say after hearing a properly set up tube system I desided to sell my SS and give it a try. There are no absolutes only trade offs. BUT there is no denying tubes. that would be like denying jitter in cd's just because they are only 1's and 0's. Oh they did!
unsound
7,329 posts
 
Koegs, actually I was referring to more recent post by Atmasphere, where he offered this link:
http://paulspeltz.com/tomcik/index.html
I don't believe there is any bias in this report.
It is interesting that in the link Atmasphere offers, the writer suggests using feedback to achieve critical damping factor, when Atmasphere has gone on record regarding his objection to the use of negative feedback.
pubul57
3,712 posts
 
Speaking of damping, don't drivers in speakers have their own damping where some drivers need more damping and others less, so that they don't need, or want, to much damping from an amp. For instance, my Merlins are said to have critically damped (whatever that means) damping and therefore work best with tubes and tended in the past to not do so well with SS as they overdamped the speaker.
shadorne's avatar
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shadorne
7,477 posts
 
For instance, my Merlins are said to have critically damped (whatever that means)

Critically damped means a Q of 0.707. It is a function of the driver Qes (electrical Q) and Qms (Mechanical Q) and the acoustic damping from the box (air pressure).

A design that is overall critically damped is the fastest design that returns to the rest or "zero" position without overshooting the rest position when the power is removed.
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