Tube Amp Watts and Quality Electrons. LOL


Have a serious Q. On occasion, I see a serious comment about matching amps and speakers. And the post makes a passing reference to "tube watts" or something to that effect, permitting an inference that a 100 wpc tube amp is somehow not the same as a 100 wpc SS amp. Can someone explain why this distinction is occassionally made. I assume it doesn't have anything to do with the quality of the electrons.

Thanks and Happy Holidays
bifwynne
Tube amps tend to soft clip which allows them to seemingly go louder with less distortion per watt than most SS.
Tube amps generally have higher dynamic headroom, so they should produce more power on peaks without clipping than similarly rated solid state amps. Of course you'd have to look at the dynamic headroom spec on an amp by amp basis.
I love tube equipment and even the tubes themselves, which I collect, but other than what Mapman said, "tube watts" are no different than anyother watt.
Yes there is a current myth that a tube watt is more powerful than an SS watt. Clearly that is silly, physical definitions pertain to audio as much as any other thing.
I do think Mapman nailed it however, if you want an explanation.
To elaborate on Mapman's answer... since tube amps soft clip they can be played at a higher average level since their clipping distortion will not usually destroy speaker drivers (normally tweeters). And many users of tube amps routinely drive them past their clipping points and then contend that "tube watts" are more powerful than "SS watts".

When a transistor amp clips not only is the sound harsher, but the type of distortion produced often will fry tweeters and sometimes other drivers. By the time you hear obvious distortion it is often too late. So greater care must be taken when dealing with the maximum power limits of solid-state amps although I believe some of the Class-D digital amps also clip softly (more like tubes).

With analog solid-state amps it's better to have too much power than too little power so that you never need to drive the amp past its rated power into potentially damaging distortion.
Makes sense guys. Although I've read or heard that if a tube amp is abused beyond the point of all reason, it could oscillate and throw off some damaging signals.

My tube amp's rated output is about 120+ wpc. Honestly, . . . . I can't push it too hard because the SPL hurts my ears.

I assumed the reference to tube power had nothing to do with the quality of the electrons.

Happy Holidays!
I would explain it just as Mapman did above, but Ralph at Atmas-phere has a more complex answer involving current vs. voltage delivery into real world speaker loads. It's on their website and it is well worth reading.
Bifwynn, this article might help, pay attention to the issues of odd ordered harmonic distortion, as that relates directly to your question:

http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
Thanks Ralph. I re-read it . . . again. Your article touches on a point that I raised in another OP. Namely, how can one determine whether a particular speaker was designed to work best with a voltage paradigm amp or a power paradigm amp.

Frankly, the responses in the other OP were not sufficiently informative enough for me to look at a speaker's impedance and phase angle plots and say one way or the other which type of amp would be best suited to drive the speaker in question.

Your article mentioned some specialty speakers that naturally mate well with one type of an amp or another, e.g., electrostats do well with tube amps. What I find confounding is how to make a judgment with respect to the "conventional" bass reflex or acoustic speakers in the middle of the pack.

I am not so proud to admit that through a combination of sheer dumb luck and untrained ears, I think my ARC VS-115 tube amp seems to mate well with my Paradigm S8 v3 fronts. I guess I'm just too dumb to know the difference between sonic swill and audiophile grade sound.

Oh well, I choose to remain blissfully ignorant and happy with what I have.

Happy Holidays to all.

Bruce