Tube Watts vs. Solid State Watts - Any credence?

10-10-15: Ebm
Wow thats a tough one i was up all night thinking about that!!

EBM, I'd like a different snidy punch-line. I've laughed at this one one too many times! Search your sarcastic brain for a new snidy remark. Thanks.

Secondly, how can low powered tube amps sound so much better with some speakers that have amp recommendations much higher? Very few tubes get over 100 watts, yet are very prevalent even on some inefficient speakers. Any thoughts? Just trying to learn more.
Djfst

Atmasphere explained this quite clearly in his post above. Did you miss it?
it's the distortion characteristic of tubes amps - when they're overdriven a little the distortion is more pleasing to the ear than a s.s amp that is overdriven the same amount.

I know tubes have there own characteristics, but besides that, from a power standpoint, would it be better to go to KT120s to get more power to my speakers? Would the difference in wattage moving from EL34s to KT120s (15 watts increase in ultra linear, 5 watt increase in triode), be beneficial or even perceptible to my ears? Would this be better for the performance of the speaker, or at least the health of the speaker?
Djfst

in the end it really depends on what kind of sonics you prefer.
Tube amps using ultra-linear mode of operation use a lot of global negative feedback to generate a higher wattage. These sort of amps have a very robust sound & trend to sound more like s.s. amps. And, behaviour-wise they also behave like constant-voltage sources (which most s.s. amps can be characterized). I've found that ultra-linear tube amps had more bass punch but their mids & highs do not have the delicacy that is often associated with tubes.
Operating an EL34 in triode mode would be operating this tube in as linear a mode as is possible. Remember the EL34 is a pentode tube but in triode mode it operates like a tube with 3 units (sorry I could not think of a better word at this time!) - anode, cathode & 1 screen. You get much less wattage (as you have stated) but you get a beautiful tube sound that trends towards the type you hear from more traditional triode tubes such as 300B, 2A3, PX25, etc. At one point in time i used to own an AES Sixpac that had 6 EL34 per chassis & output 60W/ch in triode mode. It was a very addictive & beautiful sound. That amp drove my then-speakers with plenty of power - didnt have the bombastic bass of a s.s. amp but i did not care as I got much more from that amp that compensated for a less bass response. When I changed my speakers that amp had to go. Personally, I'd go for linearity hence triode mode. But like I wrote before - you might like you music delivered differently.....

10-09-15: Djfst
So a followup question - if 2 amps both have 140 watts, why ever buy the more expensive amp if you are paying for wattage? Most have indicated quantity of wattage, but can the quality of wattage be better in some amps than others?

The more expensive amp has a more robust power supply which most probably allows that power amp to double down with each halving of the load impedance. This means that the more expensive amp also has more current delivery capability which in turn means that it can power hard-to-drive speakers far more easily than the less expensive amp.
This is based on the assumption the you are not comparing 2 very disparate brands i.e. both amps are of brands that have similar reputation & command similar prices in the marketplace.

10-10-15: Inna
I don't remember where but once I read that someone was comparing the sound of 100 wt Gryphon with 600 wt Krell, both transistor amps. Same speakers,forgot what that was. Besides sounding a lot better in every respect, Gryphon also sounded more powerful. Dynamic speakers, this I remember.
What are the possible explanations?

the above is an explanation for your question Inna. In this specific case the Gryphon doubles down all the way to 1 Ohms. One of the rather rare s.s. amps in the market & very expensive. My friend used to own the Antilleon Signature which was a 100W/ch amp but was 800W/ch into 1 Ohms. Beuatifully built amp - like a tank & almost no speaker could ruffle its feathers (but don't hook an ESL to this amp as it was not meant to drive an ESL).
Current delivery into a speaker load is very important esp. when it comes to hard-to-drive speakers (which are characterized by having wild impedance & phase swings).

"Currently am running eight EL34's tubes in a primaluna HP integrated amp to Sonus Faber Olympica III speakers"

This is a coincidence. The guy who bought the Krell FPB 200c from me is using Sonus Faber Cremona (the originals) an erstwhile predecessor of your Olympica 3's with likely the same Prima Luna integrated. He muttered something about 40 watts. He said there wasn't enough juice to push the sound out of his speakers. A few hours with the Krell in his setup, he calls me up and thanks me for the best thing he has ever done to his speakers as they really sang like they never did before. I believe Franco Serblin voiced the Stardivari's with older FPB Krells. I understand the new Sonus Faber's are more sensitive. I heard them with ARC Ref electronics and they left me cold compared to the older Sonus Faber sound. I guess the last Sonus Fabers I liked were the Stradivari's and the Guarneri Memento's (not heard the Evo's)

Not doubting what you hear in your system but I guess different strokes for different folks.

Wow thats a tough one i was up all night thinking about that!!

It's all about the sound of your amp not the juice. i just went back to a tubed separates set up, trading in a 3 month old McIntosh MAC6700 solid state receiver for an MC275 tube amplifier. Since I rarely drove the receiver past 30 watts, and it was "voiced" to emulate the McIntosh tube "sound" I figured why use solid state in the first place?
(MC275, Audio Research LS3 SS preamp, Von Schweikert VR 3 speakers)
The 275 sounds true, with an openness the solid state appeared to muffle. I don't believe I have ever clipped any one of my amps over the years since I listen at fairly moderate levels. If I return to solid state I will go back to Pass Labs

A practical question out of all of this is power tube choice in the same amp. Currently am running eight EL34's tubes in a primaluna HP integrated amp to Sonus Faber Olympica III speakers. The Sonus Fabers are 91db, 4 ohms, and recommended amplification of 50-300 watts.

Tube choices in the amp are as follows:

ULTRALINEAR MODE:
85 watts x 2 (KT120)
73 watts x 2 (KT88)
70 watts x 2 (EL34)

TRIODE MODE:
45 watts (KT120)
42 watts (KT88)
40 watts (EL34)

I know tubes have there own characteristics, but besides that, from a power standpoint, would it be better to go to KT120s to get more power to my speakers? Would the difference in wattage moving from EL34s to KT120s (15 watts increase in ultra linear, 5 watt increase in triode), be beneficial or even perceptible to my ears? Would this be better for the performance of the speaker, or at least the health of the speaker?

Uh - a watt is a watt ...it is a unit of measure there is no difference by virtue of the device that produces it.

Now frequency characteristics, load interactions and clipping or distortion characteristics- that is different.

I don't remember where but once I read that someone was comparing the sound of 100 wt Gryphon with 600 wt Krell, both transistor amps. Same speakers,forgot what that was. Besides sounding a lot better in every respect, Gryphon also sounded more powerful. Dynamic speakers, this I remember.
What are the possible explanations?

High end audio is definitely tricky. For example, I'm running a Primaluna Dialogue HP Integrated Amp with EL34 tubes to Sonus Faber Olympica III Speakers which are 91db efficient and are 4ohms rated according to specs. The Primaluna has 4ohm taps and 8ohm taps, and the 4ohm speakers sound far better on the 8ohm taps.

It might actually be true that: "...a 70 Watt tube amp provides more power than a 140 Watt solid stat amp." if used on speakers with an impedance of over 16 Ohms.
But, selecting an amp involves more than just this issue, there are other variables to consider.

Do

That's like saying why ever buy the more expensive tv if they are both 52 inch. Or the more expensive car if both have same horsepower engine.

With technology no single spec ever tells the whole story. In fact specs as a whole cannot. No two amps are exactly the same. There many differences some subtle and some profound. Quality being just one general category. Same as with any complex piece of technology.

I was just about to ask the same question.

I moved from Dynaudio's at 86 dB to Vienna Acoustics Kiss at 89 dB, both into 4 ohms and am looking to change my amp from a Krell FPB 200c to a tube amp - either a Conrad Johnson LP 125 sa or a Cary CAD 120 S Mk 2 both at 120 plus watts vs the high current Krell which doubles down into 400 watts.

Will I get sufficient watts from either of the tube designs? The manufacturer recommends 50-180 watts and received wisdom seems to be that the speakers respond better to solid state watts (what does that mean)?

I am using a pair of 40w EL34 monos driving a pair of 87dB efficient bookshelves full range with a sub crossed over low just to augment what my speakers can't reproduce and it rocks....plenty of power in my 15 x 17 x 9 room

I had previously used a McCormack DNA 125 which was a great amp no doubt but I don't think I even came close to it's full power even at louder volumes

So a followup question - if 2 amps both have 140 watts, why ever buy the more expensive amp if you are paying for wattage? Most have indicated quantity of wattage, but can the quality of wattage be better in some amps than others? Secondly, how can low powered tube amps sound so much better with some speakers that have amp recommendations much higher? Very few tubes get over 100 watts, yet are very prevalent even on some inefficient speakers. Any thoughts? Just trying to learn more.

The effect has to do with the distortion of the amplifier.

Since a transistor amp clips harshly, its obvious when it happens. A tube amp has a soft clipping characteristic (which can be modified somewhat depending on how feedback is used with the amp). So even though the amp is overloading, as it enters clipping it won't **sound** like it- and as you push it harder, the higher ordered harmonics become more abundant. Since the human ear uses those harmonics to figure out how loud a sound is, their presence will make the amp sound louder than it really is. This works until the clipping is so severe that the amp starts to break up and makes hard clipping like a transistor amp.

If you place a sound pressure level meter in the room, the phenomena will be revealed, which is to say that watts is watts.

For example, a 70 watt tube amp provides more power than a 140 watt solid state amp. Is there any credence to this or just sales talk and misguided listeners?

it's just sales talk & misguided listeners. No credence to this statement. As Mapman & many others before have written: a watt is a watt tube or solid-state.
Ralph Karsten of Atma-sphere has written a paper on power amplifier paradigms:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Kijanki is very right---a hard clipping amp is dangerous to the health of your tweeters. I had a low-powered SS amp burn out a dome tweeter in the blink of an eye when it clipped, and the volume was pretty low.

Most tube amps soft clip so effects of not enough power are
not as unpleasant. Other than that, a watt is a watt.
What's different is how far a watt can be made to go. Soft
clipping helps. Limited bass extension does as well. These
are things that can help make a speaker seem more
"efficient". You need exponentially more power to deliver
a lower frequency at a certain volume level. That's
physics....basically how things work no matter what anyone
might claim. That's why a table radio with just a few
watts and limited bass extension might sound clean within
its limitations at a louder volume.

The difference in perceived loudness between 70W and 140W amplifier is only 22%. Tube amps, when overdriven tend to produce "soft clipping" (softer/gradual overdive transition), while SS amp just chops off the peaks producing a lot of unpleasant sounding odd order harmonics.

Some SS amp were designed to soft clip, including my class D Rowland 102 (and some NADs) but most of them don't. Overdriving SS amp is not only much more noticeable, but can also damage tweeters because of excessive energy in high frequency harmonics.