Single ended triode amps have higher THD because they don't resort to negative feedback as a band-aid to fix the inherent nonlinearity of pentodes and transistors. Their distortion is almost entirely low (2nd, 4th) even order distortion, which is much less disturbing to the enjoyment of music than far smaller quantities of higher, (3,5,7 etc) odd order harmonics, which transistor amps produce in more than sufficient quantity to toss the musical baby out with the bath water. Feedback, especially global feedback, obscures and destroys fine detail and thoroughly screws up timing.

As to clipping, transistor amps clip like a ton of bricks - one step over the line, and it's like a waiter dropping a tray stacked high with glassware. Tube amps, and in my experience, SET's in particular, clip much more gently, so an occasional overdoing the volume isn't ghastly. On the other hand, if you're using the right kind of speakers, you won't be clipping the amp in the first place. Kept in the linear part of their response, distortion is extremely low, and fidelity to the musical signal extremely high. That's why you hear/read so often that the most important thing is to get the first watt right. Having a lousy first watt, but hundreds more to back it up is not nearly as satisfying as having a handful of watts, but all of them musically communicative.

As you noted about the Yamaha amp, the best solid state amps do little to offend, but they render the music uninteresting and blah. It's not the amp that has no personality; its personality has stripped the composer and the performers of theirs!

Why do you suppose that every year at CES I find a short tour of the rooms exhibiting solid state gear exhausting, while I linger in (most) of the rooms utilizing tube gear - SET's in particular? It's all of the above combined.

I know this will draw a response of "sure ya like it - ya sells it!", but the fact, as several of you know, is: I got into this nutty business because of what the gear I sell did for my listening enjoyment BEFORE I sold it. I'd be making far more money, but having a lot less fun if I'd stuck to MOR gear and a corporate job.

I think SETs produce more involving sound becuase of the 3 reasons I mentioned in my post above. In a sense, they offer equalization that is preferred by many of us. As a fond SET owner & listener, I am obviously on your & John's side. I just don'think that SETs actually provide better fidelity, in fact I think they provide appreciably worse fidelity...they just SOUND better, in other words they manipulate the signal so it sounds good. For example, audible second order distortion actually makes a signal SOUND "fatter" or weightier....which I persoanlly like....makes the illusion more real! But if the goal is fidelity, then I at least have to go with solid state. IF the goal is enjoyment, then it doesn;t really matter. AS i said, i usually lsiten to my SET 45, which probably measures god awful, but who cares?
-akhilesh

I've yet to hear a solid state amp whose reproduction bears even a passing resemblence to any instrument or any voice, but quite a few SETs that do. So the question is: Fidelity to what?

Good SET amps do not sound fat. I've heard quite a few that do, but remember, I said *good*. Not only good design, but equally important, good quality key parts, particularly iron and power supplies, but also caps, resistors and wire. The ones I listen to regularly sound extremely detailed and precise, without losing the organic sense the sand amps never have.

But, chac un a son gout, which, of course, is French for "to each his own goo."

I'd like to also address something akhilesh said. After akhilesh proposed the question: "Which offers greater "fidelity"? he proclaimed "I think SS amps for sure" I must state that I disagree with this statement 100% I firmly believe that SET's offer the greatest fidelity! According to the Merriam-Webster Collage dictionary Fidelity means:

1 a : the quality or state of being faithful b : accuracy in details : EXACTNESS
2 : the degree to which an electronic device (as a record player, radio, or television) accurately reproduces its effect (as sound or picture)

So if we use #1 as the main meaning, then for true musical fidelity we need to have accuracy in details or "exactness". This is exactly what an SET offers, Musical accuracy. Think about it. Isn't that what everyone who owns an SET says? Just how much it sounds like real music! How can it sound closer to real music and be less accuarte? It CANNOT! Unfortunately, many people look at what the microphone produces. They then compare that signal to another electrical signal and claim how accurately one electronic signal is to the other electronic signal. But our ears are not microphones, they hear completely differently. If you don't believe that statement to be true, please explain why, in any setting, where the music and singers are NOT amplified electrically you'll never hear simbilance (that exaggerated sssss sound at the end of words) yet take that same performance, record it and listen to what the microphone heard and BAM simbilance is now introduced and heard. So either a) It wasn't there in the performance and was later introduced by the mic or b) our ears don't hear like mics do. Either way you look at it, I don't want it added to the music. This is a tough subject and could go on and on. However IMHO, SET's are more accurate than solid state in that they sound more like real music. Solid state is more accurate than an SET when you are comparing one electronic signal to another electronic signal. Just like the second meaning in the dictionary...

Tom Scata (thetubeguy1954)

That's my 2 cents worth.

Tom Scata (thetubeguy1954)

I agree with you that SETs sound great. In fact i just listened to my quasi single driver home brewed setup with my set 45 amp today and really liked it. I still think that SETs sound different from other amps becuase of the 3 reasons in my post above. In fact I know this to be true... i don't just need to take it on faith. However, this does not mean that's bad: otherwise i would not own SETs! I LIKE how they alter the signal. But that they alter the signal can be easily proved.

In terms of what is fidelity: that is a matter of semantics,right? If you define it as something one BELIEVES is accurate, then that is one thng...if it is defined as something measured as accurate, then that is another thing. I think most people would define it as the measurable faitlhful reporoduction of an input signal at hte output...but hey....who cares? It's all semantics.

Also, many of us may be interested to know that anything a SET amp can do CAN be duplicated in an SS amp, in fact Bob Carver did produce his amps in the mid 1990's with 2 outputs: one with low impedance and one with significant impedance (to reduce the damping factor). Tailoring a frequncy curve is not a big deal either. Neither is introducing audible even order distortion. All of these can be introduced in an SS amp. Anything a tube amp can do in terms of amplifying a signal, an SS amp can do.

The good thing with an SS amp, if someone like Bob Carver were to do this again, would be to offer us CHOICES: like, a set of settings for a 300B type effect, another for a 45 type effect, and so on.
That would be really cool!
I await such an amp. Maybe some DIY type here can figure out the circuit for us!

The reason why such a thng is not done, in my opinion, is becuase most amps today are based on commercial chips, and no chip designer will design an amplifier that would conform to the specs of a tube...they'd be laughed out of the business. What we need is a dedicated discrete digital amplifier! But if we have to use those, may as well use tubes. Hence the current state.

PLease do not take this as a criticism of SETs: I LOVE them. 3 out of my 4 amps are SETs. But that they do the three things in my earlier post can be easily ascertained by talking to electrical engineers who are old enoughto have had tube training!
-akhilesh