Tubes vs. solid state.

Paulfolbrecht, yes, General Electric proved that humans use the 5th 7th and 9th harmonics as a means to determine the volume of a sound back in the mid-60s.

So how this relates to the TvsSS debate: The issue centers around feedback- by adding feedback to a tube amp you can make it sound 'solid state' on account of the chaotic harmonic noise floor. I believe the sound of 'solid state' is not so much that of transistors, rather that of a transistor amplifier that has a lot of feedback. Nelson Pass is a good example of someone making transistor amps that don't sound 'solid state'. Many of his designs use no feedback.

For decades, triodes have been known as the most linear form of amplification (at least as far as the specs of triodes appear on paper). The trick it to use the triodes in a way that they will not make distortion **without** also using feedback. IMO/IME this is the primary advantage of tubes- that you can do such a thing in a way that to me seems easier than with transistors.

People such as Nelson Pass are eroding that advantage; I think ultimately though that too few designers are trying to figure out how to crack the nut without feedback. We now know from Norman Crowhurst (55 years ago), General Electric (45 years ago) and the proofs of Chaos Theory (mid 80s to present) that feedback simply does not work- and won't until an amplifier without a propagation delay is somehow devised.

Olesonmd's examples bear this out- the amplifiers used in his examples all use feedback and so have more errors in common with each other and less in common with real music, regardless of being tube or transistor.

Anyone who claims that the "overall superior performance" of solid-state has been "scientifically proven" has no understanding of the real issues.

I guess it was proven in the 70s when we had those wonderful solid-state amplifiers with their amazing THD measurements.

A-S, of course I pretty much agree with your thoughts. (And I do not have your engineering knowledge.)

I think most agree Pass amps sound great but not really like [very good] tube amps.. dimensionality does seem to be a bit flatter for one thing. Of course they have advantages too. It is just a different sound - one with no real weaknesses I would say.

There are quite a few SS amps now that manage to avoid nearly everything in the telltale SS signature.

Amazing and very interesting discussion. Please keep in mind that there are several lines of thought regarding amplifier design. 1) the amplifier is designed to drive specific loads, 2) look like an open circuit (impedance wise) so that it does not load down other electronics feeding it or 3) is specifically designed to accurately reproduce and amplify the input signal. If you design an amplifier to accurately reproduce and amplify the input signal without taking into account what loads it must drive, it will oscillate, blow up or just not work correctly. There is a difficult engineering dance that engineers must adhere to in amplifier design and also, compromises that must be taken in any amplifier design. The point that I was trying to make earlier and in other posts is that one must know what instruments and vocals really sound like first in order to understand if the equipment is designed correctly and working correctly. If it sounds as if you are listening to speakers, then, something is wrong. If you can't tell where the artist are on the stage, how deep the stage is etc. then either something is wrong or the music was recorded badly and maybe there wasn't a stage at all or instruments, but electronic instruments only. You never know what was recorded and how. It is hard to judge. I am not an advocate of classical, live unamplified, amplified, jazz, rock, etc. I love any music that is good. However, understand that most kids have no clue that they are listening to drum machines, electronic instruments instead of real instruments, etc. So, when they hear your system, they may not appreciate it because they have a bad point of reference to begin with. A short story. years ago, I took my daughter to a concert to hear (see) Roberta Flack. Outstanding in person, recordings, don't sound nearly as good as live. you could hear deep sighs and breaths and gasps from the crowd as she played piano and sang. That is when my yound daughter learned what signing really was. Remember, we are constantly trying to reproduce something that was recorded. 1) was the recording done correctly? 2) the mixing? 3) was the replay equipment and cables designed and build correctly? All of these inpact the ultimate sound. Did the artist step out of your speakers and can you see the room, instruments and maybe her face? if so, you are there. If not, then we aren't there yet. But, you got to admit, it is fun getting there.

Enjoy

Minorl, sounds to me as if you are saying something that I've been harping on a lot- that the playback system has to take into account the rules of human hearing/perception and obey those rules. Designing to specs on a piece of paper doesn't do it (unless those specs take the ear into account, which, these days, they don't).