This just in!
“The higher harmonics, above the 7th, give the tone "edge" or "bite." The basic cause of the difference in tube and transistor sound is the weighting of harmonic distortion in the amplifier’s overload region (the italics are mine). Transistor amplifiers exhibit a strong component of 3rd harmonic distortion when driven into overload.”
Since there are so many sources of distortion one has a very tough road to hoe to try attribute any distortion he hears to the particular source or sources. Some things are easier than others, for example mechanical feedback and clipping.
“The higher harmonics, above the 7th, give the tone "edge" or "bite." The basic cause of the difference in tube and transistor sound is the weighting of harmonic distortion in the amplifier’s overload region (the italics are mine). Transistor amplifiers exhibit a strong component of 3rd harmonic distortion when driven into overload.”
Since there are so many sources of distortion one has a very tough road to hoe to try attribute any distortion he hears to the particular source or sources. Some things are easier than others, for example mechanical feedback and clipping.

