Tube amplifiers and interstage transformers

Based on theory,measurements and the viewpoint of designers of solid state components,tubes should`nt even be a consideration for best sound aspirations.They`re too colored,too much distortion,outdated and measure poorly. Heaven forbid those comptemplating the SET amplifiers(worse of the tube lot).

Charles1dad, I can't agree with that statement, unless you exclude the 'theory,measurements' part of the first sentence.

The human ear is more sensitive to odd-ordered harmonics than just about anything else, as it uses them to determine the volume or loudness of a sound. This is why transistor amps sound bright even though the odd ordered distortion coming out of them is very low. Its just that the odd ordered harmonic distortion coming out of a tube amp is usually a lot lower, which is why they sound smoother.

SETs in particular have an additional quality which is that all forms of distortion they make decreases to unmeasurable at lower power levels (our amps do that too FWIW), something that transistors don't do (below a certain power level, distortion rises with them) and also something that most push-pull tube amps don't do (the traditional thinking being that this is caused by the phase splitter circuit).

IOW, the **theory** says that an SET (or other amplifier with similar abilities) should sound better to the ear. It is unfortunate that so much weight is given to specs on paper that don't mean anything to the human ear, which is the final arbiter. It is possible to create and measure specs that *do* mean something to the ear (IOW have a direct correlation to what we hear) but the industry has zero motivation to do anything like that. So for now, SETs will have to 'measure poorly' as you put it :)

Atmasphere,
I understand and agree with your post.My point is the common argument against tubes is their generally higher distortion and less than impressive measurements. It was my way to encourage alan to rely on his own hearing rather than what some pre conceived prediction or claim what the result will be.Alan says his SET amp is amazing and he reached that conclusion based on his ears.He did it the right way.
Regards,

My experience is similar to Charles1dad's, in that my favorites are SET amps, especially 300B SETs. I've heard superb SETS with interstage transformer, and superb SETs with interstage cap.

Wavelength offers(I think,could be wrong) both IT and non IT versions of their excellent SET
amplifiers.I'd love to hear Gordon Rankin's opinion on how the two options
vary and why.
Regards,

Charles1dad, something that has puzzled me for a long time is the also 'common argument' that triodes are the most linear form of amplification known to man, yet they have more distortion??

The fact is that they don't. Try putting a transistor in a single-ended zero feedback configuration and see what happens :)

The 'common argument' is apparently false, and should be addressed where ever it appears.

We found that by adding feedback to our OTLs we could get the distortion down well below that of conventional transistor amps, but in doing so the amp also took on some of the sterile qualities (read: brighter, less musical) that are hallmarks of amps with feedback. We chose at that point (about 1980) to eschew feedback; if the speaker thus did not allow the amp to sound right on that speaker, the conclusion is that the speaker would never sound right with *any* amplifier! This has limited our market, but the upside is that if a person sets up the amp right its hard to beat.

SETs have a similar 'weakness' (although I regard it as a musical strength) on the same account.

Transistors 'measure better' on account of the fact that the 'measurement' has almost nothing to do with human hearing rules and are simple a method of making the amp look good on paper.