Tube amplifiers and interstage transformers

Thanks a Atmasphere for his technical explanation of his experiences with transformers in amplifier design.

And yes Charles1dad, I will have to listen for myself and compare.

I have listened to some amplifiers that have ITs and I liked their sound. Mostly, I listened to them not in a proper listening session but in a demo room.

Best way to get out of doubt will be to get me one and live with it for sometime.

Alan,
That`s good to know and the right direction to take.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components,tubes should`nt even be a consideration for best sound aspirations.They`re too colored,too much distortion,outdated and measure poorly.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).Funny thing is with all this logic, SET are to people like me the most realistic and natural of any type of topology I`ve heard.The very best sounding system I heard in Las Vegas a few weeks ago(CES and T.H.E. SHOW) was the Absolare-Rockport at the Flamingo Hotel.

The Absolare Passion was a PSET with 845 tubes(and an interstage transformer!), it was just stunning good and utterly realistic and sublime. Other 'exceptional' systems in comparison came off as only very good "Hifi". You just have to listen and trust your ears and spontaneous reactions.I`m sure no way, no how this amplifier has bandwidth or measurements that would compete with many other amps I heard(it`s SET, how could it?). I believe what matters most for excellent sound are qualities we don`t/can`t measure.Alan, you say your SET sounds amazing, I believe you.

Regards,

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components,tubes should`nt even be a consideration for best sound aspirations.They`re too colored,too much distortion,outdated and measure poorly.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.