Oh how I wish Class D amps ...

Mapman, if a tube amplifier is fully-differential from input to output, it will not have even-ordered harmonics- they will be canceled at every stage throughout the amplifier. The even orders show up when part of the tube amp is single-ended. With most tube amps, that is the input voltage amplifier.

So when Dob was wondering why our amps don't seem to have any 2nd order coloration, that is why. IOW, its not a universal thing that tubes inherently have that coloration! You can get transistors to do that too if you run them single-ended.

Atmas,

Thanks for that clarification on tube amps.

Class D amps are not tube amps though so I am not sure why Spectron groups tube and other Class D amps together in any technical discussion other than to assert that their products are superior to both for similar reasons, which does not seem like a viable argument. There are many factors that go into end sound quality as has been discussed ad infinitum here and elsewhere. So pointing out a single technical characteristic and attributing good sound or not to that alone does not carry much weight for me, especially when I ears tell me I should not care.

It is a typical marketing ploy though, so Spectron is not uniquely guilty of anything new there. It is what it is.

Athmasphere,

Thank you, thank, thank you for explanation !!!

This is EXACTLY the same philosophy of use Spectron in fully balanced configuration: cancelation of all distortions: even, odd, blue and read !!!

Per Simon Thacher of Spectron the KEY lies in the part quality - pure and simple.

Simon also is saying, and I am not sure if you will agree with him, that if we cancel distortions or actually greatly diminish them then the SOURCE of distortion is immaterial: it could be tube amp or transistor amp or class A or class WYZ - whatever; distortions are gone and so specific sonic characteristics of these amps also greatly diminished... and indeed, balanced monoblock Spectrons sound almost as good as Joule-Electra, I am in love with..

Incidently, Joule-Electra pre- and power amps may or may not have balanced input and/or output but internal processing is balanced ALSO (they use phase splitter).

Thank you again - I saw different pieces but could not put them together....

Dob and Athmasphere, your amps sound clean. So do the others. I have used a number of AB amps, and though the builder of such amps will say they have canceled out all distortion, they don't hold a candle to the clarity my ICE amps have.

I found this interesting quote muttered by John Atkinson:

"It's not that they (class D) measure badly, it's because I have to be extremely careful to ensure that I don't end up measuring my test equipment's limitations."

Oh, now that is quite a telling confession.

"... they don't hold a candle to the clarity my ICE amps have. "

I am sure you are absolutely correct. No one in his right mind would challange your assessment of your own amplifiers.

Athmasphere was just helping me understand why the best tube amps have near zero distortions level. The same philosophy (approach), he described is that of many other companies. I mentioned Spectron statement that based on PUBLISHED measurments distortions are...distortion are...distortions and bad for you...even pleasant for ears as even-order harmonics or ear-piercing odd-order ones.

It has nothing to do with fantastic qulaity of yours and everybody else amplifiers. Somebody mentioned above that sound quality is a function of many parameters and distortions (type and amount) is only one of them. Nothing more.

Peace.