`  :Many (who HAVE heard good high end systems of BOTH kinds, including many HiFi journalists and other very widely informed and experienced commentators) hold the opinion that some good tube amps are much better able to capture the atmosphere, life and naturalness of music (esp accoustically recorded music) better than silicon amps - regardless of what the measured performance comparision is. Some DH-SETs soud amazingly good even at ? 1% THD. Some transistor amps that measure at <0.002% sound crap. Unless and until you can explain this, and present some other measurement that actuyally do give a correlated indication of sonic ``acceptability`` - many high end audiophiles would suggest that you pay only passing attention to measurements. Your ears are much more sensitive. And to a music lover, more important  :FYI, I have also heard (indeed owned) extremely highly regarded (not to mention expensive) transistor amps, including from KRELL (KMA-100 class A monioblocks for the record). Most people would accept KRELL as being a reasonably good representative of breed  - and equally I have heard them blown into last week by tube amps. :Well, ideally of course we want no distortion, we want perfection. Which kinds of rules out class B immediately. Sadly that takes will it a large chunk of mainstream consumer electronics. If someone WANTs some odd  order or aharmonic distortion, thats a matter for them, but in that case I think we have nothing more to discuss with them about high end audio - they need help, and possible a hearing aid :Whoever claimed they were superior ? I have throughout gone out of my way to cite the disadvantages as well as the advantages of both, and also to note that the majority of tube amps use NFB as well as (almost all) transistor ones.#   ::Didnt say you hadnt.   :::Actually you have. repeatedly. ;-)  :However such a statement as you make above is simply prejudice (not least as you admit you havent heard a decent tube amp in ages). Newer does not automatically equate to better. There are very many people who would agree with that statement (many of them also having never taken the time to actually try the alternatives they so enthusiastically condem). There are however also many people who HAVE heard who will say that transistors amps are not inherently superior. Wise people will probably find good examples and merits in both.   ::I wasnt aware of making any prejudiced statement. Which one?   :::so many to choose from ...  :But the fact remains that NFB is not perfect either (I strongly recommend you read Colloms article referenced on this page), and at the high end there is a significant tendency to have greater open loop linearity and less NFB, with a significant slice of products using no NFB at all. The later being an option that transistors dont really give except in a very very few niche examples (refer my comments about Nelson Pass, below)  ::Yes it rules out class B if you prefer class A type distortion to crossover dist.   :::This is facile/misleading. The whole point is that class A gives dramatically less (asymptotic to zero in fact), and sonically ``not so bad``  distortion under small signal conditions, whereas class B gives exponentially increasing distortion of a very unpleasant kind under the same conditions. Anyone who would ``choose`` large amounts of unpleasant distortion over lesser amounts of less objectionable distortion imho should abandon any pretensions of listening to HiFi, which is after all about ``high fidelity``. NB this is not saying class B has no place or is ``inferior``. It is much more efficient and as such is the only viable approach for high power on a budget etc etc etc. But lets not delude anyone that from a distortion perspective it is on a par and ``its a matter of choice which kind of distortion you prefer``. Puh lease  ::I respect your pov! But its just your pov    :::never claimed it was anything other than a POV, although there are very MANY tube enthusiasts who share it (and can give good reasons why, bot bsed on theory and what their ears tell them when they listen, and most of them are in addition to yube enthisiasts (thet they have BECOME) more generally Hifi and music enthusiasts, and they usually have very wide experience of listening to a huge range of equipment, of all types and all price levels. Of course there are also people with a pro silicon POV. I think it is interesting that the majority of strongly anti tube POVs seem to come from people with little or no actual experience of them.   :Whoever said other