Tubes? Transistors? Which are better?

Output impedance isn't theory at all. It perfectly describes the power amp's ability to control the cone motion of a dynamic speaker, which is what I was talking about. I suspect I would like the sound of your system, Redkiwi, but it's possible I could improve on it...Not to diminish the time you spent evaluating, but I forget, do you use room treatments?

I do use room treatments Carl, but one of my rooms (I run two systems) is problemmatic and hard to deal with (the main problems being squareness 24'*26', and hard floor). But with the narrow vertical dispersion of Martin-Logans I get very good results sitting about 9 feet away in this room. By the way, I was not referring to your comments on output impedence in my earlier post, but to the seemingly generally accepted wisdom of tube pre with ss amp. My fault for dropping into the conversation out of context. I switched from ss to tube power amps for a simple reason. When I went to live concerts I was always struck by a kind of beauty in mid-range instruments (particularly voices), that did not seem to be present in my recordings. When I heard my current tube amps - I recognised the beauty right away - and knew it to be real, and not a coloration. The fact that the amps gave me better bass than the ss amps was an unexpected bonus. The problem of course is that I may never know whether the same thing might have been achieved by the change of some other component.

As long as all of us are touting our favorite poison here, I must confess, I am a tube guy all the way. One main reason that tubes sound more musical is that they don't "switch" on and off like transistors do, and when tube designs produce distortion (ALL amps have distortion) the tubes do it in "even" order harmonics, just like music does. Transistors do distortion in "odd" order and also contribute IM distortion in the process. This can sound like detail, but I find is stressful and distracting, and less convincing than the presentation of tubes.

Try Jeff Rowland with Michael Green Designs Chameleon loudspeakers,Albert.Tell me later if it is not convincing.

I have heard Jeff Rowland's amps, and for transistors they are one of the three best I have ever heard. The others being Griphon from Sweden, and FM Acoustics from Switzerland. I still prefer tubes, for the same reason I stated before. It after all, is a matter of choice, and I certainly understand why you like what you do.