I am in the process of doing two studies aimed at understanding some details of sound perception, but the question that you ask - LD versus HD seems so obviuos to me that I am not too interested in doing it. Once you heard a HD CD system properly setup I think that you too would also agree that such a test is not really needed.

If the question that you are asking is what HD is optimal, 45°, 60°, 90° etc. then I can agree that would be an interesting test. But to ask if 90° is better than 360°, I think thats a no brainer.

-akhilesh

There is also the matter of types of distortion. Tube amps generate mostly second and third harmomnics. Class A tube amps generate mostly second, which most agree sounds more natural than say seventh. Class AB tube amps generate mostly third, which is still fairly low. When the amp nears clipping, the output reduces gain as it approaches the peak, sort of like a built-in compressor. So the edges are rounded and sometimes it is hard to hear the onset of clipping with a tube amp. You notice it when you really press into clipping, but the start is barely noticeable. So I think these are the things that attract people to tubes. The beauty and the character.

I've grown to really enjoy nice tube amps. I love the looks and the sound. But if pay attention only to the music and the amp is kept well below clipping, a nice solid state amp is wonderful. I have some excellent solid state amps that produce very pure sound and a lot of power, more than I ever could expect from tubes. So that is important to me also.

You'll notice that many of the same people that are die hard SET lovers have been attracted to the very inexpensive digital amps. These are opposite ends of the technology spectrum, so I think some just like to be on the edge. They like what is unique. They are probably attracted to sound qualities too, but I think the novelty aspect cannot be overlooked.

And there's the aesthetics too. When a piece of equipment is like art, the beauty will capture you. There can be a beauty in simplicity, a plain black chassis with no controls. But when you see a chrome chassis with black accents and tubes glowing, the amplifier becomes art in light. I'm sure that grabs as many tube converts as anything else. If it looks like that and sounds good too, it has a very sensuous allure.

• "A Taste of Tubes"

In the past I've run a tub pre-amp with a sand power amp - the result is the "tube sound" without the high $/watt penalty.

• Tubes versus Transistors

http://www.pcabx.com/technical/index.htm

Akhilesh was telling me he found a webpage that had wav files of distortion. I'll bet the http://www.pcavtech.com/soundcards/techtalk/dist_sound/index.htm page was it. The other page, http://www.pcabx.com/technical/index.htm is very good too.