mdrew:

In general, if you we're interfacing to different logic or anaog families, the intefaces would not be compatible, so we have to make them so. To interface to a speaker you must provide:
1. low voltage
2. high current

which is opposite fo what a tube provides.

As I posted yesterday:

1. Each has their pros and cons; you just have to decide which you like better, or in my case, experiment with both to find if I think one provides superior audio over the other.

2. Tube amps produce more harmonic distortion, but the type they produce is even order distortion, and is not as harsh-sounding as the odd order distortion transistors produce. Large amounts of even-order distortion (as high as 1-2%) produces little listening fatigue, and can even be relatively pleasant. On the other hand, small amounts of odd-order distortion (less than 0.5%) are audible, even by untrained ears, and make music harder to enjoy.

3. When tramsistors saturate, it's like falling off a cliff, while when a tube saturates, the roll-off is gentle. Tubes use dangerously high supplies, while in general, a transistor doesn't. Tubes have a much shorter life span than transistors. And I think in general, transistor are much cheaper than tubes.

4. So you see, you can choose as many parameters as you like to compare, until someone runs out. Then the parameters have to be rated as to their significance in the application.

5. If you still don't undertstand what I"m tryin to say, say so, and I'll give it another shot.