I really like the sound.
>Let's assume for a moment that the circuit sounds much better
>without the degeneration, even though the measurements are basically
>the same. Then you would still have the question of what is causing
>the sonic difference. Is it the degeneration, or the presence of the
>resistors?
It sounded sterile at first. Thru experimenting and listening
tests, I found that placing a 10 ohm carbon comp resistor in the
cathode of the output tube warmed it up. This caused about 1.4v
worth of bias and some tiny amount of feedback (or degeneration).
Increasing the value of the same type resistor caused too much of
the warmth. I didn't try other resistor types.
I have an HP-334 distortion analyzer. It isn't in calibration,
but it can measure differences pretty well. There were no measureable
differences between with the carbon comp and without (not that
they weren't there - I couldn't measure them :)
The amp is *really* sensitive to the components used in it, more
sensitive then other amps I've built. My belief is that it is the
sound of the resistor itself that is responsible for the sound
change - How's that for subjective effects!