> Which is better
Depends
> and why-
Because some Speakers distort more on the "out" stroke while others distort more on the "in" stroke. HOWEVER, due to the magnet geometry in most Drivers (from the cheapest dreck to really expensive boutiqe drivers) it is often the "out" stroke that is a little compressed compared to the "in" stroke
> The outward speaker-cone excursion driven by the triode
> going toward saturation or by the triode going toward cutoff?
From the Above, the outward stroke should be driven by the triode going to cutoff. However there is no simple "cut & dried" rule. The best methode to find the correct polarity is by keeping the system polarity the same (polarity switch on Preamp - what do you mean yous doesn't have a polarity switch?) while changing the polarity of the speaker wrt the amp. Using distortion meansurements is the scientific methode. I found that "by ear" I routinely prefer the lower distortion connection.
Sayonara
