new tung sol kt 120

Folks, beware that the KT-120 draws 1.8 Amps heater current per tube, as compared to the KT88 1.6A spec.
A stereo push-pull amp with four KT-120 tubes will draw 800 additional milliamps from the heater winding. The amplifier's power transformer will run hot and possibly fail in the long run.

I think this may be an excellent tube for a new design buit around its strengths.

IMO one can safely try KT-120s only on conservatively designed tube amps with over-specified power transformers that run cool and that use self-bias / cathode bias.

Fixed bias amplifiers need to be modified before one installs KT-120s, so this rules out most USA-made muscle push-pull amps.
I hope this helps.

Flyfish, yes, your amp has fixed bias, because it has bias trimpots. Actually this is a misnomer, because it is adjustable!!

The non-adjustable bias method is called self-bias or cathode bias, usually performed by a resistor in series with the power tube cathode.