W4JO Jim (SK) owned and used this amp extensively. When he upgraded to autotuning amps we decided it needed to come live at my shack. (Jim always had an easy payment plan). It is one of the smoothest tuning amps I've ever used, and on air reports have been great.
It uses twin Eimac 3-500Z tubes in the grounded-grid configuration, and Jim had a spare set of tubes as well. Even though it's an older amp, it has everything you'd want in a tube amp, and is still well respected.