WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
I used to build all of my bigger (>60W) PP amplifiers using global feedback fed to the inverting input of an LTP input stage.. Worked just fine.
Designed a 0 global feedback PP 300B amplifier that was published in VTV with an LTP as input stage with a balanced input option. Built a similar stereo 300B PP amplifier commercially, no global feedback with an LTP input normally configured for a single ended input, a balanced option was available, but no one requested it.
That's about what I'm looking for. PP power amp in the 40-60W range (instrument app.). After posting here I thought about the old Fender stand alone reverb unit which basically does what I'm interested in. Thanks much.