I like the amp a lot. I'd suggest you not skimp on OPT or power supply. I've made a fair amount of revisions and mods, including stereo chassis and SS rectifier. I don't know that made a positive difference, I'm just more comfortable with that style build. I think the three biggest improvements (to my ear) are:
1: Filament snubbers for all tubes (no hum for all practical purpose thru 97 db speakers
2: 6DN7 input driver. Plate resister 90K and cathode resister something like 1.23K. IIRC plate voltage approx 150 volts and 4.5 volts at cathode. CF about 150 volts to ground.
3: Inexpensive grid chokes. This is the most "off the wall" experimental change. Thats what makes me happiest that it worked and worked well. Two of the $11, 150H 8ma filter chokes in series per channel. Isolate from chassis. Ground body to chassis through a .47uf poly cap. Give it 50+ hours to break in. I ran it in parallel with the grid resister.I would certainly recommend you build per schematic first and then play around. Oh yeah, have lots of fun with it.
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