Another SOHA lives! Just got it up and running and (no surprise) it sounds great.
Quick question. I built it incorporating Regal's mod from the start. B+ is set to 85v and the tail current set to 2.75 mA per tube section. However, the difference between TB+L and TPL is 22.6V (not 19V per the design website). Is this correct?
Mine is about the same, with this the danger is going below the 19V, a few volt's higher hasn't hurt. Only disclaimer is that if the voltage drop gets too high the upper tansistors could potentilly overheat. With the 50% open top rule you should be fine. I'm guessing that you could lower B+ a few volts and the 22.6V will come down.
You did change R5? Probably a good idea to measure the plate voltage on each section of the tube to make sure they are close, if not you would want to adjust R5, but the tube sections might not be matched perfectly, I don't think its a thing to worry about too much. Just make sure to check these voltages whenever you tube role.
Edited by regal - 5/8/10 at 10:42am