Re: Old amp with wierd driver xfrmr setup - help please

10/12/2003 8:53 PM

Ray Ivers

Re: Old amp with wierd driver xfrmr setup - help please Henry,     My advice would be to lose the transformer PI (if it's still good I would save it, though) and set up the first 6SL7 stage with a 150K Rp and 2.2K Rk bypassed with a 10 uF cap, then a .01 uF cap to the 500K volume control, with the wiper connected thru another .01 uF cap to the grid of the second 6SL7 stage. This grid should have a 220K resistor to ground and a 470K resistor to B+, with a 68K Rp and Rk. From the plate and cathode of the second 6SL7 stage connect a .01 uF cap to each 6V6 grid thru a 2.2K grid stopper, and a 470K from each 6V6 grid to ground.     If nothing is wrong with the present components you should definitely be able to hear this setup over your unplugged guitar. You may want to further tweak these component values, at this point I'm just trying to get you some power output.     Ray