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previous: Henry Ramsey Bingo, that's what I was told at t... -- 10/12/2003 6:56 PM View Thread

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
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.  

Henry Ramsey Well, on further testing the thing ... -- 10/12/2003 9:57 PM