Thanks Dcribbs. Haven't had a chance to fire it up yet. No, the treble is not connected to the cut, I just poked the wire through the unused cut control lug to stabilize it. There seems to be a number of posts today in the forum about a PPIMV in this type of circuit, I will try and listen critically to it's performance and report my findings. I'm actually kind of a purist and would just as soon not have one, but my family and neighbors appreciate it ! One thing that a PPIMV allows you to do even if you want to run the amp all out is to find the point where setting the preamp volume results in a mostly clean sound from the preamp with the master set low, then when you crank it you can hear the pure sound of the power tubes distorting ( not really possible in NFB amps.)
Cliff, glad you chimed in. By using the higher values you posted it seems like the effective grid load resistor would be about 330K or higher, does changing the value from the stock value of 220K have an effect on the bias point or anything that would need to be compensated for in some way ? What about going lower, like to a 100K pot - I would actually lean towards using a lower value to reduce the amount of Miller effect but just used 250K in mine to keep it close to the stock grid load values.
2 X EL84 Reverb Rocket
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