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previous: dave mcculloch got an idea this afternoon, -- 4/30/2003 10:40 PM View Thread

Re: ef86 preamp...

5/1/2003 1:14 PM
MattRe: ef86 preamp...
I built a Plexi type preamp but the Normal (dark) channel was an EF86 and the Bright channel was a paralleled 12AX7. So using only the Normal channel, it was the EF86 followed by the usual Plexi second stage then CF then tone stack. It's been a while so I don't remember the values/methods I used. I'm pretty sure I used some methods suggested by kg but if I try to elaborate on what I did, I'll probably get it wrong (IIRC it was voltage divider for the screen with a connection to the cathode thru a cap, or something like that :)). I'll check tonight and post it tomorrow. The PI in this amp was an attempt to "optimize" a 12AT7 (much lower plate loads and lower cathode resistor, again IIRC) so it's very different and probably wouldn't give a good idea of how it would sound with a "regular" PI. Plus the Bright channel bypass caps bleed off a lot of high end in the Normal channel so...apples and oranges probably.  

Matt I checked what I had done (many moo... -- 5/2/2003 11:42 AM