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Gain Stage for Wurlitzer 6420 6L6 tube amp







Hello inmates,

need some major help and I also might need some fundamental replies as well.. I posted earlier this month about a pair of Wurlitzer 6420 6L6 organ amps I picked up for a reasonable price.. I have one of them rebuilt and converted to audio use. It's actually not too bad and I didn't exactly put the most pricey parts or tubes into it. These are a cathode self biased amp being driven by a single 6SN7 input. I think these are rated for 18 watts, but when I bench tested them I managed to get a respectable 28 watts out of it..

Pretty pleased with the modest results so far, however if there is one issue, it's the amp needs some better gain. This was an issue suspected to be the case when I first posted.. Well now that I have one of them running properly, Mikey Samra suggests I build a "gain stage" and then pipe into the existing 6SN7. He suggested using either another 6SN7- which I like because I have another one of those tubes I can experiment with, or a 6SL7.

I am not exactly sure how to do this, nor am I exactly sure of what I am doing by creating a gain stage, but it looks like I can steal some power off the b+ which is around 450 and head into another tube, which I can mount since I wont be using the old speaker sockets, I can install a tube socket in where these are..

Mikey says to look for a similar set up and copy the schematic, but I have not had any luck finding something similar or knowing if it's in fact a gain stage I am seeing.. I was wondering if anyone out there would either know how to do this, or be able to point me to a schematic I could copy directly or with minor changes..

I am posting the schematic that Fender Lover cleaned up for me and two images of the amp.. I need "novice" bone-headed simple direction..:)

thanks for any help

Jeff






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Topic - Gain Stage for Wurlitzer 6420 6L6 tube amp - mr9iron 15:45:52 02/18/17 (17)

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