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EL34 Conversion for Ampeg V-4

12/23/2003 3:59 PM
Paul Drexhage
EL34 Conversion for Ampeg V-4
My friend recently purchased a rather beat old (early 70s) V-4 that had been modified (sort of) to accept EL34's. The reason I say "sort of" is because, while the screen resistors and some other resistors in the power section were changed to accommodate for the EL34s characteristics, the previous tech neglected? to jumper pins 1 and 8 of the power tube sockets together. Correct me if I'm wrong, but from what I understood about this conversion, it was a good idea to tie pin 1 and 8 (screen and cathode) together to mimic the configuration of a 7027A. I've already tried it both ways (w/ pins jumpered and w/o) without a noticeable difference at low volumes (haven't cranked it yet). Any help is greatly appreciated. Also, any suggestions for bias on the EL34s when run in this configuration?