Epiphone Valve Junior Head

[bagger78]

welcome to the world of tube addicts. another alternative to an 12ay7 is a 5751, which is at 70% instead of 60%. ive got a eh and an nos jan ge coming to clean up my crate vc 20 and to try in a silverface fender music master bass amp to pick up a touch more gain. swap em around with the full retube on the crate to see what does which to who. eurotubes doesnt have them so daves tubes, or tube store will have em . eurotubes the only way to go for jj's tho. great helpful people there. be prepared tho to get a soldering iron and a box for extra tubes ,caps ,and fiddely lil parts because now youre entering (cue music....DUN...DUN...DUN) "THE TWEAKHEAD ZONE". dont forget to shop for a tablesaw to make all the boxes for the speakers youre gonna collect on e-bay. dont ask me how i know all this. enjoy

[tunghaichuan***]

Here is a reply I posted on the Gibson/Epiphone board:

One thing to consider: even though the 12A*7 type tubes look alike superficially and share the same pinout, a 12AU7 is *not* a low gain 12AX7. A 12AT7 is *not* a lower gain 12AX7, nor is a 12AT7 a higher gain 12AU7. Some tubes like the 12AY7 happen to be close enough to use in 12AX7 circuits (like Fender did in their 50s tweed amps). But all these tubes differ in their characteristics. Dropping a different tube into a circuit designed for a 12AX7, may work for you, but it will not be optimal unless you change the cathode and anode resistors. But since we are discussing guitar amps, you may or may not like the results.

tung