Hi, I wish 2 build a JTM50 copy & have bluesbreaker reissue PT. Along with GZ34 rectifier amp uses 4x 12AX7's so I would like to add a switchable cascading gain section with the extra dual triode. I have the Jose A mod schematic but this isnt exactly wot I'm after. I was wondering if there r any other mods of this type around. Cheers