Aions Ares project which is based on Echoplex EP-3 Pre Amp which includes an onboard voltage doubler for more headroom. Schematic and info on J FET selection avaiable HERE.
'Note that there is two ground connections on the board, the purpose is to reduce any potential noise from the charge pump. Those wires can be connected to any off board ground points like your audio jacks and DC jack. I also replaced the Drain resistors with trimmers for fine tune the bias.
