Thank you pete, i'm a your fan!!!!
I understand your argument, I intend to make your pickup for the driver, i think that this is structurally the better.
My problem is the circuit,if I follow the feltzer/ruby's schemathics, i have the datasheet but i don't understand where i put the preamp. Maybe there are two circuits, one for the amp(feltzer/ruby) and another one for the preamp, but I don't found the datasheet.
Instead i follow the Strib's circuit i have the datasheet but i don't know if this is good for my driver.
I hope that you can help me and can you give me the info and datasheet for a "standard sustainer guide".
Thanx.