following the wires, between terminals 2 and 4, I get 0v with the balance pot turned all the way to the left, and 1.1v with the balance pot turned all the way to the right. between terminals 12 and 14, I get 1.1v with the balance pot to the left, and 0v with the bal pot turned to the right. I guess the next steps involve turning the preamp on, so I'll wait for further instructions