05-27-2012, 04:03 PM
I think there is a mistake in that sch. There is o DC bias on the 75's pate if you trust it. Can't be that way. Methinks there should be a tedot between #28 70k resistor lower point and the post-fied coil voltage (B+is it), then it makes sense as it also goes to the seond #50 8uF cap.