Thanks for the help. I'm glad I don't need anything else to run this tach.
Where did I get the idea an amplifier is required? Is that an older style tach that requires an amplifier?
The original 'electric' tachs from the late fifties and early sixties all required a transmitter box. In addition to their own power source (mercury cells)
SunTach Transmitter Boxes contained some large transistors and a relay.
It wasn't until later on that this could all be miniaturized to fit inside the tach head . . .