I'm helping a friend with this circuit:
It uses dual 6418s operating in single-ended as a "stereo buffer", not all that sure what it means. Anyway, he wants to use it as a headphone amp, but gets a bad impedance mismatch when hooked up to low-ohms headphones...obviously needs a matching transformer.
How do I figure out the characteristic impedance of the circuit, so I know what impedance ratio transformers to tell him to get?
Ignore the hand-drawn notation, we were adding a battery power option.