Measured output impedance of Sony ECM-250 microphone

216Ω


This is measured with an Escort impedance meter while an 1.5V battery is of course inside the mic.


This microphone has a single ended class A circuit (like a Pleiades amplifier) with an output transformer whose primary gets DC too, electrons flowing all the time.


Only a JFET, transformer, battery?


No wonder it sounds brilliant.


Connecting to it a Pleiades (R,L) gentle slope high pass makes it a great close up vocal microphone. See previous post.