Connecting the SONY ECM-250 electret condenser microphone directly the iPad or iPhone

At your risk.


Is it possible?


By removing the battery from the mic and connecting to + the pin from iPad headphone-mic connector that gives +volts and to negative (spring terminal) the pin giving ground.


It should work the circuit is closed (electrons flow) though the mic FET, the mic output transformer, and iPad's load resitor.


In fact the normal mic output should be available (secondary of its output transformer). If needed a Pleiades R,L filter can be connected to reduce bass heaviness for close mic mouth vocals.


Of course other electret condenser capsules could be directly connected.


Or moving coil mics using a Pleiades K117 single JFET amplifier.


Or an electron tube with Pleiades bias can be connected so that anode current is possible with just the few volts that iPad will give. Heater voltage can then be supplied separately by 1 larger battery. (Always use a fuse in series with any battery for short circuit safety). At the grid of the electron tube through a coupling capacitor an electric guitar, moving coil, printed ribbon or ribbon microphone can be connected. Normally a microphone input transformer should be connected between moving coil and grid circuit to step up impedance or voltage further lowering noise.