If a microphone needs a Pleiades(R,L) filter...

For example an (80Ω,8mH) Pleiades filter may be needed for a directional microphone of 200Ω so that vocal sound is not bass or mid heavy.


Then said mic is stepped up by an ordinary high inductance input transformer...


Then signal is capacitor coupled to grid of an electron tube operating at 3.7V for both heaters and anode. (See Pleiades V6). Low noise or very low noise so far...


The output impedance of said electron tube configuration with Pleiades bias may be 20KΩ.


So the corresponding Pleiadss filter needed for flat frequency response from producer's brain to listener's brain would be:
(8000Ω,800mH)


Such high winding resistance can be when the output transfomer is air wound at ring shape.


Which is good since there won't be saturation due to DC from the single ended electron tube operating in class A, ie electrons flowing all the time.


Output transformer may be 10:1 thereby impedance dropping back to 200Ω. But now signal is stronger than the thermal noise produced by a 200Ω resistor since the electron tube increased the signal. If all components including the electron tube configuration are low noise enough the noise figure of the microphone should be preserved.


But at the same time it will sound correct for vocals from producer's brain to listener's brain.