In this episode Canelina the cat and her friend the patient tortoise...
Have found out that a very cheap, overlooked by almost anyone microphone, going on ebay for peanuts has the same capsule as one of the best microphones on the planet (Sennheiser MD211).
The cheap found mic is the lavalier MD214 (MD 214 N) from the same manufacturer.
They are very reluctant to mod it but eventually they give in with the consent of the mic itself. But they promise to the mic to do everything is such a way that undo is possible.
After bypassing the electrical EQ filter of the mic, they obtain direct access to the legendary moving coil capsule.
Then in order to make a world class preamp for it, they get an input transformer. an EF183 electron tube and an output transformer.
They connect the anode, screen grid and suppressor grid of the electron tube together.
They connect the input transformer to the grid circuit.
The output transformer to the anode circuit.
They connect a grid accelerating electron resistor from anode to grid. They got the idea from the wise girl and they call this front end amplifier the Pleiades V6 preamplifier.
Just a 3 to 4 volt battery for the anode circuit and deliberately underheated heaters make the front end sing.
So they achieve a world class state of the art microphone that shines like a diamond.
Low noise too!
Other variation of the story is that they save a bit more to buy the MD211 itself or some other fabulous mic. Or that they buy some ring (toroidal) cores to wind their own signal transformers etc.
References:
Sennheiser Micro Revue 70-71
http://lcweb2.loc.gov/master/mbrs/recording_preservation/manuals/Sennheiser%20Micro-Revue%2070-71.pdf
On preserving transconductance of electron tubes at anode potential as low as 3 volts - euroelectron
http://euroelectron.blogspot.gr/2017/03/on-preserving-transconductance-of.html
Operating features of the Audion - Edwin Armstrong
They go about recording a great vocal.
(Perhaps on more than 1 episode).
Public Domain.
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