In order to confirm that the Unidyne III cable with Amphenol, Neutrik connectors had been made wrong or phase reversing the following experiment was done.
If on a mono (one channel) setup we speak in front of 2 microphones that are connected out of phase, silence should result.
So in order to connect the mics in phase pin 2 from Unidyne III was connected to preamp mic in pin 2.
A crocodile jumper cable was connected from Unidyne III pin 3 to pin 2 of Unidyne B 515SD. And pin 3 of Uni B to pin 3 of the mic preamp.
The 2 mics almost canceled each other so the Unidyne III is confirmed to be connected out of phase.
When both mics were connected in phase the sound through headphones was very clear from each mic.
The ambience sound was very loud too. Surprisingly loud. And lower noise. This can be explained by the fact that we have 2 mics which make a total impedance of 400Ω. Ambience sound was the one transistor class A setup in a far away room, Peiades 2N3053 to Philips AD5046N.
Voice was very clear too and loud. No wander why the president of the United States speaks in front of 2 Unidyne III or SM57.
It was very easy to compare between 2 mics and 1 by switching off the 515SD. The short circuit made only the Unidyne III signal available to the preamp.
Connecting 2 mics in series is the mathematical equivalent of adding their voltages at any instant in time. In parallel it should be adding the currents?
Signal path, setup:
Shure Unidyne III + Shure Unidyne B - Sony TC-D5 pro - Sennheiser HD580
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