Connecting the Sennheiser MD 211 N to Western Electric D163851 input transformer

The sound seems to be transformed like a magical miracle.


Signal path, setup:


Male singing voice at 1-4in - Sennheiser MD211 N - Western Electric D163851 - Sony TC-D5 Pro at XLR mic in - Sennheiser HD580


The world class MD 211 N is shinning at its revealing glory.


The Western Electric transformer acts as a magnifing focusing glass for voice.


The singing voice sounds coming big back at you. Like the mic becoming a Hoover sucking the voice.


First time such a low turn ratio experiment was done at Pleiades lab-studio with a Western Electric signal transformer. It is understandable that Western Electric transformers score so high on eBay.


The WE D163851 input transformer had come from a 1930? 1940? 32A (SPL) Transmission Measuring Set X-66065A. It has an orange military stamp and it was found at a military surplus yard on around 2000.


It is the front end of the transmission measuring set, should be of great bandwidth. The turns ratio is 1:2. This means the output impedance connected to it with be quadrupled.


Primary inductance is aproximately 1H. There is another primary of 1H which was not connected. The secondary inducstnce was measured to be around 4H.


The not low but not too high 1H input inductance seems to be doing a fine job of cutting the bass heaviness (Fletcher-Munson, voice effort curves) by extinguishing it right at the output of the microphone. The mic output inpedance and L form a RL low cut filter.


The Sony is driven in a big way. Before being accustomed to using this transformer the VU meters were heard to click at the max end of their moving path scale.


Before connecting the mic there was some hum which was reduced by rotating the handful big and heavy transformer 90 degrees. Some hum and noise was still heard which disapeared phenomenally the moment the mic was connected.


Now that mics can be compared at same impedance...


Compared to the present Pleiades reference mic AKG MI 201-100 the MD211 N sounds at least as loud and with more high frequency detail which is not exaggerated.


How would a world class mic and this or another 1:2 of comparable quality transformer sound with the Uher 4200 report reel to reel portable analog recorder?