CineMag worked with Wes Dooley from the very beginning of AEA.  The first project was to develop a version of the venerable and cherished RCA 44 velocity “ribbon” microphone.   One of the challenges was that the materials for the original were no longer available in the same grade.  We also needed to enhance transformer immunity from stray magnetic field interference such as from power transformers.  Even thought the impedance of the ribbon “motor” is very low, the transformer deals with micro-volt levels and must reject any pickup.  We settled on a hum-bucking transformer topology.  The original ones were susceptible.

Another problem is making the transformer behave the same way as the original did acoustically.  Matching that required quite a few iterations of the transformer design.