microphone Microtech Gefell UM 92.1 S

Posted on Feb 5, 2014

The M7 capsule is a center-terminated, dual-diaphragm design, and supports three polar patterns. A switch on the power supply allows selection of Cardioid, Figure-of-8, or Omnidirectional patterns. The amplifier circuit is similar to some of Gefell`s historical models, the CMV 563 and UM 57, but has been updated with modern components. The tube is

microphone Microtech Gefell UM 92.1 S
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an EF 86 pentode, reportedly of Russian origin, wired in triode configuration. The. 1  Gefell mics, including the M92. 1S and UM92. 1S, include RF/EM protection circuits required for CE compliance. Although US restrictions on electromagnetic radiation are less strict, Gefell does not currently provide US-only circuits. According to Oliver Archut of TAB-Funkenwerk, these EMI protection circuits choke  the sound and introduce phase shift. He has provided instructions for removing the EM/RF circuitry of the UM92. 1S. See also this clarification. Using Oliver`s suggested modifications, I changed my stock UM92. 1S by: clipping the 1. 5k resistor and sending the cathode wire to ground; installing a Telefunken EF86 tube with hilumin shield; installing the same x-former that is used in the UM75. The mic ships in a metal suitcase and includes a dedicated power supply (p/n UN 920. 1), power cable (p/n C 92. 1), elastic suspension mount (p/n EA 92), and gray foam windscreen (p/n W 92). Note that the frequency-response graphs on the MTG website for the UM 92. 1 S (and M 92. 1 S) are identical to those of the UM75, UMT70S, and MT71S, despite the wild variation in topologies, circuitry, and headbasket design among those microphones. The graphs linked below are samples from an individual UM 92. 1 S, and are therefore much more predictive of this micG ½s performance. the UM92. 1S has a fat, round tone, with a lot of midrange complexity...

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