Boston Section

The Boston Section of the Audio Engineering Society met on September 12, 2002 for a presentation by David Smith, of Sony Music, on vintage condenser microphones.

David made a distinction between himself and others who work on vintage microphones by emphasising that his goal is not to improve upon a microphone's design, but to restore the microphone to its original state and sound quality. To illustrate his work, David presented schematics of original microphone and power supply designs, starting with the venerable Neumann U47. He noted that certain capacitors and resistors would degrade over time and replacement, a relatively simple task, would allow the circuit to function as designed.

Additionally, David showed how the designs of condensers became more intricate through presentation of the schematics of the tube Neumann M49, U67, the AKG C12, and Telefunken ELAM 251, and then the transistor Neumann U87, AKG 414, and the Schoeps CMC5.

David stressed the importance of cleaning the capsules on vintage microphones. This restores much of the original sound of the microphone, so much so that it may sound quite different than those left uncleaned. He pointed out that cleaning the capsule is a delicate process, and is best left to a professional.

The presentation ended with a brief Q & A. The Boston AES would like to thank David for his presentation.

Matt Girard