MOTM - Unknown French Broadcast microphone

The Microphone of the Month column has been sadly neglected this year, simply because a record number of mics came in for repair, and it has been a challenge to keep up. But some rare and fascinating microphones have passed through the workshop this summer, amongst them this broadcasting beauty from France.

I don't know the make or model of this one and it has no markings or badges on the outside or within, but it looks fantastic. The body is made of two cast metal grills, with a cast yoke.

The connector is an unusual three pin affair, which the owner informs me is a SOCAPEX model which was common in France in the 1960s.* The yoke would sit on a custom mic stand adapter, secured by the thumb wheel.

The motor is nicely machined and uses four large wide U-shaped magnets to provide the field through custom pole pieces.

One quirk of the design is that the magnets must be removed to fit the new ribbon. This takes an extra couple of minutes, and on the plus side this means that one's tools are not pulled by the magnets. Care must be taken to get the magnet polarity right when putting it all back together.

The transformer sits in a (presumably) mumetal can at the base. This one is a 50 ohm model, like most of the Melodium broadcast mics of the era.

Thanks to Philippe Labroue for the microphone and information. Philippe has a fantastic French language audio site with lots of interesting podcasts and information.

*Socapex are now owned by Amphenol