MS Mic V2

The main part of the circuit is constructed on a Radio Shack Multipurpose PC Board (Cat # 276-150).

The mic capsules must be modified for use in this circuit. For more complete details see Mic Modification and Mounting.

Here's the whole shebang before mounting in the case.

With the mic head mounted directly on the case, the mic is very sensitive to handling noise and floor-transmitted noise. I used a length of five-conductor-plus-shield-and-drain cable and DIN connectors to make an extension cord so I could use the mic with a conventional mic stand. The capsules are a bit sensitive to hum pickup, so I made an enclosure out of brass mesh. The mesh assembly should not be soldered directly to the DIN connector because this results in a VERY resonant structure, almost like a tuning fork. I wrapped the top of the DIN connector with weather stripping and fitted the mesh enclosure over that. The mesh is grounded to the DIN connector with a piece of wire and a wrapping of electrical tape completes the assembly.

The batteries, power switch, output jack, and 100uf filter caps (mounted on the small piece of perf board) are housed in the bottom of the enclosure. A rubber grommet on the hole between the halves of the enclosure prevents shorting of the wires by the sharp edges of the hole. Pieces of a plastic binder separator sheet are glued to the lids of the Altoid boxes to prevent shorts.

This circuit modification allows you to switch between a stereo or mid-side output. When the circuit is switched to MS mode, the Width control adjusts the level of the side output relative to the mid output.