Tannoy MR425

The MR425 is mentioned briefly in Wireless world magazine, May 1952:

"The Tannoy range of high-grade microphones has been extended by the addition of a miniature ribbon microphone (MR425) and a pressure type (MC424) with sockets designed to fit American stands."

From the Xaudia blog:

The Type 1 mic was succeeded by the MR425 or "Pitchfork" model, which is much smaller and has a completely new motor design. This model seems to date from the early 1950s and was available in different colours with different mounting options. Most of these models have a 600 ohm output, and give a full well balanced sound.

This is my favourite figure-8 Tannoy, partly because this was the first Tannoy mic that I owned, but also because it has a good response and a very usable signal / noise output.

600 ohm output impedance.

The MR425 shares a motor design with the uni-directional model MD422.

The motor is simple but nicely made, with two tapered magnets either side of the ribbon, and adjustable clamps allow the ribbon tension to be adjusted.

A round-up of Tannoy ribbon mics at the Xaudia blog.