Astatic W30 aka JT30

The JT30 is much loved by harmonica players, who appreciate both the sound of the ceramic element and the convenient shape that fits neatly into ones hand.

From a contemporary Astatic leafet:

Because it fills, so completely, a long standing demand for a really good microphone for general usage at a popular price, Astatic's JT-Series is being received with wide acclaim. Its range of usefulness has been demonstrated to cover amateur, home recording and public address requirements with equal effectiveness and satisfaction. JT-Series Microphones are manufactured in practical wide-range models, semi-directional in design, and are made available in choice of two tone opalescent gray and chrome or all-chrome finishes.

PERFORMANCE- A matched acoustic design results in a pleasing bass response uniform highs, free from objectionable peaks or dips. The entirely new mechanical design features a heavy die-cast cartridge housing, with corrosion-proof diaphragm completely protected against abuse. The massive cartridge freely suspended within the outer case produces a microphone dead to "vibrophonics" (extraneous noises from case, stand and floor). The output level of -52 db provides ample reserve for use in connection with all high gain

UTILITY-A new rigid die-cast case with a fixed-angle position for optimum usefulness offers ruggedness to withstand the hard service requirement of a microphone designed for universal use. Bimorph element completely moisture-sealed with Astatic's new "Ebonite" coating. Complete barometric compensation is also provided. The case is threaded 5/8"-27, fitting standard floor and desk stands. Cable exit, according to model specified, may be through either a spring cable protector or a concentric type cable connector.

BEAUTY-The J-Series Microphones are available in a choice of two beautiful finishes. The basic motif is opalescent-gray, a rich, soft, lustrous surface that shows off the attractive modelling of the JT Microphone to excellent advantage, One model is opalescent gray with bright chrome front, and second bright chrome overall. Quality materials and workmanship, together with the elimination of non-essential accessory equipment, have made the new, popular priced JT-Series, great favourites."

• Output impedance: 5 mega-ohm load.
• Output level: -52 db [below one volt bar).
• Frequency response: Free from objectionable peaks or dips 30-6000 Hz. with downward slope beyond 6000 cycles,
• Dimensions. diameter 2-5/16" height 3 depth 3-1/16%
• Weight: Net weight 12 ounce; Shipping weight. 1 1b. 8 oz.
• Standard equipment .. 5/8-27 stand thread in case

A detailed article about modifying the JT30 for use as a harp / harmonica microphone.

You can even buy a T-shirt with the JT30 on it!