Astatic W30 aka JT30

The original Astatic JT-30 was introduced in 1939 and had an extraordinarily long life, staying in production in various forms for 74 years. There were many variations in colour, paint and plating styles, . It remains a popular choice for blues harp (harmonica) players, including Keith Graham who has created a fan page for the JT-30 and similar models. (Thank you Keith!)

A dating guide at the JT30.com website suggests that our W-30 is from the late 1940s, based on the 'B' serial number and style of badge.

According to the Shure website, "In 1999, Hohner, the German manufacturer of harmonicas, melodicas and accordions, bought the moulds (and the last existing piezoelectric salt crystals) from Astatic to continue production of the popular JT-30 Blues Blaster crystal microphone. Favoured by blues harmonica players for its dirty, distorted Chicago blues sound, the rechristened Hohner 1490 Blues Blaster ended its production in 2013. "

From a contemporary Astatic leaflet:

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 grey 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. The crystal used is a genuine 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-grey, a rich, soft, lustrous surface that shows off the attractive modelling of the JT Microphone to excellent advantage, One model is opalescent grey 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 buy a T-shirt with the JT30 on it.