A superb omnidirectional crystal microphone used by discriminating Harmonica musicians. The JT 30VC’s high output crystal element has been factory tuned to provide just the right presence or “bite” to create the ideal sound for blues and many other styles of play.

The rugged JT 30VC has a die-cast zinc housing which is “cup shaped” for a comfortable fit in the palm of the hand, and the JT 30VC includes an easy to operate volume control. It is elegantly finished in a non-reflecting black urethane paint with a brass plated grille.


Frequency Response

Generating Element:
Polar Pattern:
Frequency Response:
30 Hz - 8 kHz
Open Circuit Voltage:
-49 dB (0 dB = 1 volt per microbar) @ max. gain
35 mV/Pascal
High (Recommended load is 250K ohms minimum)
Positive Pressure on Diaphragm generates a positive voltage on pin 3 relative to pin 1
Die Cast Zinc Alloy
Body - Black urethane paint
Grille - Chrome Plated
NET Weight:
241 grams (8.5 oz.)
285 grams (10 oz.)


Buy the Book!

I cleaned up my tab for Sonny Boy's Help Me and made it into a short book. There's a Kindle version for 99 cents, and if you buy the paperback you get the Kindle free.

Playing "Help-Me" In the Style of Sonny Boy Williamson II: A step by step, note for note analysis of some of Sonny Boy's Signature Riffs

I also write Science Fiction, so you can sample some of my best stories. Also available in Kindle format.

Error Message Eyes: A Programmer's Guide to the Digital Soul

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The JT30 Page Popular links

I began collecting data about the microphones used by blue harp players before there was an internet. I began organizing it into JT30.com in the late 1990s. I accumulated more stuff than I remember. This is some of it.

Street Theory

A Harp Player’s Guide to Music Theory

Learning Harp

Picking Up Blues Harp

A guide to learning to play Blues Harp

Microphone Information

Usenet Articles

Harp Amps

I've been collecting Harp Amps for a while. This is the old Harpamps.com website. There is lots of information here. Here a coupld of links.

Harp Tab

A collection of songs and riffs that I’ve worked out over the years, plus some libraries of stuff I’ve converted to tablature. I’ve included most of the notes and instructions that helped me when I was learning to play blues harmonica.

Basic Riffs Simple harp tabs for songs Blues riffs and phrases.

Harp-L Archives 1992 to 2002


Harp Frequently Asked Questions