General Description

Contoured to fit comfortably in the palm of your hand, the Model 520DX "Green Bullet" microphone produces the unique sound that has made it a legend among harmonica players.

The 520DX features a volume control knob at the base of the microphone that allows musicians to make adjustments to suit their needs during a live performance. An attached cable with a standard 1/4-inch phone plug allows the microphone to be connected to a high-impedance device.


Connect the 520DX directly into a guitar amplifier to produce the classic blues harp sound. Use the following guidelines:

  • The volume control on the microphone should be turned down before plugging it into an amplifier. As you move away from the amplifier, the volume can be turned up.
  • Adjust the microphone's volume control knob during performances as needed. For example, when switching from playing rhythm to lead or to place the microphone on standby between sets.
  • To avoid feedback, maintain as much distance as possible from monitors or loudspeakers. Adjust the volume of monitors or loudspeakers at the mixing console so that no feedback is present when the volume control knob on the harmonica microphone is at its maximum setting.

The volume setting of the guitar amplifier may have a significant effect on the overall tone produced. Experiment with different microphone and amplifier volume settings to achieve the desired effect.

Volume Control

Low Impedance

To connect the 520DX to a low impedance device, such as a mixer, use a low-to-high impedance-matching line transformer, such as the Shure model A95U.

The 520DX can be rewired for low impedance, but this disables the volume control. Contact the Shure Applications Group at (847) 600-8440 for more information.



Dynamic (moving coil)

Frequency Response

100 to 5,000  Hz

Polar Pattern



High, unbalanced

Load Impedance Range


100 kΩ

Output Clipping Level

at 1kHz, open circuit voltage

-38.0 dBV/Pa (13 mV) [1]


Positive pressure on diaphragm produces positive voltage on tip with respect to sleeve (ground) of microphone output phone plug connector


6.1 m (20 ft) two conductor shielded with standard 1/4-inch phone plug attached (supplied wired for high-impedance, unbalanced connection)


Green and chrome finished die casting


63 mm (2.5 in.) max diameter, 82.6 mm (3 1/4 in.) long

Net Weight

with cable

737 g (26 oz.)

[1] 1 Pa = 94 dB SPL

Typical Frequency Response


The RED lead is the high-impedance audio output; the SHIELD is the audio return and case ground.

The Model 520DX Green Bullet Microphone is supplied wired for high-impedance, unbalanced operation with the 1/4-inch phone plug.

Internal Connections


Replacement Parts

Cartridge for 520DX


Cable and Plug


Volume Control Pot



This product meets the Essential Requirements of all relevant European directives and is eligible for CE marking.

The CE Declaration of Conformity can be obtained from:

Authorized European representative:

Shure Europe GmbH

Headquarters Europe, Middle East & Africa

Department: EMEA Approval

Jakob-Dieffenbacher-Str. 12

75031 Eppingen, Germany

Phone: +49-7262-92 49 0

Fax: +49-7262-92 49 11 4