Shure Model 578S Omnidyne
omnidirectional dynamic microphone

General
The Shure Model 578S is a slender dynamic microphone designed to provide wide-range reproduction of music and voice. This omni-directional microphone is ideal for high-quality public address, theater-stage sound sys­tems, and recording applications. It is also recom­mended for interview use where “hand-a-bility” of the microphone is important.

Microphone Features

• Uniform frequency response from 50 to 15,000 Hz
  
  
• A slender modern design, light weight
  
  
• A built-in On-Off switch—an integral part
  of the connector assembly
  
  
• Selection of either high or low impedance
  
  
• Versatility—for use on a floor or desk stand—
  indoors or outdoors
  
  
• Dependability under all operating conditions
  
  
• Ruggedness—will operate for years without
  deviation from original standards
  
  
• Detachable cable with professional three-pin
  female audio connector attached on the micro-
  phone end of cable

Impedance Selection
The Model 578S is supplied connected for high-
impedance operation. To change to low impedance,
proceed as follows (see Figures B and C):

1. Remove the two 2-56 screws holding the switch
   to the connector and switch housing.
   
   
2. Remove the nameplate and gently withdraw
   the switch from the switch housing.
   
   
3. Unsolder the ORANGE lead from its terminal and
   solder this ORANGE lead to the switch terminal
   that has the WHITE lead connected to it.
   
   
4. Reassemble the switch and nameplate to the
   switch housing. Tighten the screws securely.
   
   

Connections
For high-impedance operation (as supplied), the WHITE cable lead is the “hot” con­duc­tor; the BLACK cable lead and SHIELD are con­nected to the amp or chassis ground.

For balanced-line low-impedance operation (after changing impedance as instructed above), the BLACK and WHITE cable leads are the “hot” con­duc­tors; the SHIELD is connected to the amplifier or chassis ground. The low-impedance connection is recommended where long cable lengths are required or under conditions of severe hum disturbance. The permissible cable length is practically unlimited, since neither response nor level is appreciably affected. Shure Model A95 Series Line Matching Trans­form­ers are available for use in those cases where a low-impedance micro­phone line is desir­able, but the associated amplifier has a high-impedance input. These transformers provide a proper im­ped­ance match between a 25 to 200-ohm microphone line and a high-impedance input, and are available with various input and output connectors.

Text and illustrations from Shure Data Sheet 27A279 (OF) ©1974
The Shure Model 578S was manufactured from 1964 through 1977.

Download the Model 578S Data Sheet.