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.
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):
Remove the two 2-56 screws holding the switch to the connector and switch housing.
Remove the nameplate and gently withdraw the switch from the switch housing.
Unsolder the ORANGE lead from its terminal and solder this ORANGE lead to the switch terminal that has the WHITE lead connected to it.
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.