Shure 717B User Guide

DATA SHEET

DATE: August, 1944

No.

136

SUBJECT:

Model 717B Crystal Hand Microphone

MODEL 717B CRYSTAL

GENERAL:

high quality reproduction of sound. The crystal used is a grafoil (high capacity) bimorph unit, moisture-sealed to withstand adverse climatic conditions. The microphone is provided with a 7-foot shielded rubber- jacketed cable.

APPLICATIONS:

response is suitable for either voice or music, and

is free from undesirable peaks. The cartridge unit is mounted in rubber to provide mechanical isolation

from the case, so that the microphone may be handled or carried about without annoying mechanical noise pickup.

CONNECTIONS:

a load resistance of 5 megohms. Input resistances as low as 1 megohm may be used if necessary but higher values are recommended becauseof the better low-frequency response obtained. The shield should be connected to the chassis.

INSTALLATION: The 717B Microphone is designed to

amplifier cabinet through the use or a No. 47-54 clip or it may be fastened in a No. 99-120 stand for table use.

OPERATION: No polarizing voltage is required for

if accidently connected to loud speaker or power

supply outlets carrying high voltage. Check your

connections carefully.

in places where the temperature exceeds 125°F. They

should not be exposedto the rays of the sun in very hot weather for any considerable length of time - or left in closed automobiles parked in the sun during hot weather, as the temperature inside the automobile may easily build up to over 125° end permanently damage the crystal.

minimum length of cable consistent with placement requirements. Careful grounding of the cable shield

is advisable.

Voltage Sensitivity:

at 400 cycles. This is equivalent to 53 db below

1 volt per bar at the terminals Of the 7-foot cable.

Internal Output

Recommended Load

Model 717B is a pressure-actuated diaphragm-type semi-directional crystal

microphone with wide range response for

The Model 717B is designed for announcing, home recording and all general purpose use. The frequency

The inner conductor of the cable should be connected to the grid of the first tube in the amplifier across

be held in the hand. However, the Microphone may be mounted in the

crystal microphones.

Crystal microphones may be seriously damaged

Crystal microphones should not be used or kept

When used near a radio transmitter, use the

SPECIFICATIONS

2.2 millivolts r.m.s. bar at the and of a 7-foot cable across, 1 to

Impedance :

Equivalent to a 1,500 micromicrofarad condenser.

1 to 5 megohms.

5 megohms

HAND MICROPHONE

Model

Height, Overall. . . . . . . . . . . . .

Height, Case Width Thickness Finish Net Weight

Shipping Weight. . . . . . . . . . . . .

Code Word (7’ Cable) . . . . . . . . . .

GUARANTEE:

date of shipment from the factory, provided all

instructions are complied with fully. In case or damage, return the microphone to the factory for repairs. Our guarantee is voided it the microphone case is opened.

LICENSE NOTICE:

. . . . . . . . . . . . . . . . .

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SPECIFICATIONS-Continued

717B

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Each microphone is guaranteed to be free from electrical and mechanical

defects for a period of one year from

Shure patents pending. Licensed under patents of the Brush Development Company.

2-l/2" 2-1/2" 1-1/2”

Brown 3/8 Lb. 3/4 Lb.

RUDUK

Printed in U.S.A.