Shure 444 User Guide

i

222 HARTREY AVE.. EVANSTON.

IL.

60204 U.S.A.

DATA

MODEL

COMMUNICATIONS

AREA CODE 3121866-2200 . CABLE: SHUREMICRO

@

TWX: 910-231-0048 TELEX: 72-4381

SHEET

MICROPHONE

CONTROLLED MAGNETICm COMMUNICATIONS MICROPHONE

GENERAL

The Model 444 is a pressure-operated CONTROLLED
MAGNETIC@ microphone. It is specifically designed for
radio communication applications and provides opti­mum performance from single sideband transmitters
as well as AM and FM units. The response cuts off

Hz,

sharply below 300 and above 3,000
characteristic to 3,000
acteristic results in optimum speech intelligibility and
audio punch to cut through noise and interference.

Microphone Features:

A response tailored for single sideband transmis­sions

w

A switch for instantaneous selection of Press-to­Talk or VOX (voice-operated relay control) oper­ation

.

Finger-tip control bar (locking or non-locking ac-

tion) to actuate microphone and an external relay
or control circuit

.

~ong-life switch to satisfy severe requirement of
communication systems

Adjustable microphone height chassis ground. (See Figure 1 for internal wiring

w

A sturdy, high impact ARMO-DUR@ base and mi­crophone case

Dependability-under all operating conditions

PRESS-TO-TALK SWITCH OPERATION

The finger-tip control bar can be used as a locking
or nonlocking switch. To use as a nonlocking switch,
simply depress the control bar and release after trans-

mission. To use as a locking switch, depress the
control bar and pull it forward. To unlock the switch,
move the bar back and release.

NORMAL-VOX OPERATION

Most amateur equipment is wired to use either VOX
(voice-operated relay control) or a Press-to-Talk switch.
Model 444 has been designed to provide maximum

flexibility for both types of operation. VOX or
to-Talk operation may be easily selected by the

Normal-Vox slide switch on the bottom side of the
microphone base near the cable entry.

For Press-to-Talk operation of the microphone, the
Normal-Vox switch should be in the "Normal" position.
For VOX operation, the Normal-Vox switch should be
in the "VOX" position, and the Press-to-Talk switch
must be locked in the On position.

Hz.

This special response char-

with a rising

Press-

CONNECTIONS

Model 444 is designed for use with transmitters or

amplifiers having high-impedance inputs. The
cable lead is the

circuit: the WHITE cable lead controls an external relav
circuit. The shield is common to both the microphone
circuit and the external relay circuit. The shield should
be securely grounded to the amplifier or transmitter

diagram of Model 444.)

"hot" conductor for the microphone

r\

BLACK

SHIELD

PRESS-TO-

SWITCH

t

Shure Microphone Cables are selected after ex­haustive tests to insure superior performance in micro­phones because of low capacitance, superior shielding
properties and unusually long life under severe use.

Cables with plastic insulation should not be sub­jected to excessive soldering-iron heat. Carefully clean

and tin the conductors and the connections to which
the conductors are to be soldered. The soldering
operation can then be done with a minimum of heat,
thereby avoiding any possibility of damage to the

cable.

6G-3

7

TALK

GROUNDED TERMINAL

OF CARTRIDGE

-

INTERNAL

IMPORTANT

-

-

YELLOW

CONNECTIONS

FIGURE

iO1

?-

1

j

m-----

i

\

I

I

\{

----

I,,)

SWITCH SHOWN IN

'NORMAL" POSITION

NORMAL

!\

;

!:

!

BLACK
WHITE

444

SHIELD

BLACK

-VOX

Copyright

27A245

(RJ)

1978,

Shure

Brothers

Inc.

(OVER)

U.S.

Patent

Printed

D-198,850

in

U.S.A.

SPECIFICATIONS

TY pe

CONTROLLED MAGNETIC@

Frequency Response

200 to 6,000 Hz (See Figure 2)

+

20

-

-

+I0

Z

Y

L

z

0

D

r

5

-10

Y

-20

1

I

I

PO

w

I I l llllll

100 lP00 lO.000 2opoo

TYPICAL

FREWENCY

FREQUENCY

FIGURE

Polar Pattern

Omnidirectional

lmpedance (at 1,000 Hz)

Microphone impedance is "High" for connection to
high-impedance microphone inputs

IN

HERTZ

RESPONSE

2

I

I IIIIIII

Dimensions

See Figure 3

6.4mmllI4 INITRAVEL

TO

OPERATE SWITCH

1

I

OVERALL

DIMENSIONS

FIGURE

3

..........

Net Weight

680 grams

(1% Ib)

Packaged Weight

964 grams

(2% Ib)

Load lmpedance Range

Minimum, 15 kilohms
Recommended, 100 kilohms

Output Level (at 1,000 Hz)

Open Circuit Voltage

........

Loaded with 100,000 ohms

*O

dB = 1 volt per microbar

-

53.0 dB*

...

-54.0 dB*

(2.25

Switch

Press-to-Talk switch-locking or nonlocking oper­ation to actuate microphone and an external
or control circuit

Normal-Vox switch-single-pole double-throw slide
switch in microphone base to provide either

voice­operated relay control or Press-to-Talk microphone
operation

Cable

2.lm

(7

Non-detachable

ft), two-conductor shielded

plastic jacketed

Case

Two tone gray

ARMO-DUR@

mV)

relay

REPLACEMENT PARTS
Cartridge
Cable

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

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

Screen and Grille Assembly
Press-to-Talk Switch

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

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

R5R

70A293

.90A1060

.90A946

GUARANTEE

This Shure product is guaranteed in normal use to
be free from electrical and mechanical defects for a
period of one year from date of purchase. Please
retain proof of purchase date. This guarantee includes

all parts and labor. This guarantee is in lieu of any

and all other guarantees or warranties, express or

implied, and there shall be no recovery for any con­sequential or incidental damages.

SHIPPING INSTRUCTIONS

Carefully repack the unit and return it prepaid to:

Shure Brothers Incorporated

Attention: Service Department

1501 West Shure Drive

Arlington Heights, Illinois 60004

If outside the United States, return the unit to your
dealer or Authorized Shure Service Center for repair.
The unit will be returned to you prepaid.