Shure 3B, 10B User Guide

TELEPHONE DELAWARE

8383

CABLE SHUREWICRO

DATA

DATE:

SUBJECT:

1

SHEET

August 1937

Models

Carbon Microphones

3B

and

No.

10B

1o1B

GENERAL

MODELS

:

Model

3B

Carbon Microphone

inexpensive two-but

3B

and 10B

t

on microphone

is

an

for general-purpose use in medium

is

fidelity systems where low cost
tant factor. Model

3B

is

designed for spring-

the impor-

suspension in microphone rings.

Model
equivtlent to Model 3B in performance.
able

10B Convertible Hand Microphone

is

Remov-

Quickway" Hooks are furnished for con­verting from hand type to conventional type
for spring suspension in microphone rings.

Model

10B

is

fully assembled and wired, and

is

furnished with 3-conductor cordage 6 feet long.

APPLICATIONS: Typical applications of Models

3B

and 10B are found in low cost

portable and mobile public ad­dress equipment, announcing and paging systems,
amateur radiophone transmitters, etc. The con­vertible feature of Model

10B

makes

it

especi­ally convenient where limited equipment must
be used under a wide variety of service condi­tions.

3B

is

INSTALLATION: Model

designed for spring
suspension mounting in carbon
microphone rings in the usual

manner. Model

be

can

a

quickly converted for stand mounting in

carbon rina. Loosen the three binder head

10B

is

a hand microphone which

terminal screws and disconnect the cable. Re­move the three

screw? that hold the microphone
head in the close-fitting ring and slip the
head out of the ring. Screw "Quickway" hooks

into the tapped holes in the frame. Mount in

carbon ring with springs

(Shure A30A or

A31A)

in the usual manner. Simply reverse the pro-

cedure to convert back to hand-type microphone.
CONNECTIONS: Suggested wiring diagrams are

Fir.

A.

shown in

may

rent

be controlled by either

The button cur-

the rheostat or potentiometer method as indica­ted. The potentiometer method
some engineers because

it

is

preferred by

allows the current

to be gradually reduced to zero before the

is

microphone

disconnected, thus reducing the

possibility of "packing".

To use Models

microphones, terminals

an& 10B

A

and

n

:s

le-button

butto;

3B

and frame as indicated in the "end-view
sketch) are connected to the microphone trans­former primary, in series with the button cur­rent source. The recommended and maximum but­ton currents

(see OPERlTION below) are the same

as for two-button operation.

Suitable microphone

transformers are a-

vailable from most radio parts distributors.

CARBON

MICROPHONES

Model 3B

Carbon

Nicrophone

(~bove)

Model 10B

Convertible Hand

Microphone

(At

right)

OPERATION: The f ollowing button - current

7

ma. per button. Maximum Current: 12

h..++nn

UULILIVII.

Under no circumstances should the
current rating be exceeded.
results in better quality of
er hiss level, and long life. lCxcessive cur-

will

rent
phragm. Do not leave
phone for extended periods when not in use.

"Packing".

currents exceeding 7 ma. indicates packing

The possibility of "packing" can be reduced to

minimum by: (a) careful handling to reduce

a
shocks and jars;

current

to1a minimum before disconnect ing the
microphone or batteries;
button current before moving the microphone.

Should "packing" occur, the microphone
can usually be restored to normal condition by
tapping lightly on the frame with a rubber­tipped

penail while rotating the instrument.

If this procedure fails, the diaphragm or car-

bon has probably been burned and the microphone

should be returned to the factory for recondi-

ti

ocing.

Dampness.
ing of the carbon granules, and
fore important to keep the microphone

place.

ratings apply to Models

10B: Recommended Current

ma.

WImUm

Low

button current

reproduction,low-

cause burning of the carbon and dia-

button current on micro-

A

dif ference between thentwo buttnon

(b) gradually reducing button

(c) turning off the

Excessive dampness may cause coher-

it

is

3B

and

:

4

to

per

.

there-

inadry

@

SHURE

BROTHERS

1997

PRINTED

IN

U.S.A.

No.

101~

DATA SHEET

225

WtSl

HURON

STRffl

CHICAGO

U0S.L

0-25

0

(FRAME)

4f

SPECIFICATIONS

Voltage Sensitlvlty: 4 millivolts

bar across 200 ohms at 400
cycles.

Output Power

Recommended

Impedance

Le~el: Minus 29 db in 200 ohms at

400cycles. (0db=6m.
Sound Pressure, 10 bars.)

Load

:

200-ohm input transformer.

Button Current:

WLT

R.

DRY

M.

CELL

S. per

,CLOSED

1000 OHM RHEOSTAT.

METER

MErm

-C/RCU/T

JACK

JACK

Fig.

#/CROPHONE

TRANSFORMER

A.

3B

AND

10B

P

30 40

Guarantee: Each microphone

date of

free from electrical and mechanical de­fects for a period of one year from

shipment from the factory, provided all in-

structions are complied with fully.

SHURE MODEL

AZIMUTH 0 DEGREES

TERMINATION: 200 OHMS

60

80 100 I

FRENQUENCY, CYCLES PER SECOND

3B

MICROPHONE

M

is

guaranteed to be

2

M

4M 6M8MlOM