Shure FP12 Schematic

222 HARTREY AVE., EVANSTON, IL 60202-3696 U.S.A.
AREA CODE

312/866-2200·

CABLE: SHUREMICRO

THE SOUND OF THE PROFESSIONALS®

PROFESSIONAL PRODUCTS

GENERAL l

The FP12 is an in-line, battery-powered amplifier
designed to accept a microphone- or line-level signal,
bridge it, and produce a signal sufficient to drive head­phones at very loud levels. The FP12 is ideal for anyone
in the broadcasting, sound reinforcement or audio re­cording fields who has a need for headphone moni­toring or checking microphone- or line-level cable runs.
In addition, the FP12 can be used to provide multiple
headphone feeds, a two-station intercom, extra power
for existing headphone circuits, or a means of
ing

electronic instruments through headphones.

FEATURES

0

Wide-range frequency response

0

Low input noise and harmonic distortion

0

High-impedance bridging input does not load signal

source

0

Switchable microphone- and line-level inputs

0

Switchable low- and high-impedance headphone out­puts

0

Parallel 3-circuit phone and miniature (3.5 mm) head-

phone jacks
Balanced loop-through locking XLR connectors and

phone jacks

0

Powered by easily obtainable 9V alkaline battery

0

Low current drain for extended battery life

0

Rugged construction, with durable belt clip for field
use

0

Low susceptibility to radio-frequency interference

SPECIFICATIONS

Frequency Response

40 Hz to 15

kHz,

Equivalent Input Noise

-118

dBV

(maximum gain; source resistance 150

ohms; 300 Hz to 20

(ref 1

+ 1, - 3

kHz)

kHz)

dB

practic-

Voltage Gain (ref 1

Headphone

Input Impedance

Mic

Line

Mic

Line

Lo-Z

Hi-Z

kHz)

Impedance

4 ohms total (8 ohms
per earphone, parallel)

1 k total (2k per

phone driver, parallel)

ear-

Gain

70
20
96dB
46

Total Harmonic Distortion

Less than 1% (40 Hz to 15

kHz;

measured at 10

below clipping point)

Input Clipping Levels

Mic Input: 200 mV (-14
Line Input:

60V (

(at 1

kHz)

dBV)

+35 dBV)

Output Clipping Levels

Lo-Z: 750 mV ( -2.5

dBV)

(load resistance 4 ohms

total; 8 ohms per earphone driver, parallel)

Hi-Z:

15V ( +

23

dBV)

(load resistance 1 k total; 2k

per earphone driver, parallel)

Input Impedance (ref 1 kHz)

Mic:

7.5 kilohms

Line: 66 kilohms

Output Impedance

Lo-Z: 16 ohms
Hi-Z: 440 ohms

±10%
±10%

(ref

1

±10%

±10%

kHz)

Phase

Input in phase with output. Pin 2

of Mic Input in phase
with Phones (both phone jacks and mini jacks) tip
and ring

Protection

Protected against damage from

to 5V [ + 14

dBV]

input signals)

shorted outputs, (up

Power

Type: 9V alkaline battery
Battery Life: Approximately 10 hours under normal

operating conditions

mAdc

Current Drain (typical): 6

(idle); 72

(clipping)

Temperature Range

Operating:
Storage:

-29° to

49°C (32°

74°C ( -20°

to

to

120°F)

165°

F)

0° to

Connectors

Input/Output

Locking

3-socket

XLR, Locking

3-pin

XLR,

3-circuit

phone jacks (2)

dB
dB

dB

dB

mAdc

Copyright 1985,
27A8072

(EH)

Shure

Brothers Inc.

Headphones Output:

Phone jack (2)
Mini Jack (2)

Battery Test

Insulated tip jacks;
(

negative)

red (positive) and black

Case

Die-cast zinc; matte black enamel

Overall Dimensions

mm x 150 mm x 55.5 mm

80.9

(3-3/16

x

5-11/16

x

2-3/16

in.)

Net Weight

501 grams (1 lb

2-1/2

oz)

CONTROLS, CONNECTORS, INDICATOR
Level

Control

:

applies power to FP12 circuitry and
sets headphone output level. Knob position also in­dicates when power is applied.

Mic-Line

Switch:

selects microphone- or line-level sig-

nal source.

Hi-Z/Lo-Z Switch:

selects operation with

high­impedance (greater than 600 ohms) or low-impedance
(less than 600 ohms) headphones.

In/Out

XLR and Phone Jacks:

provide loop-through in-

put and output connections for balanced microphone-or

line-level signal sources.

Phones A, B

Jacks:

provide for connection to high- or

low-impedance headphones. Note that A and B head­phone jacks can be used simultaneously. Each output
can accept a headphone phone plug

Batt Test

Jacks:

can be used to check condition of

or

mini plug.

9V

battery.

Connections

Connect the signal source (microphone- or line-level)
to the appropriate
jack), and set the
signal

In/Out

connector (XLR or phone jack) to the input

In/Out

Mic-Line

connector (XLR or phone

switch. Connect the parallel

of mixer, tape recorder or amplifier. Connect the head-

phones (one or two units) to the

set the Hi-Z/Lo-Z switch to the proper position for

Phones A, B

jacks, and

high-

or low-impedance headphones.

Operation

Position the FP12 for operation. Note that the belt
clip can be used to secure the unit to a belt, trousertops,
or D-rings on other equipment. The belt clip can easily

be removed if desired.

Rotate the Level control from the Off position to the

desired listening level. Note that the exposed color dot
on the

Level

control knob serves as a reminder that the

unit is on.

Battery voltage can be checked at any time without

removing the battery or turning the unit on. Inserting

voltmeter leads in the Batt Test jacks (observe proper

polarity) will indicate battery condition.

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.

OPERATION

Battery Replacement

Use a coin or screwdriver, turning one-quarter turn in

either direction, to open the battery compartment door.

Insert a fresh 9V alkaline battery

(NEDA 1604A,

Duracell
MN1604, Eveready 522, or equivalent) in the compart­ment. Note that the battery contacts are polarized, and
the battery cannot be inserted improperly. The compart­ment door can be closed by pressing shut with the
fastener properly aligned.

SHIPPING INSTRUCTIONS

Carefully repack the unit, have it insured, and return it

prepaid to:

Shure Brothers Incorporated
Attention: Service Department
222 Hartrey Avenue
Evanston, Illinois 60202-3696

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.

REFERENCE

DESIGNATION

DESCRIPTION

SHURE PART NO. OR

COMMERCIAL ALTERNATE

BT1
Cl0
C12,

C17
C14, C16
C19
C20
C22
J1-J2
J3,

J5
J4, J6
J7
J8
J9

J10

L1-L8

Battery, Alkaline,
Capacitor, Electrolytic, 4.7
Capacitor, Electrolytic, 10
Capacitor, Electrolytic, 0.47
Capacitor, Electrolytic, 1000
Capacitor, Electrolytic, 2200
Capacitor, Electrolytic, 220

9V

mF,

25V

pF, 16V

pF, 50V

pF, 16V
pF, 16V

pF, 10V

Phone Jack, Stereo Switching
Phone Jack, Stereo Switching
Miniature Phone Jack, Stereo Switching, 3.5 mm
Terminal, Battery Test, Red
Terminal, Battery Test, Black
Connector,

Connector,

3-Socket

3-Pin

XLR, In

XLR, Out

Ferrite Bead Ring

Duracell MN1604
Nichicon

UKB1E4R7KAA
CDE PC10-25
None
Mallory 1000S16
Nichicon
Nichicon 1A221

1C222MRA

MAA
Radio Shack 274-282
None
None
Alco

TBA-2

Alco

TBA-0

Cannon XLR-3-31
(Shure

Cannon
(Shure

95A8060)

XLR-3-32-F77

95A8061)

-F77

Stackpole 57-0181
(Shure

80A250)

Shure

MP1
MP2
MP3
Q1

Belt Clip (without screws)
Control Knob, Level
Circuit Access Cover (without belt clip)
Transistor, Silicon, NPN

53A1891

Shure

65B1533

Shure

32B678

Motorola

2N5210

(Shure

RKC89*)

Q2

Transistor, Silicon, PNP

Motorola
(Shure

R24
S1
S2
S3
T1
T2

U1

200k,

Potentiometer,

Level

Switch, SPST, part of R24

Z/Lo

Switch, Slide, DPDT, Hi
Switch, Slide, DPDT,

Mic/Line

Z

Transformer, Input
Transformer, Output

Integrated Circuit, Dual Operational Amplifier

None

-

None
Shure
None
None

Raytheon

(Shure

U2

Integrated Circuit, Audio Power Amplifier

National

(Shure

Parts listed as “None” should be ordered from Shure Brothers Inc. listing product model number, reference designation, and part description.
*Supplied in multiples of four only.

2N5088

86A348)

55A8020

RC4559NB

86A811)

LM386N-4

86A8818A)