Audio Technica UniPoint AT857AMa, UniPoint AT857AMLa Product Information

Description

The AT857AMa is a wide-range condenser
microphone designed for quality sound rein­forcement, professional recording, television,
and other demanding sound pickup applications.
Standing 12.21" above the mounting surface,
its small-diameter alternating gooseneck
design permits highly flexible positioning
while maintaining a smooth, well-contoured
appearance. The AT857AMLa is a 19" version
of this microphone.

Supplied as a cardioid, the AT857AMa easily
accepts interchangeable elements to permit
selection of angle of acceptance from 100° to
360°. The following optional elements are
available from an authorized Audio-Technica
dealer or the A-T service department:
AT853H-ELE hypercardioid, AT853O-ELE
omnidirectional, AT853SC-ELE subcardioid.

The microphone features a 9.8' (3.0 m)
permanently-attached miniature cable with a
3-pin TA3F output connector. It can be pow­ered from an external 9V to 52V DC phantom
power supply or from a 1.5V AA battery.
Current demands are so low that a premium
battery will provide about 1200 hours of
continuous use. A built-in 3-position switch
on the power module allows selection of off,
on/flat response or on/low-roll-off.

Audio-Technica design engineers have
utilized the newest low-mass technology in
the quest for superior performance. The
permanent charge is now on the fixed back
plate, rather than the moving element. With
A-T fixed charge “back plate” construction, a
gold-vaporized diaphragm just 2 microns
thick (or about 0.000079") can be used. This
reduces moving mass, thus improving
frequency response and transient response
while reducing distortion.

The microphone element is enclosed in a
rugged housing with a low-reflectance black
finish. A 5/8"-27 threaded flange allows the
microphone to mate with the threads of a
standard microphone desk or floor stand. A

5

/8"-27 threaded stud is also provided so it can

be secured to a permanent mounting surface.

Installation and Operation

To install the battery, remove the cap from
the top of the power module. Insert the
battery, being certain to observe battery
polarity as marked (+ end toward the cap
release button). For longest battery life, the
switch should remain off except when the
microphone is in use. While standard carbon­zinc AA batteries will operate the microphone
satisfactorily, alkaline or mercury cells are
preferred for longer service life. Only
“leakproof” batteries should be used. The
battery does not have to be in place to use in
phantom power mode. Phantom power
requires 9V to 52V DC.

Output is low impedance balanced. The
output connector of the power module
mates with XLRF-type cable connectors. The
balanced signal appears across Pins 2 and 3,
while the ground (shield) connection is Pin 1.
Output is phased so that positive acoustic
pressure produces positive voltage at Pin 2,

in accordance with industry convention.
The AT8102 two-stage foam windscreen

simply slips over the head of the micro­phone, effectively reducing wind noise or
“popping” when used extra close.

The small-diameter gooseneck is easy to
manipulate for proper positioning. Heavily
lubricated, it operates smoothly and quietly.
Should the unit become noisy with prolonged
use, apply a light machine oil directly on the
gooseneck area affected.

While a modern condenser microphone is
not unduly sensitive to the environment,
temperature extremes can be harmful. Avoid
leaving the microphone in the open sun or in
areas where temperatures exceed 110° F
(43° C) for long periods of time. Extremely
high humidity should also be avoided.

Architects and Engineers Specifications

The microphone shall be a fixed-charge
condenser with a cardioid polar pattern and a
frequency response of 30 Hz to 20,000 Hz. It
shall be capable of accepting optional inter­changeable elements for additional polar
patterns. It shall operate from an external 9V
to 52V DC phantom power source or, alterna­tively, from a 1.5V AA/UM3 battery. Nominal
open-circuit output voltage shall be 6.3 mV
(phantom) or 5.6 mV (battery) at 1 kHz, 1
Pascal. Output shall be low impedance
balanced (200 ohms-phantom, 270 ohms­battery).

The microphone shall have a permanently­attached 9.8' (3.0 m) miniature cable,
terminating in a TA3F output connector. The
output connector shall connect to a TB3M
jack on a power module. The included power
module shall house the battery, and contain
an off/on/low-roll-off switch. The power
module shall terminate in a 3-pin XLRM-type
connector.

The microphone shall be a small-diameter
alternating gooseneck design, with 12.21"
(310.2 mm) [19.00" (482.5 mm)] overall length.
Head diameter shall be 0.47" (12.0 mm). The
microphone shall include a

5

/8"-27 threaded
flange to mate with the threads of a standard
microphone desk or floor stand. A 5/8"-27
threaded stud shall be provided for perma­nent installation to a mounting surface. The
microphone weight shall be 3.6 oz (103
grams) [4.6 oz (131 grams)], without cable.
Finish shall be low-reflectance black.

The Audio-Technica AT857AMa [AT857AMLa]
is specified.

AT857AMa
AT857AMLa

CARDIOID
CONDENSER
ADAPTER­MOUNT
GOOSENECK
MICROPHONES

Frequency Response

50

LEGEND

500

200100

Frequency in Hertz

12" or more on axis (flat)

Roll-off

2k

1k

10k

20k

5k

10 dB

Response in dB

200 Hz

1 kHz
5 kHz
8 kHz

LEGEND

SCALE IS 5 DECIBELS PER DIVISION

90

60

120

30

150

210

240

270

300

330

180

0

AT857AMa
AT857AMLa

Polar Pattern

AT857AMLa
Dimensions

Audio-Technica U.S., Inc., 1221 Commerce Drive, Stow, Ohio 44224
Audio-Technica Limited, Old Lane, Leeds LS11 8AG England

Form No. 0310-0793-08-B/W P50876-01 © 1998 Audio-Technica U.S., Inc. Printed in U.S.A.

0.47"

12.0 mm

1.39"

35.2 mm

310.2 mm

12.21"

30.0 mm

1.18"

2.6 mm

0.10"

0.42"

10.5 mm

AT857AMa/AT857AMLa SPECIFICATIONS

†

ELEMENT Fixed-charge back plate

permanently polarized condenser

POLAR PATTERN Cardioid (Unidirectional)
FREQUENCY RESPONSE 30-20,000 Hz
LOW-FREQUENCY ROLL-OFF 80 Hz, 18 dB/octave
OPEN CIRCUIT SENSITIVITY PHANTOM –44 dB (6.3 mV) re 1V at 1 Pa*

BATTERY –45 dB (5.6 mV) re 1V at 1 Pa*

IMPEDANCE PHANTOM 200 ohms

BATTERY 270 ohms

MAXIMUM INPUT SOUND LEVEL PHANTOM 135 dB SPL, 1 kHz at 1% T.H.D.

BATTERY 121 dB SPL, 1 kHz at 1% T.H.D.

DYNAMIC RANGE (TYPICAL) PHANTOM 108 dB, 1 kHz at Max SPL

BATTERY 94 dB, 1 kHz at Max SPL

SIGNAL-TO-NOISE RATIO

1

67 dB, 1 kHz at 1 Pa*

SWITCH Off, on-flat, on-roll-off
BATTERY TYPE Use only “leakproof” AA/UM3 1.5V battery
BATTERY CURRENT 0.4 mA typical
BATTERY LIFE 1200 hours (alkaline battery)
PHANTOM POWER REQUIREMENTS 9-52V DC, 2 mA typical
WEIGHT MICROPHONE (AT857AMa) 3.6 oz (103 grams)

(AT857AMLa) 4.6 oz (131 grams)

POWER MODULE 5.2 oz (147 grams)

DIMENSIONS MICROPHONE (AT857AMa) 12.21" (310.2 mm) long above mounting surface

(AT857AMLa) 19.00" (482.5 mm) long above mounting surface
(BOTH) 0.47" (12.0 mm) head diameter

POWER MODULE 3.27" (83.0 mm) H x 2.48" (63.0 mm) W x

0.87" (22.0 mm) D

OUTPUT CONNECTOR (POWER MODULE) Integral 3-pin XLRM-type
CABLE 9.8' (3.0 m) long (permanently attached to

microphone), 0.10" (2.6 mm) diameter,
2-conductor, shielded cable with TA3F output
connector that mates with TB3M jack on
power module

ACCESSORIES FURNISHED AT8102 two-stage foam windscreen;

AT8531 power module; battery;
AT8425 5/8"-27 threaded mounting stud

OPTIONAL INTERCHANGEABLE ELEMENTS AT853H-ELE hypercardioid (100°)

AT853O-ELE omnidirectional (360°)
AT853SC-ELE subcardioid (170°)

†

In the interest of standards development, A.T.U.S. offers
full details on its test methods to other industry
professionals on request.

* 1 Pascal = 10 dynes/cm

2

= 10 microbars = 94 dB SPL

1

Typical, A-weighted, using Audio Precision System One.

Optional Accessories:

• AT8104a metal lockable windscreen.

• AT8117 large foam windscreen.

• AT8314 2-conductor, shielded, vinyl-jacketed,
broadcast-type cable with XLRF-type
connector at microphone end, XLRM-type
connector at equipment end. Available in
10', 20', 25', 30', 50' & 100' lengths.

• AT8416 shock mount.

• CP8201 line matching transformer
(Lo-Z to 50,000 ohms).

• CP8506 four-channel 48V phantom power
supply (AC powered).

• AT8801 single-channel 48V phantom power
supply (AC powered).

POWER MODULE

AT8531

audio-technica

MADE IN JAPAN

OFF

PUSH

3.27"

83.0 mm

2.48"

63.0 mm

22.0 mm

0.87"

SWITCH

Roll-off

Flat

Off

Push Button

To Release Cap

AT8531 Power Module

One-Year Limited Warranty

Audio-Technica microphones and accessories purchased in the U.S.A. are warranted for one year from date of purchase by
Audio-Technica U.S., Inc. (A.T.U.S.) to be free of defects in materials and workmanship. In event of such defect, product will
be repaired promptly without charge or, at our option, replaced with a new product of equal or superior value if delivered to
A.T.U.S. or an Authorized Service Center, prepaid, together with the sales slip or other proof of purchase date.

Prior approval from A.T.U.S. is required for return.

This warranty excludes defects due to normal wear, abuse, shipping
damage, or failure to use product in accordance with instructions. This warranty is void in the event of unauthorized repair
or modification.

For return approval and shipping information,

contact the Service Department, Audio-Technica U.S., Inc.,

1221 Commerce Drive, Stow, Ohio 44224.
Except to the extent precluded by applicable state law,

A.T.U.S. will have no liability for any consequential, incidental,
or special damages; any warranty of merchantability or fitness for particular purpose expires when this warranty
expires.

This warranty gives you specific legal rights, and you may have other rights which vary from state to state.

Outside the U.S.A., please contact your local dealer for warranty details.

AT857AMa

Dimensions

1.39"

35.2 mm

30.0 mm

1.18"

2.6 mm

0.10"

0.42"

10.5 mm

0.47"

12.0 mm

19.00"

482.5 mm