Lectrosonics UH400a - Manual (Page 6)

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UH400A/UH400TM
Controls and Functions
MODULATION LEDS
PHTM
NO PHTM
PWR OFF LEVEL 15V
48 V
5V
POWER
ON/OFF
LED
INPUT
JACK
MIC LEVEL
Top View Control Panel
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This transmitter may be used with a wide variety of mi­
crophones. The 3-pin XLR connector allows the trans­
mitter to be used with any dynamic microphone, as well
as many two wire positive bias lavaliere systems (such
as those supplied by Lectrosonics).
Power Switch
The three position switch turns the unit on or off, and
selects either phantom power, or no phantom power.
Regardless of which position the switch is set, the pilot
tone muting system effectively prevents “thumps” or
transients from occurring during power up or power
down.
The PHTM (center) position of the power switch turns
on the phantom power value selected by the Phantom
Power Voltage Select switch, while the NO PHTM (fully
on) position disables phantom power.
Note: In order to avoid damage to some
microphones, be careful to use the center (PHTM)
position only when necessary and keep the
Phantom Power Voltage Select switch in the 5
V position. (See Phantom Power Voltage Select
switch.)
Power ON/OFF LED
This LED glows green when the battery is good. When
the lamp glows red, there will be about 20 minutes of
battery life left with an alkaline battery. The lamp will
blink red when there are only a few minutes of life re­
maining.
Note: A NiMH battery will give little or no warning
when it is depleted. If you wish to use NiMH
batteries in this unit, we recommend installing a
fully charged batteries, noting the length of time
that the batteries will run the unit and in the future
use somewhat less than that time to determine
when the battery needs to be replaced.
A weak battery will sometimes light the POWER LED to
the “good” green indication immediately after being put
in the unit, but will soon discharge to the point where the
INPUT FREQUENCY SWITCHES
JACK (BEHIND DOOR)
POWER
SWITCH
PHANTOM POWER
1.6MHz 100kHz
0 1 2 3
4
5 6
F
7 8 9 A B C D E 0 1 2 3
4
5 6 7 8 9 A B C D E F
1.6MHz 100kHz
FREQUENCY
VOLTAGE SELECT
Side View
LED will go red or shut down (just like a flashlight with
“dead” batteries). If the Power LED fails to light when
power is applied, replace the battery.
Phantom Power Voltage Select Switch
Note: The UH400TM can be used with the
Earthworks M30 Test Microphone if pins 2 and 3
are reversed. A barrel adapter is provided for this
purpose.
This switch selects from three phantom voltages when
the PWR switch is in the mid position. The voltages are:
• 5 Volts for lavaliere microphones,
• 15 Volts for some professional mics requiring high
current and for many common stage mics that will
operate over a wide phantom Voltage range of 12 to
48 Volts. With the proper adapter, this position can
also be used with T power microphones. See our
web site for details on finding or making the proper
adapter.
• 48 Volts for microphones that do in fact require a
supply greater than 18 Volts. (See below for a dis­
cussion of why 42 and not a “true” 48 Volts.)
For longest battery life use the minimum phantom volt­
age necessary for the microphone. Many stage micro­
phones regulate the 48 Volts down to 10 Volts internally
anyway, so you might as well use the 15 Volt setting and
save some battery power. If you are not using a micro­
phone for the input device, or are using a microphone
that does not require phantom power, set the Power
Switch to the NO PHTM position (No Phantom Power).
This is the fully up position of the Power Switch. Phan­
tom power should only be used with a fully floating,
balanced device such as most microphones with a 3-pin
XLR connector. If you use the phantom power with an
unbalanced device or if pins 2 or 3 are DC connected
to ground, then you will draw maximum current from the
power supply. The UH400A is fully protected against
such shorts but the 9 Volt battery will be drained at
twice its normal rate.
LECTROSONICS, INC. 6