Digital Plug-On Transmitter
Rio Rancho, NM
13
Selecting the Low Frequency Roll-off
It is possible that the low frequency roll-off point could
affect the gain setting, so it’s generally good practice to
make this adjustment before adjusting the input gain.
The point at which the roll-off takes place can be set to:
• 25 Hz
• 100 Hz
• 35 Hz
• 120 Hz
• 50 Hz
• 150 Hz
• 70 Hz
The roll-off is often adjusted by ear while monitoring the
audio.
.
Input...
Gain
Rolloff
Polarity
Rolloff
70 Hz
Selecting Audio Polarity (Phase)
Audio polarity can be inverted at the transmitter so the
audio can be mixed with other microphones without
comb filtering. The polarity can also be inverted at the
receiver outputs.
Input...
Gain
Rolloff
Polarity
Polarity
Normal
Invert
Selecting Phantom Power Supply
Input...
Rolloff
Polarity
Phantom
Phantom
15V
The transmitter input jack can provide phantom power
for the attached microphone if needed, with voltages
at 5, 15 or 48. Phantom power will consume a slight
amount of battery power, so it can also be turned off.
About the Phantom Power Supply
Three phantom voltages are selectable from the control
panel. 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
discussion 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, turn the phantom
power off.
Phantom power should only be used with a fully float-
ing, balanced device, such as common 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 DPR is fully protect-
ed against such shorts but the batteries will be drained
at twice the normal rate.
The transmitter can supply 4 mA at 42 Volts, 8 mA at 15
Volts, and 8 mA at 5 Volts. The 42 Volts setting actually
supplies the same voltage to a 48 Volt microphone as
the DIN standard arrangement due to a dynamic biasing
scheme that does not have as much voltage drop as the
DIN standard. The 48 Volt DIN standard arrangement
protects against shorts and high fault current with high
resistance in the power supply feeds to pins 2 and 3.
This provides protection if the supply current is acciden-
tally shorted to ground and also keeps the microphone
from being attenuated by the power supply.
The DPR improves on those functions and is able to use
less power from the battery by using constant current
sources and current limiters. With this dynamic arrange-
ment, the DPR can also supply more than twice the
current of competing 48 Volt plug on units and provide
four times the current for some very high end 15 Volt
microphones.
