
How the Pro48 works
The Radial Pro48 is a professional direct box that
is equally useful for studio as it is for performance.
It serves the purpose by converting the high input
impedance of an instrument to the low input impedance
of a microphone level signal. It also balances the
signal to allow long runs upwards to 1000 feet (300
meters) without appreciable signal loss or noise.
Unlike typical direct boxes that simply use phantom
power to drive an internal buffer, the J48 actually
converts phantom power from DC to AC, then uses
a unique digital switching power supply to increase
the internal working voltage in order to achieve
much greater headroom. Because of this process,
the active amplifier (buffer) is not constantly
red lining.
This means we do not have to trade off frequency
response for dynamic range. The result is a response
curve that starts at 10Hz and extends well above
100kHz where most other ‘pro’ direct
boxes are barely able to achieve a response past
15kHz and are completely mud in the low end. This
assures the natural tone of the instrument is
maintained without degradation.
So what does this have to do with using the Pro48?
Simply put – with the Pro48 active direct
box you have less to worry about. Although the
Pro48 is extremely easy to use, there is a ton
of technology built inside that makes it so.
Using the Pro48
1. Begin by making sure the PA system is turned
down before connecting the Pro48. This practice
will assure that transients from powering up the
active circuit do not enter the sound system.
This good safe approach will help keep those tweeters
working for years!
2. Connect the ¼” cable from the
instrument to the Pro48’s input and the
thru connector to the instrument amp or personal
playback system.
3. Connect the XLR cable from the Pro48 to the
mixer. Turn the 48V phantom power on. Today pretty
much all mixers are equipped with 48V phantom
powering. This ingenious system sends a DC signal
back to the Pro48 that powers the internal amplifier
that does not interfere with the AC audio signal
path.
4. Turn the volume up on your mixer – slowly
to a low level and test to make sure signal is
present. If you encounter any buzz or hum, try
lifting the ground.
5. You are now ready to test the audio. Begin
playing. If you encounter any distortion, lower
the source volume or hit the input pad. You are
now good to go! |