Since launching the Radial J48, it has steadily grown to become a favorite with the professional touring community. Increased headroom, less distortion and the resulting improved sound is a welcome addition to the ever greater demands for sonic purity.

As demands have increased from the professional touring community, awareness has also increased in other markets where customers have been asking for a more affordable version for studios, churches and other performance venues where affordability plays a more important role.

Following the footsteps of the popular Radial J48, the Pro48 presents a pared down solution that is at once affordable yet does not compromise the audio in any way. Cost reduction measures include a smaller footprint, less graphics and reduced feature set, eliminating extravagances such as the merge function (mix) and the high pass filter.

Singly, the most important function of a direct box is to transfer the sound of the instrument to the mixer without coloration. This means that every effort must be made to minimize harmonic distortion while expanding headroom.

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!