ProDI™ Using & Applications

This short guide is written for those who are experienced with pro-audio and direct boxes. Complete details about the many features built into the ProDI and information about connecting it to your system can be found in the manual (PDF download).

The best feature of the ProDI is its 'plug & play' ease of use. All you do is connect the instrument to the ¼” input, the ¼” through jack to the stage amplifier (if there is one) and the XLR output to the PA or recording mixing console and you are done. Any distortion? Hit the -15dB pad. Any noise? Just depress the ground lift switch to engage the transformer isolation.


You will find that with acoustic guitars and basses, the natural tone of the instrument will shine through with a smooth and musical rendering. For electrically powered devices such as keyboards, the ProDI will immediately eliminate troublesome ground loops while delivering solid dynamics with a full rich sound.

Using the -15dB PAD

Sometimes the output level of active pickups and devices like keyboards can be too hot for audio devices down stream in the signal chain. To prevent distortion the PAD switch introduces a
-15dB attenuation at the instrument input.

Start with the PAD switch in the outward position (disengaged) when doing your basic connection. If you detect distortion engage the PAD by pushing the switch inward. You may have to increase the gain at the console or preamp to compensate.

Using the Ground Lift

As mentioned, the ProDI features 100% transformer isolation to protect against hum and buzz caused by ground loops. If you hear hum or buzz set the lift switch to the inward position.

Setting the switch to the inward position will disconnect signal ground at pin-1 on the XLR connector and allow the transformer to act as a bridge between the input and output.

ProDI with an Electric Bass

Radial ProDI with an Eledtric Bass

The ProDI works great for high output devices like active bass guitars. It is able to handle the huge signal levels from active pickups without distortion and the transformer isolation pevents ground loop hum. The ProDI sends the pure sound of the bass to the PA and to the player's amp.

ProDI with an Acoustic Guitar

Radial ProDI with an Acoustic Guitar

Acoustic guitars can sometimes have sharp sounding active preamps. The ProDI naturally smoothes out the transients for a warmer tone. And because the ProDI is able to handle loud signals from active piickups, it will not distort. This makes it a great direct box for acoustic guitars.

ProDI with a Keyboard

Radial ProDI with a Keyboard

Today's digital keyboards are not only very dynamic, they also have a tremendous range from low to high notes. The ProDI is able to withstand excessive signal levels at all frequencies without introducing distortion or phase shift so all your patches sound great.