The following page describes how to use the JDI Stereo for most applications. For complete details, we invite you to download the full manual by clicking the icon at left.

The Radial JDI Stereo is a passive direct box. This means that it does not require any power to make it work. You simply plug in and it will quietly go to work. Further, as the JDI Stereo employs transformers, these naturally block stray DC voltage that can cause system noise. This also means that 48V phantom power as used with condenser microphones will not harm the JDI Stereo.

Making Connections

As with all audio gear, always ensure audio system levels are turned down or equipment turned off before making connections. This will avoid plug-in or turn-on transients from damaging more sensitive components such as tweeters.

There are two channels on the JDI. These are identical, and feature a ¼" INPUT, a ¼" THRU-put and a balanced XLR out. Connect your source instrument to the input and the balanced XLR out to the PA system or recorder. Unbalanced cables are much more susceptible to noise than their balanced counterparts. Keeping unbalanced cables under 8 meters (25') in length is good practice while balanced cables can easily extend 100 meters (300'). The balanced output of the JDI stereo is mic level, meaning that it should be connected to the mic input of a mixing console or mic preamp.

The THRU connector output provides the means for connecting the signal to a stage amp or personal monitor system. Simply connect the THRU to your amp or monitor.

Using the JDI Stereo with a bass and stage amp
Using the JDI Stereo with a keyboard, mixer and powered speakers
Click images to enlarge

Using the -15dB PAD

Inside the JDI Stereo are two high performance Jensen transformers. These can be hit hard with plenty of level without worry. In fact, many artists and engineers enjoy the sound of the JDI when pushed hard as it will exhibit a natural compression when the transformer is pushed towards saturation.

There are however instances when the output from and instrument can be extreme. To prevent from excessive saturation, the JDI Stereo has a -15dB input pad that reduces the input sensitivity. Examples could be a very high output digital piano or maybe the overly aggressive output from a DJ mixer.

Using the Ground LIFT

Passive direct boxes like the JDI Stereo are particularly effective at reducing hum and buzz by so called ground loops. But ground loops manifest themselves in many different ways including induced DC noise into the cable from nearby power supplies or transformers, DC offset voltages from less than ideal electronic designs, or simply a bad electrical supply that is causing havoc.

To further assist, the JDI Stereo is equipped with a ground lift switch that lifts Pin-1 on both XLR connectors at the same time. When the electrical ground and the audio ground conflict, you can encounter noise and simply lifting the audio ground will usually solve the problem