The Radial PZ-DI is pretty much ‘plug and play’ easy to use. There are only a few little extras that one needs to be aware of to take full advantage of the PZ-DI’s feature set. The easiest way to understand the PZ-DI is to follow the block diagram:

There are two inputs each of which drives a separate channel: one for the electric (magnetic pickup) and one for the piezo (acoustic pickup).  Because both of the sources are very different, they are treated individually to maximize performance.

Making Connections
As with any system, always make your connections with your equipment turned off or levels to zero. This will avoid transients that can damage speakers. There is no power switch on the PZ-DI. As soon as you connect the 15VDC power supply it will turn on. To check powering, simply depress one of the two footswitches and the LED indicator will illuminate.

Most combination magnetic-piezo guitars have either stereo ¼” TRS output or are equipped with separate ¼” outputs for each pickup type. When you connect to the PZ-DI with a TRS cable, the tip of the connector feeds the electric channel and the ring feeds the acoustic. If your guitar is not set up this way, you simply need to reverse the connections at the output end of your cable to accommodate. The PZ-DI will break out each signal internally and send it to the appropriate channel.

The Magnetic Electric
Start by connecting the electric amp using a standard ¼” cable. Turn the amp on, turn up the volume a bit and test to make sure it works by depressing the electric footswitch. The LED on the PZ-DI should illuminate and you should hear sound.

To keep the purist happy, the electric (magnetic) signal path has been purposely kept extremely clean. We have employed Radial’s award winning class-A buffering circuit and Drag Control load Correction to ensure the most natural sounding and noise free connection delivers you tone to the amp. Set the Drag control to 12 o’clock using a guitar pick as a screwdriver. This ‘set & forget’ control is recessed so that once you have decided on where you like it - your setting will not accidentally get changed.

Drag control basically reintroduces the load on the pickup to replicate how the guitar sounds when connected directly to your amp through a length of cable. Because the PZ-DI is buffered, the signal will likely be too clean if set to full. The 12 o’clock position replicates the sound of a Fender Stratocaster® connected to a tube amp. Try it, it will blow you away.

The Piezo Acoustic
For the piezo (acoustic) source, you actually have two outputs to choose from: the stage amp and the direct box. Start by connecting the stage amplifier following the same process. Testing the signal is again merely a matter of depressing the footswitch, checking the LED to make sure it goes on and then turning up your amp. The piezo output is also transformer coupled so that it can be electrically isolated form the guitar amp on stage. This helps tremendously in eliminating buzz and hum caused by ground loops. If after you connect it, you still hear hum or buzz, this can usually be eliminated by switching the ¼” ground lift switch to the upward position.

The piezo channel is equipped with two filters. The hi-cut or low pas filter is designed to roll off the high end from the piezo as these can often sound harsh or edgy. There are three settings: Start by setting it to bypass (flat) and listen. Then move the switch to the first and second filter set to select the position you find sounds best. The lo-cut or high-pas filter employs the same functionality only this time; it is used to roll off excessive bottom end. This is particularly useful when sending the acoustic signal to a full range PA system.

The built in direct box
The PZ-DI is equipped with a built-in Radial DI box. This DI circuit is similar to the popular Radial J48 in that it is active and able to handle plenty of level without distortion. There are two dedicated slider switches for the direct box: a ground lift that lifts pin-1 at the XLR output connector and a 180º polarity reverse. This switch is recessed as a reminder that it can sometimes cause a popping noise when switched. To avoid popping, always turn the volume levels down before switching. The 180º polarity reverse is used to ‘phase align’ the output going to the PA so that it better mixes with the monitors and stage amp sounds. Sometimes, depending on where you are standing the sound from the PA will interact and make the sound onstage sound strange. Reversing the polarity can help. 

Side note: Using the 180º polarity switch with acoustic guitar can help reduce resonant feedback on stage. This type of feedback is often caused by the stage amplifiers and monitors interacting with the PA system creating ‘hot spots’ called modes on stage. Reversing the polarity will change the phase relationship between the speakers and move the hot spot. This can often help eliminate feedback.

The effects loop
Another cool feature built into the PZ-DI is the effects loop.  This is dedicated to the piezo acoustic channel as a means of adding an effect like reverb or a more radical EQ to the signal path. This way, you can use a TRS cable from your guitar and have the effects routed to both your on stage amp and to the DI box out so that they can be heard on stage and through the PA system for the audience.

For the electric-magnetic signal path, pedals would simply be connected from the electric output before going to the stage amp. The PZ-DI will act as a buffer for the pedals which will quiet them down and allow longer cable runs to 50 feet without appreciable noise.

The Tuner Out
Last but not least is the tuner out. This is a separately buffered output that feeds the tuner with both the electric and acoustic signals at all times. Tuners are known to sometimes cause a faint clicking noise as their quartz chips work away. Because the PZ-DI’s tuner out is buffered, noise from the tuner is blocked.

Using the PZ DI with two instruments
The PZ-DI will undoubtedly find many fans with those that switch between electric and acoustic instruments on stage.  Hook up is no different than described above… just use two instruments with two cables and you are set to go!