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PZ-Select™ USING & APPLICATIONS

The Radial PZ-Select is 'almost' plug and play easy to use. To take full advantage of the PZ-Select's feature set, there are a few little bits and pieces that you should be aware of which are described on this page. For full details, feel free to download the manual by clicking the icon at left.

Getting to know the PZ-Select

The PZ-Select is basically a 2-in, 2-out switcher. Channel-1 is optimized for magnetic pickups as usually found on electric guitars while channel-2 has been optimized for piezo transducers which are commonly used on acoustic instruments. This means the PZ-Select is equally effective for musicians that switch between two instruments and for those that employ hybrid guitars that combine electric and piezo pickups in one instrument.

Both channels are buffered. This means that the guitar signal is managed inside the PZ-Select to minimize switching noise while enabling the PZ-Select to drive longer cable distances with less induced noise from magnetic fields and radio frequencies. Channel-1 is equipped with Drag Control load correction. This 'set & forget' control enables you to adjust the load on the pickup to replicate the tone and feel as if connected directly to your amp. Channel-2 features a super-high 10 meg-ohm input impedance that smoothes out the peaks and widens the frequency response of a piezo.

Making connections

As with any system, always make connections with your equipment turned off or levels set to zero. This will avoid turn-on transients that can damage more sensitive components such as tweeters. There is no power switch on the PZ-Select. 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.

When using the PZ-Select with two instruments, each guitar cable is connected to its own ¼" input. When used with a hybrid guitar, a stereo ¼" TRS cable is connected to channel-1 and the PZ-Select will break out the signals. The tip of the connector feeds the electric channel and the ring feeds the acoustic.

Optimizing the signal path

There are three outputs to choose from. Because each of these instruments, amplifiers and PA system are quite unique, each one must be managed differently.

  1. The magnetic (electric) to feed the on-stage guitar amp
  2. The piezo (acoustic) to feed a separate on-stage instrument amp
  3. The XLR balanced output to feed the PA system

The magnetic-electric

Start by connecting the electric pickup output to your stage 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-Select should illuminate and you should hear sound.

To keep the purist happy, the electric (magnetic) signal path is as pure as possible. It employs Radial's award-winning class-A buffering circuit and Drag™ control load correction to deliver the most natural sound right to your amp. Drag™ control replicates the tone and feel as if connected directly to a tube guitar amplifier. Start with the Drag™ control at the 12 o'clock position, using a guitar pick as a screwdriver, and adjust as you see fit. This 'set & forget' control is recessed so that once you have decided on where you like it - your setting will not accidentally get changed.

The piezo-acoustic

For the piezo (acoustic) source, you actually have two outputs to choose from: a hi-Z stage amp output and a balanced lo-Z direct box output. Start by connecting the stage amplifier following the same process as detailed above. 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 transformer coupled so that it can be electrically isolated from the guitar amp on stage. This helps to eliminate buzz and hum caused by ground loops. If after you connect it, you still hear hum or buzz, try lifting the ground connection on the ¼" by moving the top-mounted switch to the up position.

It is important to note that many acoustic instruments have built-in preamplifiers that buffer the signal before it is output from the instrument. If not loaded correctly, this can cause the piezo to sound harsh, peaky and edgy. To compensate, the piezo channel is equipped with two filters. The low-pass filter (high-cut) is used to smooth out and warm the high end when confronted with this type of problem. 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.

When using an acoustic instrument, a major concern is resonant feedback. Powerful low frequencies from the PA system or stage amp cause the top of the instrument to vibrate, which in turn produces uncontrollable resonance at certain frequencies. The high pass filter (low-cut) is used to tame excessive bottom end. Experiment with the three positions to find the one that works best for you.

The Radial direct box

The PZ-Select is equipped with a built-in Radial DI box. It 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: The first is a ground lift that lifts pin-1 at the XLR output connector. This is used to help eliminate hum and buzz caused by ground loops. The second is a 180⁰ polarity reverse. This works with the high-pass filter (low-cut switch) to help eliminate feedback caused by hot-spots on stage. When performing live on stage, sound waves from the stage amp, monitors and PA system come together to create the sound you hear on stage. When certain frequencies are 'in phase', they combine to create frequency bumps which can cause feedback. Reversing the polarity can cause the offending waves to cancel out, which in turn, can help eliminate feedback.

Important note: The 180° polarity switch is recessed as a reminder that it can sometimes cause a popping noise when switched. To avoid popping, always turn the volume level down before switching.

The effects loop

Another cool feature built into the PZ-Select 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 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-Select 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. When directly coupled to a magnetic and piezo pickups, a tuner will introduce secondary load on the pickup which will cause the tone to shift. The quartz tuner chip can also introduce clocking noise in the form of clicking, particularly when used with high gain amps.

To solve the problem, the PZ-Select tuner out is separately buffered. In other words, the signal is managed so that it will not load the pickups or introduce noise.