Radial PZ-Pre Acoustic Instrument Preamp

In Electronics, Image by jtkung

I recently was looking for a good DI pedal for some electric guitars that have piezo pickups in them but with no preamp (i.e. passive).  I was getting a pretty good sound out of them into a solid-state amp (which probably has a high input impedance), but I wanted something that had a buffer and maybe some EQ capabilities. Not to mention accepting multiple inputs which would obviate the need to buy an extra mixer.

I originally looked at the Fishman Aura Spectrum, but after reading reviews and looking at its features and price, I decided that this unit is really dedicated to imaging of pure acoustic guitars which had piezos or some other passive type pickup, and is not as well suited to piezo-equipped solid-body electrics.

After some research, I discovered the Radial Tonebone PZ-Pre Acoustic Instrument Preamp.   I am amazed at how many features are packed into this floor pedal.   Features list includes:

  • Two switchable inputs, each with a switchable high-impedance piezo buffer
  • Level controls for each input
  • EQ, with parametric EQ on the mids
  • Switchable low pass (bypass, 80, or 200 Hz)
  • Notch filter for feedback
  • Mute switch for all outputs except tuner out
  • Effects loop
  • Boost switch which can be set for either boost, effects loop, or both
  • Boost level
  • Phase reversal
  • 2 XLR outs for pre and post EQ/effects loop
  • Instrument out (to amp)

The coolest feature I have found is the ability to take a stereo cable input to input 1 (a standard 1/4″ TRS cable) which contains two signals (a magnetic output and piezo output), and automatically split them inside the unit to the inputs.  No need to split the stereo cable to mono and use input 1 and 2.   The separate level controls allow you to set the volume levels for matching. There’s also a blending option which mixes both inputs 1 and 2 — a nice addition if you want to blend a mag sound with a piezo.

The only downside is that the EQ is shared for both inputs. Having 2 sets of EQ would have been nice, but would have made the pedal more expensive and much larger and unwieldy.  It would have been nice to be able to bypass the EQ on either channel, however, so that adjustments could at least be made on one of the inputs while the other was bypassed.   Some people have also complained about the external power supply which outputs 15V. This is certainly a possible reliability issue, but not an issue for a studio. On the road, I’d get a backup or some extra AC adapters to mitigate any risk.

But these are small issues in the overall features list.

Soundwise, this preamp is incredible. Very low noise with crystal clear highs and stunning mids and lows. The entire spectrum seems to be enhanced with both the magnetic and piezo pickups.  The mags sound slightly brighter and clearer, and I suspect the buffering that is going on helps as the pickups don’t get loaded down by cabling and all the true bypass circuits in my pedalboard. Those pedals are now in the buffered effects loop.

Overall, this is a valuable addition for any performer who uses two instruments onstage and needs to switch between them, while providing a clear and hot signal to both the FOH or stage monitor/amp.  Radial have really thought this product through, and it shows in both the features list and usability — not to mention their trademark roadworthy metal construction.  Highly recommended!


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