Source Audio ZIO Analog Front End + Boost review

This formidable new boost offers up a choice of preamp flavors and is just the sort of super-practical tone sweetener you'd want to superglue to your pedalboard

Source Audio ZIO
(Image: © Future / Olly Curtis)

Guitar World Verdict

Source Audio’s ZIO has a plethora of classy options just waiting to be exploited, whether you choose to use it as an always-on tone conditioner or as an on/off booster. The absolute practicality of having one of these on your pedalboard cannot be overstated.


  • +

    Compact size.

  • +

    Massive 20dB boost.

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    Four preamp options.

  • +

    Adjustable signal brightness.

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    Dual outputs.


  • -

    Cheaper boosts are available, but few are this versatile.

You can trust Guitar World Our expert reviewers spend hours testing and comparing guitar products so you can choose the best for you. Find out more about how we test.

Designed by Source Audio to “make everything sound better”, the ZIO, the company’s first all-analogue pedal, is a preamp/boost pedal that’s capable of up to 20dB of boost via a choice of four different preamp circuits to colour the sound. 

On top of that, it acts as a buffer and has a Tone switch that offers three different levels of capacitance to simulate cable length, allowing you to make your tone brighter or darker. 

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Trevor Curwen

Trevor Curwen has played guitar for several decades – he's also mimed it on the UK's Top of the Pops. Much of his working life, though, has been spent behind the mixing desk, during which time he has built up a solid collection of the guitars, amps and pedals needed to cover just about any studio session. He writes pedal reviews for Guitarist and has contributed to Total Guitar, MusicRadar and Future Music among others.