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Source Audio’s ZIO Analog Front End + Boost packs four preamp circuits into one powerful tone-sweetening stompbox

Source Audio has unveiled the ZIO Analog Front End + Boost, a tone-sweetening pedal boasting a quartet of distinct preamp circuits that can hit your guitar amplifier hard with +20dB of boost.

Designed in collaboration with with SHOW Pedals’ Christopher Venter, ZIO is atypical for Source Audio, in that it is all-analogue, but like its digital siblings, it presents players will an abundance of options for enhancing your electric guitar tone.

The pedal has a dial for controlling Output and a four-way rotary Circuit dial for selecting the preamp circuit. 

Choose from the wholly transparent JFET, Low-Cut for tighter low-end and extended headroom, Studio for a “Pultec Trick” inspired voicing that cuts frequencies to clean up the midrange, and E-Plex, which, as the name suggests, replicates the sweet and warm tone mojo from vintage tape echo preamps. The latter will give you a nice bit of grit.

Source Audio ZIO Analog Front End + Boost

(Image credit: Source Audio)

There is also a three-way Tone toggle switch which allows you to select between Dark, Medium and Bright modes, each voiced to replicate the capacitance from different cable lengths – i.e. your Dark mode will sound like you have all the extra capacitance of a long cable length eating some of the treble from your sound. 

And there is a Bypass/Mute toggle switch completing the ZIO’s front-mounted controls, allowing you to use the footswitch as a bypass or as a mute switch.

ZIO can be placed in a number of positions in the signal chain depending on what you want from it. It can be placed before or after your drive pedals, at the end of the signal chain to compensate for long cable runs, or in your amp’s effects loop should you want to match levels between channels or push the power amp harder.

Circuit geek cork-sniffers can rest assured that Source Audio performed its due diligence when seeking out components, and opted for 14-legged Burr Brown op-amps for its “pure tonality, dynamic range, frequency response, and overall feel”. Good to know. 

Zio is true bypass, has an extra tuner/line out, and takes a 9V centre negative power supply. It’s priced £/$199 street and is available now. See Source Audio for more details. 

Jonathan Horsley

Jonathan Horsley has been writing about guitars since 2005, playing them since 1990, and regularly contributes to MusicRadar, Total Guitar and Guitar World. He uses Jazz III nylon picks, 10s during the week, 9s at the weekend, and shamefully still struggles with rhythm figure one of Van Halen’s Panama.