“An all-analog tone-shaping machine”: Source Audio and Shoe Pedals team up for the Zio, a preamp and DI pedal designed specifically for bass

Source Audio Zio Preamp
(Image credit: Source Audio YouTube)

Source Audio has announced the release of its all-analog, ultra-low noise bass preamp and DI pedal, the Zio. Specifically designed for bass guitar tone-shaping, the pedal results from a collaboration between Source Audio's lead engineer, Jesse Remignanti and Christopher Venter, the head of Brooklyn-based pedal makers, Shoe Pedals.

It's been designed for ease-of-use, and can be placed on pedalboards, in front of amps, or XLR direct out directly to a front-of-house mix or recording interface thanks to a choice of three independent outputs. A third output choice comes via a dedicated headphone jack.

With Burr-Brown Op-Amps under the hood for “maximum headroom”, alongside offering a clean preamp, there's a simple array of EQ filter controls for nitty-gritty tone-tweaking. These come in the form of controls for output, bass, treble and focus. 

The bass control is said to provide “a substantial low-end boost” at around 100Hz and works to gently reduce any muddy low-mids for clarity. Its focus knob sweeps the cut-off point of a high-pass filter to subdue excessive sub-bass, with a treble control helping enhance articulation or smoothen out its tones. Its output offers up to +16db of boost, or up to -6db of cut.  

These are accompanied by two toggles for grit and scoop, which can be activated independently or simultaneously. The grit vies to capture the sound of a vintage amp pushed into breakup territory. Its grittiness can be adjusted with what Source Audio calls a "set-it-and-forget-it” gain control located out of sight on the side of the pedal.

The scoop toggle, meanwhile, triggers a low-mid cut to clean up overly muddy tones, whilst also kicking in an upper-midrange presence boost so there isn’t an excess of bass-rumbling brown notes.

The feature was intuited to replicate the ‘Pultec Trick’ studio engineers have been using since the ‘50s, where vintage Pultec EQP-1A studio rack units are added to signal chains to offer greater clarity and articulation to the output. It could also prove to be a nifty feature for slap players specifically.

During his review of the pedal (above), Nate Navarro called the Zio pedal "an all-analog, tone-shaping machine” that packs "great features". In the video, the bassist who has played with Porcupine Tree and Devin Townsend, puts the pedal through its cleanest and grittiest paces.

With a 4x3" scale, it should sit snuggly on most pedalboards, with its dark green finish making for a rather snazzy-looking unit. Priced at $249, it sits in the middle bracket price range when compared to other preamp and DI pedals on the market.

For more information, head to Source Audio.

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Phil Weller

A freelance writer with a penchant for music that gets weird, Phil is a regular contributor to Prog, Guitar World, and Total Guitar magazines and is especially keen on shining a light on unknown artists. Outside of the journalism realm, you can find him writing angular riffs in progressive metal band, Prognosis, in which he slings an 8-string Strandberg Boden Original, churning that low string through a variety of tunings. He's also a published author and is currently penning his debut novel which chucks fantasy, mythology and humanity into a great big melting pot.