The Source Audio Zio is an all-analog preamp and boost pedal, and it marks a departure for its maker. Source Audio is best known for its forward-thinking digital effects pedals, but the Zio is the company's first all-analog effects pedal, designed in collaboration with Christopher Venter, the owner and sole engineer at SHOE Pedals1. According to GuitarPlayer, digital-circuitry supply chain issues led the team to speed up the release of this first analog collaboration1. It carries a list price of $2492.
The idea behind it is simple, as Source Audio puts it: "make everything sound better." The pedal offers four distinct preamp circuits, each capable of up to +20dB of additional output boost, so a player can use it as a clean volume lift, a tone-shaping front end, or both3. GuitarPlayer's reviewer described it as "more than a conventional booster," and gearnews characterized it as "a kind of Buffer / Preamp / Booster all in one"45.
The Zio family has two versions: the ZIO Analog Front End + Boost for guitar, and the ZIO Analog Bass Preamp + DI for bass, which adds a balanced XLR direct output. Both are listed as sold out on Source Audio's product pages as of October 202636.
Four preamp circuits and the controls
The core of the pedal is a Circuit switch that selects one of four discrete preamp circuits: JFET, Low-Cut, Studio, and E-Plex3. Each voicing can push up to 20dB of boost through the Output knob7. The circuits use an all-original design, and the pedal is built around Burr-Brown SoundPlus op amps, which Venter and Source Audio chose for their dynamic range, frequency response, and feel31. Source Audio says the high-fidelity, noise-free op amps give the Zio "extreme clarity and responsive pick dynamics"3.
| Control | What it does |
|---|---|
| Circuit switch | Selects one of four preamp circuits: JFET, Low-Cut, Studio, E-Plex83 |
| Output knob | Up to +20dB of signal boost3 |
| TONE switch (Bright/Med/Dark) | Three capacitor stages simulating different cable lengths, to brighten or darken the guitar's sound4 |
| Footswitch | Can be set to bypass or to mute for tuning1 |
Of the four circuits, the maker describes Low-Cut as reducing "tubby" bottom-end for a tighter sound with added headroom3. The TONE switch is a distinctive touch: gearnews describes its Bright/Med/Dark positions as three different capacitor stages that simulate different cable lengths, letting a player brighten or darken the sound of the guitar itself4.
Notably, the Zio does not use Source Audio's Neuro editing system. GuitarPlayer notes it is the first, and so far only, pedal in the line to skip Neuro, sticking with standard surface controls instead1. Everything is dialed in on the pedal itself.
Two outputs and the tuner mute
The guitar version has a standard input and two standard outputs: Main and Tuner/Line Out8. A switching option mutes output one while sending the signal to a tuner connected to output two, which allows silent tuning or guitar changes14. For a player running a tuner off the side of their board, this removes the need for a separate mute box.
The bass version: ZIO Analog Bass Preamp + DI
Source Audio later extended the Zio to bass with the Analog Bass Preamp + DI, an ultra-low-noise, all-analog tone-shaping pedal that works equally well in front of an amplifier or as a preamp and direct box via its balanced XLR output6. Guitar World reported on it in January 2024, pricing it at $249 and noting its 4x3-inch scale should sit snugly on most pedalboards2.
Where the guitar version's boost reaches +20dB, the bass version's OUTPUT knob offers up to +16dB of overall boost above unity gain, or up to -6dB of cut63. Its connections differ too:
- DIRECT OUT: a balanced XLR output with a ground LIFT switch, delivering what the maker calls a low-noise, yet amp-like signal6
- Standard 1/4-inch output: allows a parallel signal to a pedalboard or bass amp6
- Bass & Treble EQ: Bass Musician Magazine's reviewer called it "musical and responsive," thickening the low end and adding top-end sparkle9
- Grit toggle: adds a touch of saturation9
Bass Musician Magazine's Cláudio Ribeiro found the EQ never felt heavy-handed, and that the Grit toggle, while not aggressive, "adds a pleasing touch of saturation that rounds out transients"9. His overall take on its character:
"Clean. Clear. Tight. This is a pedal for players who want their bass to sound like their bass, just better."
Nate Navarro, quoted by Guitar World, called the Zio pedal "an all-analog, tone-shaping machine" that packs "great features"2.
What the reviewers said
GuitarPlayer's reviewer used the Zio at the beginning of the signal chain to restore tone lost through pedals and a laptop, and after drive pedals for beefier solos with more sustain1. The magazine's verdict summed it up as a "versatile, powerful, clean boost that you can color or not, to taste," with no reasons to avoid listed1. Guitar World's Trevor Curwen listed the "massive 20dB boost" among the pedal's pluses8.
gearnews called it "a well thought out design with some good tonal choices," calling it an invaluable tool for players who work with various setups or do a lot of live work4.
Where it came from and where it is made
The Zio is Source Audio's first all-analog pedal, designed with Christopher Venter of SHOE Pedals, and its release was sped up because of digital-circuitry supply chain issues1. It is priced at $2492. Both the guitar and bass versions are currently shown as sold out on Source Audio's own product pages36.
For more on pedals in this category, see the boost pedals and preamp pedals pages, or the bass pedals page for the bass version's territory.
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Questions
Does the Source Audio Zio use the Neuro app?
No. The Zio is the first, and so far only, pedal in the Source Audio line to skip the Neuro editing system. All of its voicings and settings are handled on the pedal itself with the Circuit switch, Output knob, and Tone switch, so there is nothing to edit from a phone or computer.
Is the Source Audio Zio analog or digital?
It is all-analog. Source Audio is best known for its digital effects pedals, but the Zio is the company's first all-analog effects pedal, built around Burr-Brown SoundPlus op amps chosen for their dynamic range, frequency response, and feel. It was designed with Christopher Venter of SHOE Pedals.
Can the Zio be used as a DI for bass?
Yes, in its bass-specific form. The ZIO Analog Bass Preamp + DI has a balanced XLR direct output with a ground lift switch, so it works as a preamp and direct box straight to a mixing desk, as well as in front of a bass amp. The guitar version, the Analog Front End + Boost, has standard 1/4-inch outputs instead.
Who designed the Source Audio Zio?
The Zio was designed in collaboration with Christopher Venter, the owner and sole engineer at SHOE Pedals. It is Source Audio's first analog collaboration with him, and according to GuitarPlayer, digital-circuitry supply chain issues led the team to speed up its release.
What is the difference between the Zio Analog Front End + Boost and the Bass Preamp + DI?
The Analog Front End + Boost is the guitar version: four preamp circuits (JFET, Low-Cut, Studio, E-Plex), up to +20dB of boost, and standard main plus tuner/line outputs. The Analog Bass Preamp + DI is built for bass, with Bass and Treble EQ, a Grit toggle, up to +16dB of boost or -6dB of cut, and a balanced XLR direct output with ground lift.
Where is the Source Audio Zio made?
Both Guitar World and GuitarPlayer list the Zio's origin as China. It comes in a compact 4x3-inch enclosure with a brushed anodized aluminum housing and a dark green finish, so it fits easily on most pedalboards.
Sources (9)
- Source Audio Zio Booster Pedal Review, GuitarPlayer (www.guitarplayer.com), 2022-07-12
- “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, Guitar World, 2024-01-10
- ZIO Analog Front End + Boost, Source Audio
- Zio Analog Front End + Booster, gearnews.com, 2022-01-13
- source audio zio boost pedal review, Premier Guitar, 2022-05-13
- ZIO Analog Bass Preamp + DI, Source Audio
- Source Audio ZIO Analog Preamp/Boost, Delicious Audio, 2024-01-09
- Source Audio ZIO Analog Front End + Boost, Guitar World, 2022-06-10
- Gear Review: Source Audio ZIO Bass Preamp + DI, Bass Musician Magazine, 2025-05-19
