Source Audio ZIO User manual
SA271 ZIO User Guide
1
ZIO Analog Front End + Boost User Guide
Welcome
Thank you for purchasing the Source Audio ZIO! ZIO is an all-analog preamp/boost pedal that was
designed for those who want to take their tone to the next level. The ZIO is our first all-analog effect
pedal and was a collaboration effort with Christopher Venter of Shoe Pedals. Christopher is a
longtime friend of Source Audio and a true connoisseur of sound. He has previously worked with us
on other projects such as fine-tuning the True Spring Reverb and selecting its core set of sounds, as
well as other successful projects such as the DOD Looking Glass Overdrive.
The word "ZIO" is an acronym for Impedance (Z), Input (I), and Output (O). The goal in creating this
pedal was simple yet ambitious: we wanted to “make everything sound better.” ZIO serves two
primary functions. First, it offers not one, but FOUR distinct preamp circuits that not only boost your
signal level up to +20dB, but also provides four choices of preamp coloring. Second, it acts as a
“buffer that doesn’t sound like a buffer,” and has the capability of restoring volume and high-end loss
from long cable runs and large pedalboards. The TONE switch gives you three different levels of
capacitance (or simulated cable length) to brighten or darken your tone.
The ZIO’s simple control set makes it easy to find the perfect “base tone” for any guitar and ensures
that the dry signal hitting your pedals and amp remains strong and consistent. We hope that you
find the ZIO to be the “better box” for your tone that you have always been searching for.
—The Source Audio Team
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Contents
Welcome ................................................................................................................................................. 1
Contents .................................................................................................................................................. 2
Feature Overview .................................................................................................................................... 2
Connecting the Pedal .............................................................................................................................. 3
Preamp Modes ........................................................................................................................................ 5
Where Do I Put the ZIO? ......................................................................................................................... 8
Controls ................................................................................................................................................... 9
Specifications ........................................................................................................................................ 10
Troubleshooting .................................................................................................................................... 10
Frequently Asked Questions ................................................................................................................. 11
Rubber Feet ........................................................................................................................................... 11
Waste Disposal Notes ........................................................................................................................... 11
Warranty ............................................................................................................................................... 12
Version History ...................................................................................................................................... 13
Feature Overview
Up to +20dB of Clean Boost – Boost your output level heading into your amplifier, interface, FOH, or
other output destination.
True Bypass – The ZIO features true bypass signal path architecture, so it can be run anywhere in
your chain of effects.
Compact Design – The extruded anodized aluminum housing, with its slim profile and small footprint,
is built for the rigors of the road.
Four Discrete Analog Circuits – Select between four unique circuit designs, perfectly tuned for
maximum performance.
Cable Capacitance Selector – Recreate three different sized loads of capacitance with the bright-to-
dark TONE switch
Flexible Bypassing – Use the ZIO as an “always on” effect in MUTE mode, or like a traditional
stompbox in “BYPASS” mode
Tuner/Line Out – ZIO features a tuner/line output that serves as an auxiliary output.
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Connecting the Pedal
Power
To power the unit, connect a 9-18V DC negative-tipped power supply to the jack labeled DC 9V on
the back panel.
Warning: Using an unregulated supply could damage the unit. Please be very cautious when using
3rd-party power supplies and refer to the power supply requirements in the Specifications section of
this guide.
Guitar/Audio Connections
Using standard ¼” mono (TS) cables, connect your guitar, bass, or other instrument to the INPUT 1
jack and your amp (or the next audio device in the signal chain) to the OUTPUT 1 jack. If you have a
second amp, connect it to OUTPUT 2.
When the power and audio connections have been made, ZIO is ready for use.
Input Side Connections
INPUT
INPUT is the primary input for guitar, bass, or other instruments. It can also accept line-level inputs
and will work in your amp’s effect loop. Connect it to your instrument or other audio source using a
mono (TS) 1/4” cable.
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Output Side Connections
MAIN OUTPUT
This is the primary audio output. Connect it to your amplifier, recording interface, or the next device
in your effects signal chain using a mono (TS) ¼” cable.
TUNER / LINE OUT
OUTPUT 2 can act either as an auxiliary audio output or an output for connecting to your tuner.
• TUNER / LINE OUT Output as an Audio Output: The tip contact on OUTPUT 2 acts as the secondary
audio output. It carries an audio signal when the ZIO is configured with a signal routing that uses
stereo outputs. Connect it to your amplifier, recording interface, or the next device in your
effects signal chain using a mono (TS) ¼” cable.
Power Connections
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DC 9V (Power)
Connect the ZIO to a 9-18 Volt DC power supply. The power supply must be regulated at 9 to 18
Volts DC (direct current), able to source at least 20 mA (milliamps) of current, and the plug should
have a tip-negative, barrel-positive polarity.
Higher Voltage
The ZIO can be powered at higher voltages up to 18V DC for extra headroom. Be sure that when
using a higher voltage supply such as 12V or 18V that the power supply is still DC (direct current) and
center-negative.
* * *
Preamp Modes
The ZIO features four discrete circuits to help further sculpt your overall tone. Each circuit has been
meticulously crafted for the best performance, feel, and response. JFET, LOW-CUT, and STUDIO
modes were all designed to have very low distortion. E-PLEX introduces a bit more grit at higher
output levels. Use the CIRCUIT selector knob to audition the circuit you’d like to use.
Each preamp mode can be combined with the TONE 3-way toggle selector for more meticulous tone
sculpting. Each of the modes will interact differently with the TONE switch, and you may prefer a
different combination depending on the voice you select. For example, the brightest possible
combination with the most treble response and clarity on the ZIO is the STUDIO preamp with the
TONE switch set to “BRIGHT”. The darkest possible combination with the most top-end roll-off is the
E-PLEX preamp with the TONE switch set to “DARK”.
Below is a description of each circuit along with a diagram of the circuit’s frequency response. It is
important to note that while the frequency response graphs are a good gauge for the EQ voicing of
each circuit, they do not tell the whole story of each preamp; they cannot capture the feel and
response of each circuit, nor can they convey individual characteristics such as the slight overdrive of
the E-PLEX mode.
JFET: This mode provides a very low distortion buffer or boost tone that is similar in character and
behavior to a clean tube amp input. Using high quality JFET Input Burr Brown OP Amps, JFET mode is
transparent, but is also designed not to add harshness and excessive brightness. JFET mode can also be
very helpful in a studio or home recording environment, not only to drive long cable runs or use as a
booster, but also to give a more natural sound to the DI or line inputs found on many pieces of studio
equipment. It can also be used as a buffered splitter (via the second output) in order to capture a direct
sound for later re-amping (for example, if you would like to record a live performance and then "clean it
up" in the studio for an official release). Due to its design, JFET mode can also interface with lower
impedance line inputs without excessive loss of bass content.
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LOW-CUT: The LOW-CUT mode is designed to remove excessive low frequency rumble and buildup that
makes it more difficult to get guitars (and sometimes basses!) to sit well in a mix. Unlike the STUDIO
mode, BASS CUT does not have an impact on the low midrange or presence frequencies, and, instead,
reduces the "low lows" to improve headroom and provide a tighter sound. This is especially useful on
guitar neck pickups, some basses, synths, and any other sound that may be too "boomy" and
overpowering in a live or studio mix. If you also have another pedal in your signal chain that has a
problematic low frequency loss when activated, BASS CUT mode can be used as an always on buffer to
reduce that bass beforehand. This way you can have a more even and predictable bass response overall
and compensate accordingly using your amp's tone stack or an "always on" EQ pedal.
STUDIO: The STUDIO mode is based on a pair of popular studio mixing tricks used on guitar and bass. It
combines an EQ curve based on the famous "Pultec Trick" (used on records since the 1950s and still
today) in combination with other tried and true methods to improve clarity. This mode provides a low
mid cut to remove "mud" frequencies, a gentle presence boost in the upper midrange, and a natural-
sounding high pass filter to reduce low frequency rumble. With this mode, you can achieve a more
"polished" sound that is intended to fit guitars and basses more clearly in a mix without excessive mud
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and bass frequency overlap. Without all that extra bass and mud, you also will gain more volume in the
most useful frequencies. This mode works very well after fuzz and overdrive pedals for tone shaping as
well!
E-PLEX: A recreation of the feel, character, and frequency response of a classic early 1970s tape echo
unit, the E-PLEX mode offers a vintage-style FET buffer/boost tone that is warm, clear, and a little bit
dirty. Many players used to turn off the echo on these old units and simply use the dry preamp for its
tone and feel as an always-on effect. In the original units, the output impedance was quite high, and this
led to a high frequency roll off with long cable runs. This was difficult to control, but also part of the
unit's top end character.
The ZIO can internally recreate the sound of a short cable run after the echo unit (as if it were sitting
near or on top of the amplifier) and a variable length of cable in front of the unit, using the TONE switch.
The combined effect gives a focus in the midrange without too much brightness or boomy bass.
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Where Do I Put the ZIO?
Despite being dubbed a “Front End”, the ZIO is a flexible pedal that can be strategically placed
anywhere in your signal path depending on how you intend to use it. There are no hard-set “rules”
for where to put your ZIO, but we’ve included a few signal path suggestions below.
Front of the Pedalboard
The ZIO is a great candidate to be the first pedal in your signal path. This is the most common place
to put the ZIO in your chain. It can be used to “drive” the rest of the signal path and sculpt the tone
& feel signal heading to the rest of your pedals and ultimately to the output destination (amp,
simulator, interface, mixing board, etc.). Its true bypass architecture means it will not interfere with
any picky fuzz pedals placed after it and can actually help to improve their performance.
After Drive/Gain Section
When used as a clean boost, ZIO can be placed after your dirt (distortion, overdrive, fuzz) section to
shape the overall tone and output level of these pedals, making it an excellent final gain stage.
Running overdrive pedals before the ZIO allows the ZIO to further shape the tone of these pedals.
Using the CIRCUIT and OUTPUT control, you can determine the overall shape, voice, and output level
of your signal heading outbound, similar to the preamp section of an amplifier.
End of the Pedalboard
When used like a buffer or signal restorative device, the ZIO is best placed at the end of the signal
path after the last pedal, right before the amplifier or final signal destination. For best results, do an
A/B comparison between your tone directly into your amplifier vs. into your pedalboard with the ZIO
engaged. Tweak the settings on your ZIO until the two tones match. We recommend using the JFET
circuit as a starting point since this is the most uncolored circuit, but any of the four circuits will have
its own unique feel and character.
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Controls
OUTPUT Knob
Think of this knob as a master volume control. Rotate this knob to boost your signal +20 dB or cut
your signal down to -∞ dB (zero volume). In addition to a powerful clean boost, the OUTPUT knob
can also be used to turn the ZIO into an “underdrive” when set to a gain level lower than the bypass
signal. Unity gain, or 0dB, is set to be around the 9:00 point of the OUTPUT knob.
CIRCUIT Selector Knob
The CIRCUIT Selector Knob selects between the four discrete circuits the ZIO offers: JFET, LOW-CUT,
STUDIO and E-PLEX. Each circuit has been carefully crafted to maximize performance and will react
differently in your setup. You may find yourself choosing different circuits for different applications
of the ZIO. For a more detailed description of each circuit, visit the Preamp Modes section of this
User Guide.
TONE toggle switch
The TONE toggle switch is a 3-way toggle that mimics short, medium, or long cable runs.
• BRIGHT simulates a low-impedance short cable run, preserving (and in many cases,
restoring) top end lost by long cables or large amounts of pedals.
• MED simulates a medium cable run and is the most “transparent” option, meaning it has the
least overall effect on the tone of your signal.
• DARK simulates a higher-impedance, long cable run with top-end roll off from the
capacitance. Use this mode to simulate a stadium-sized cable run or a coily cable. Some
players would intentionally use cables like this to shave off some of the naturally harsh-
sounding highs from their rigs.
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Each of these toggle switch positions can be combined with the CIRCUIT Selector Knob for the utmost
tonal variety.
SWITCH Toggle Switch
The SWITCH Toggle Switch is a 2-way toggle switch that sets the footswitch action. BYPASS causes
the footswitch to act as a normal engage/bypass footswitch. MUTE will mute the outgoing signal
from the ZIO when the ZIO is bypassed. In MUTE mode, the secondary “TUNER/LINE” output will
remain unaffected so that you can use your tuner while the signal is muted.
ON/OFF Footswitch
Click the footswitch to engage or bypass the pedal. In BYPASS mode, the footswitch acts as a normal
engage/bypass footswitch, and you will still hear the bypassed signal when the ZIO is off. In MUTE
mode, switching the Zio OFF will mute the MAIN OUTPUT, killing the outgoing signal entirely.
* * *
Specifications
Dimensions
• Length: 10.5 cm (4.1 inches)
• Width: 6.00 cm (2.36 inches)
• Height (not including knobs and footswitches): 4 cm (1.57 inches)
• Height (including knobs and footswitches): 5.65 cm (2.22 inches)
Weight
• 280 grams (0.625 pounds)
Power
• 20mA @ 9-18V DC
• Center negative, Barrel positive plug, 2.1 mm inner diameter, 5.5 mm outer diameter
Audio Performance
• Input Impedance: 1 Mega Ohm (1 MΩ)
• Output Impedance: 150 Ohm (150 Ω)
• True Bypass
Troubleshooting
Noise/Hum
Power source: Ensure that the proper power supply is being used.
Near noise source: Move pedal away from power supplies and other equipment.
Other equipment: Remove other effects from signal chain; see if noise persists.
Bad cables: Swap out audio cables.
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