Source Audio ZIO - User Manual

SA272 ZIO Analog Bass Preamp + D.I. User Guide
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USER’S GUIDE
Welcome
Thank you for purchasing the ZIO Bass! ZIO Bass is an all-analog bass-tuned preamp & boost with audio,
direct (XLR) and headphone outputs for ultimate flexibility when optimizing your bass rig. ZIO Bass
utilizes the same high-quality, low-noise Burr Brown OP-amps as the original guitar-focused ZIO,
expressly selected and tuned for maximum performance on bass. We reunited with our good friend and
collaborator, Christopher Venter of SHOE Pedals, who worked on the original ZIO, Atlas Compressor, and
other previous Source Audio effects to create this homage to the bass-playing tonal connoisseur.
ZIO Bass incorporates a fully featured EQ section, allowing the player to perfectly shape their bass’s low
and high-end response. The BASS and FOCUS knobs are two highly interactive controls that define the
tone of your note fundamentals: a 100Hz-boosting shelving and a sweeping high-pass filter create a
custom peak response when combined. The TREBLE control is an active cut/boost shelf set to 1kHz
focused on dampening or accentuating harmonic overtones. ZIO Bass also features two optional circuits:
the GRIT and SCOOP toggle switches. GRIT introduces a warm, organic, transformer-style distortion
caused by the effect “hysteresis”, the level of which can be set by the GAIN trim pot. SCOOP removes
some lower midrange frequencies that have the potential to overpower the signal.
The word "ZIO" is an acronym for Impedance (Z), Input (I), and Output (O). The goal in creating this
pedal remains the same: we wanted to “make everything sound better.” We hope you’ll agree.
—The Source Audio Team

Summary

Welcome

Feature Overview

Up to +16 dB of Output Boost

Boost your output level heading into your amplifier, interface, FOH, or other output destination.

High Headroom Design

Utilizes two +/- 12 V internal supply rails for maximum headroom and dynamic range.

Buffered Bypass

Features discrete, high-quality buffers for bypassing the signal path architecture.

Compact Design

Anodized bent aluminum housing, slim profile, and small footprint for rigors of the road.

Discrete Analog Circuitry

Utilizes high-quality Burr Brown OP-amps, tuned for maximum performance.

Analog Distortion Section

Recreate transformer-style vintage amp distortion with GRIT toggle switch.

Low-End Sculpting

Use BASS and FOCUS controls for detailed low-end contouring.

Discrete Headphone Output

Optional headphone output for silent home or on-the-go playing.

Connecting the Pedal

Power Connection

Connect a 9V DC negative-tipped power supply to the DC 9V jack on the back panel.

Input Jack

Primary input for bass/instruments; accepts line-level inputs or amp effects loop.

Output Side Connections

Main OUTPUT

Primary audio output for amplifier, recording interface, or next device in effects chain.

Headphone Output

High dynamic range, low-noise amplifier for driving low impedance studio headphones.

DIRECT OUT

Balanced XLR Output for easy connectivity to audio interface, mixing console, PA.

Ground Lift Switch

Lifts internal ground for DIRECT OUT to reduce hum or buzzing.

GAIN Trim Pot

Adjusts distortion level for GRIT toggle switch when set ON.

Power Connections

DC 9 V (Power) Requirements

Must be regulated, 9V DC, tip-negative, source at least 200mA.

High Voltage = High Headroom

Internal 24V operation provides higher clean headroom than traditional stomp-boxes.

Controls

OUTPUT Knob

Master volume control; boosts +16dB or cuts -6dB; can create 'underdrive'.

BASS Knob

Low-end boost (shelving filter at 100Hz); boosts up to +11dB, cannot cut low end.

TREBLE Knob

TREBLE Control Function

Shelving filter at 1kHz; boosts 1kHz+ by +14dB or cuts by -6dB.

GRIT Toggle Switch

GRIT Function

2-way ON/OFF toggle for vintage bass amp transformer-like distortion.

Adjusting GRIT Gain

Use Phillips screwdriver to adjust external trim pot for desired distortion level.

FOCUS Knob

FOCUS Control Function

High-pass filter control; moves bass-cutting filter right into higher frequencies.

SCOOP Toggle Switch

SCOOP Function

Mid-scoop circuit emulates Pultec EQ trick; low-mid cut, subtle bass boost, high-freq shift.

Specifications

Dimensions

Details physical measurements: Length, Width, Height, Weight.

Power Requirements

Specifies current draw (140mA/200mA) at 9VDC.

Troubleshooting

Noise;Hum Issues

Addresses power source, near noise, other equipment, bad cables, ground loops.

Dead Unit; No LEDs

Troubleshoots power supply issues causing unit to appear dead.

Frequently Asked Questions

Instrument Compatibility

Discusses compatibility with basses, guitars, synths, and other electric instruments.

Phantom Power Protection

Confirms Zener diodes protect against phantom power.

Effects Loop Usage

Guidance on using the ZIO Bass in an amp's effects loop.

Rubber Feet

Warranty

Limited Transferrable Warranty

Details warranty coverage, duration, and transferability for USA purchases.

Warranty Information

Service and Repairs

Explains how to obtain service or repair, including return authorization.

Disclaimer and Limitation

Outlines warranty limitations, exclusions, and legal rights.

Version History

Overview

1. Function Description
2. Important Technical Specifications
3. Usage Features
4. Maintenance Features

The ZIO Analog Bass Preamp + D.I. is an all-analog, bass-tuned preamp and boost pedal designed to optimize a bass rig with versatile audio, direct (XLR), and headphone outputs. It leverages high-quality, low-noise Burr Brown OP-amps, similar to its guitar-focused predecessor, and was developed in collaboration with Christopher Venter of SHOE Pedals. The name "ZIO" is an acronym for Impedance (Z), Input (I), and Output (O), reflecting its core purpose to enhance sound quality.

Function Description:

The ZIO Bass serves as a comprehensive tone-shaping tool for bass players. Its primary function is to provide a clean boost, an extensive EQ section, and an optional distortion circuit, all within an all-analog signal path.

• Preamp and Boost: The pedal offers up to +16dB of output boost, allowing users to drive their amplifier, audio interface, or FOH system effectively. The OUTPUT knob acts as a master volume, capable of boosting the signal by +16dB or cutting it by approximately -6dB, effectively turning the ZIO Bass into an "underdrive" when set below the bypass signal level.
• EQ Section:
  • BASS Knob: This control is a shelving filter centered at 100Hz, providing a low-end boost. It starts flat at fully counterclockwise and can boost bass frequencies by up to +11dB when fully clockwise. It is designed only for boosting, not cutting, low frequencies.
  • TREBLE Knob: This is also a shelving filter, situated at 1kHz. Its "flat" position is at noon. It can boost 1kHz and above by +14dB at maximum (fully clockwise) and cut 1kHz and above by -6dB at minimum (fully counterclockwise).
  • FOCUS Knob: This knob functions as a high-pass filter, designed for detailed low-end contouring in conjunction with the BASS knob. Rotating it clockwise moves the bass-cutting filter into higher frequencies, effectively cutting more low-end. When the BASS control is active, the FOCUS knob can create a peak in the bass response by pitting the movable HPF against the fixed 100Hz bass-boosting shelving filter.
• GRIT Toggle Switch: This 2-way ON/OFF toggle switch introduces a vintage bass amp transformer-like distortion. The amount of distortion is controlled by an adjustable trim pot on the pedal's OUTPUT side. The GRIT circuit is highly interactive with the input signal, and while it introduces distortion, it causes only a minor treble fall-off around 1100Hz.
• SCOOP Toggle Switch: This 2-way ON/OFF toggle switch activates a mid-scoop circuit, emulating the Pultec equalizing trick. It provides a gentle low-mid cut to reduce "muddy" frequencies, a subtle bass boost centered at 40Hz, and a dramatic shift in high frequencies starting at 750Hz and peaking around 6kHz. There is a mild interaction between GRIT and SCOOP, where GRIT can smooth out boosted treble frequencies and reduce the severity of treble boosting in the SCOOP circuit by over 1dB.
• Outputs:
  • Main OUTPUT: The primary audio output for connecting to an amplifier, recording interface, or other effects using an unbalanced mono (TS) ¼" cable.
  • Headphone Output: A 1/8" (3.5mm) TRS output featuring a high dynamic range, low-noise amplifier capable of driving low impedance studio headphones. This output is only active when in use.
  • DIRECT OUT (XLR): A balanced XLR output for direct connection to an audio interface, mixing console, or PA system. It includes phantom power protection.
• Ground Lift Switch: Located on the output side, this switch lifts the internal ground connection to the DIRECT OUT XLR jack to eliminate "hum" or loud buzzing when using the direct output. It does not affect the instrument or headphone outputs.

Important Technical Specifications:

• Power:
  • 9V DC, negative-tipped, barrel-positive polarity.
  • Regulated power supply required.
  • Current Draw: 140mA (without headphone output) / 200mA (with headphone output).
  • Internal Supply Rails: Two +/- 12V rails, boosting internal voltage up to 24V for maximum headroom and dynamic range.
  • Note: Do NOT use power supplies higher than 9V (e.g., 12V, 18V) to avoid damage and voiding the warranty.
• Audio Performance:
  • Input Impedance: 1 Mega Ohm (1 MΩ)
  • Main Output Impedance: 75 Ohm (75 Ω)
  • XLR Output Impedance: 75 Ohm (75 Ω)
  • Headphone Output Impedance: 42 Ohm (42 Ω)
  • Maximum Input Headroom: +/-10V
  • Bypass: Active Analog Buffered Bypass. All outputs remain active whether the effect is engaged or bypassed.
• Dimensions:
  • Length: 4.13 inches (105mm)
  • Width: 3.07 inches (78mm)
  • Height: 1.54 inches (39mm)
  • Weight: 0.45kg / 1lbs
• Input Compatibility: Can accept line-level inputs and works in amp effects loops, handling up to 8.76 dBu or 6.0 Volts peak-to-peak.

Usage Features:

• Versatile Connectivity: All three outputs (Main, Headphone, XLR Direct) can be used individually or simultaneously, both when the pedal is engaged and bypassed, offering ultimate flexibility for various setups (live, studio, practice).
• Compact Design: Housed in an anodized bent aluminum enclosure with a slim profile and small footprint, making it suitable for pedalboards and the rigors of touring.
• External GRIT Gain Trim Pot: The amount of distortion from the GRIT circuit can be fine-tuned using a small Phillips head screwdriver on the external trim pot located on the OUTPUT side. This allows users to customize the drive based on their instrument's signal strength, pickup height, amp headroom, and other pedals in the signal chain.
• Instrument Compatibility: While specialized for bass, the ZIO Bass can also be used with guitars, synthesizers, and other electric instruments due to its relatively high input headroom, accommodating both active and passive pickups.

Maintenance Features:

• Buffered Bypass: The discrete, high-quality buffers ensure signal integrity even when the effect is bypassed, maintaining a consistent signal path.
• Phantom Power Protection: The DIRECT OUT (XLR) is protected against phantom power, ensuring safe connection to mixing consoles and audio interfaces.
• Troubleshooting Guidelines: The manual provides clear steps for addressing common issues such as noise/hum (checking power source, proximity to noise, cables, ground loops, and using the ground lift switch) and the unit appearing dead (checking power supply).
• Warranty: Source Audio offers a two-year limited transferable warranty for units purchased from an authorized dealer in the USA, covering defects in materials and workmanship under normal use. Warranty registration is available online. Unauthorized service or modification will void the warranty.
• Waste Disposal: Users are advised to dispose of the device at an electronics recycling center rather than with household waste, promoting environmental responsibility.

Source Audio ZIO Specifications