The ζ1 Audio Widget asynchronous USB-I²S module
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ζ1 ("zeta one") is a circuit module that performs USB audio to Philips I²S translation, for use in devices such as digital-to-analog converters or digital audio transceivers.

Feature summary

  • High performance USB audio interface - USB input, I²S output.
  • Operates as a USB peripheral audio device.
  • Assembled, pre-flashed with firmware and tested.
  • Onboard Atmel AT32UC3A3256 32-bit microcontroller with 256KB flash memory.
  • User-upgradable firmware (via USB port).
  • Asynchronous transfer mode* for uncompromised low jitter performance.
  • Bit-perfect audio.
  • USB Audio Class 1 and 2 compliant.
  • UAC1 (USB 1.1 full speed): up to 24 bits; 44.1KHz and 48KHz sample rates.
  • UAC2 (USB 2.0 high speed): up to 32 bits; 44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz and 192KHz sample rates.
  • Mini-B USB connector.
  • Onboard tactile switches for UAC1/UAC2 toggle and for firmware upgrade mode.
  • Onboard LED indicators for asynchronous rate-feedback action.
  • External LED indicator for power and UAC mode.
  • Can be bus-powered or self-powered (5V DC).
  • All surface-mount components on high quality FR-4 circuit board with four copper layers.
  • Computer, smartphone and tablet host support: Linux, MacOSX, Windows, iOS and Android.
  • Available Win-Widget ASIO device driver software for UAC2 support on Windows.
  • Open-source design (firmware and driver source code, schematic diagram).
  • Based on Audio Widget, a branch of the SDR-Widget project, and developed by enthusiasts.
  • AMB implementation with community participation.
  • Currently used in the γ1.5 miniature high-resolution USB DAC + headphone amplifier and γ3 high resolution DAC.
  • Can be used to implement other high resolution USB audio solutions.
  • Small module size for easy integration into new designs.
* More specifically, "isochronous-asynchronous" mode.

How to use the ζ1 Audio Widget module

Since the ζ1 modules are supplied in assembled and tested form, for γ1.5, γ3 or other devices designed to use the ζ1, you simply plug the ζ1 module into matching connectors on the device. However, the ζ1 modules are supplied without the pin receptacle strips needed for plugging the module. You need to obtain those connector strips and solder them to the ζ1 module. See the Parts list section for details.

Detailed information about installing the Win-Widget software device driver for Windows platforms, switching between UAC1 and UAC2, flashing the firmware and other topics are found in the Instructions section.

If you are designing a new circuit around the ζ1, please read the Design integration section.

To obtain the ζ1 module, visit the AMB audio shop.

Where to get help

Be sure you read all the information at this site before mounting and using the ζ1 module.
  • If you're building an AMB project that uses the ζ1 module (such as γ1.5 or γ3), and you cannot find an answer to a question, or encounter a problem you cannot solve, the best place to get support is AMB DIY audio forum. Search the forums for an answer before asking a question. Your question may have already been asked and answered.
  • If the ζ1 module is being used on a non-AMB project, then please contact the designer or use an appropriate support channel for that project.
  • If you are a designer working to integrate the ζ1 into your project, please use the Audio Widget discussion forum.

A 3D rendering of a the ζ1 Audio Widget asynchronous USB-I²S module.

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