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USB-I2S Module and Analog Board version 1.1

The USB-I2S Module and AB-1.1 give you open source USB audio in a modular design. It even comes in a nice enclosure. We encourage you to play with it, change the code and modify the hardware.

The kit is part of the Audio Widget open source project. It is a fork of the SDR Widget project. Homepages are found here:
There's a major thread at diyAudio. Please see the FAQ for a list of particularly interesting posts!

So, what does it do?

Nice! What does it cost?

A single boxed, assembled and tested kit costs USD 120 plus shipping. This option has OS-CONs mounted at 5 critical points of load (XOs and DAC). I only have assembled AB-1.1 kits in stock, not single modules. Besides, I really recommend buying a working starting point. Single modules may come with future batches.

Special offer for analog modders: Buy two kits and shipping is included! This option comes with the 10 OS-CONs loose and unassembled for you to play around with. Then you can use two AB-1.1s for proper A/B testing!

Please choose the right total sum in USD from the pull-down menu below. It will take you straight to PayPal. If you are interested in buying more kits, or if you wish to use a courier, please contact me at borge.strand@gmail.com. Disclaimer: "I take no responsibility for the safe arrival of goods in Russia. If you want delivery there and don't want to take the risk, please provide a shipping account number with FedEx, DHL, UPS or similar."

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Pictures and Schematics

Click the thumbnails below to get larger pictures. There are two schematics, one for the USB-I2S module and another for AB-1.1.


USB-I2S Module

The module uses the Atmel AVR32 AT32UC3A3256. It includes everything you need to go from USB on one side to I2S on the other side. The board has an LDO with the option of VBUS or local powering. In addition it has plenty of IO for functions that may become usefull in an audio DAC. There is support for:

Analog Board 1.1

AB-1.1 is the motherboard for the USB-I2S module. It includes all the analog functions for audio playback. It is designed to be a fully functional and good sounding board. But it has not been tweaked and optimized for the very best in analog Hi-End performance. The ES9023 output filter capacitors are not assembled. Some people think that sounds good, others believe the caps should be there. With AB-1.1 you can try out different options. Everybody is welcome to start out with this board and make an AB with their favourite power / DAC / IVC etc. AB-1.1 includes:


Q: Do I have to be a programmer to use the USB-I2S module and AB-1.1?

A: No, you don't. It plays music right out of the box. But you may have to install new firmware. That pretty much means following a quite doable procedure of driver installs, button pushes and DOS/shell commands.

Q: Do I have to be an analog hacker to use the USB-I2S module and AB-1.1?

A: No. But if you have a soldering iron you can tweak it. The kit is not a finished product. Although it works very well, it is designed as a starting point for DIYers.

Q: I am a programmer. Where do I start?

A: Visit the project links at the top of this page and join both SDR-Widget and Audio-Widget mailing lists. There is very little cross-posting. The SDR-Widget Wiki is a good starting point. It explais the git repository and other details.

Q: Which coding efforts are wanted?

A: We're always trying to improve on the MCU firmware. Our most pressing issue right now is Windows driver support. If you're familiar with Audio processing / USB / Windows drivers / Linux drivers, or related things, please join our efforts.

Q: I like analog tweaking. Where do I start?

A: It is very possible for you to design your very own Analog Board and fit the USB-I2S module on it. Such a board must include DAC, clocks and PSU. But if you don't want to make the whole thing from scratch, feel free to download the AB-1.1 schematics and see if there are areas where your knowledge can improve on things. Oh, and please feed your knowledge back to the group members.

Q: I'd like to reuse the PCB designs for a commercial project. What do I do?

A: Contact me at borge@qnktc.com. I have years of experience in commercial PCB design and manufacturing. We'll something out!

Q: The diyaudio thread is huge. Where do I look?

Capacitors posts 670, 756, 763, 854, 867
Linux player posts 758-759, 800
Layout, back panel posts 819, 825, 831
Test results post 819 currently evolving...
Jtest posts 761, 776, 781 currently evolving...
Feel free to suggest other highlights!!

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