Homebrew, open source, repurposed, hacked, software defined, open hardware

Wednesday, 25 June 2014

A PCM290x based USB sound card for radio amateur and other uses


design files are on github for the board, which will accommodate the PCM2902, PCM2904, PCM2906 versions (well, the PCM290x USB sound card IC family generally).


I get the boards made by hackvana, who can be found on Freenode in #hackvana.

Open hardware for the win!


The June 2014 edition of Amateur Radio magazine published a design for a USB sound card based on the PCM290x family of CODECs.

The depicted prototype used the PCM2904:

The board has optional connectors for the 3 switches supported by the CODEC, an SPDIF header for the codec models that support it, as well as space for 2 optional input and 2 optional output level adjustment potentiometers (Jumpered with 4 small wire links in the photo).

The board is 50mm x 50mm and has been designed for easy mounting in existing commercial rigs or homebrew rigs, or as a standalone unit. Input and output 3.5mm stereo sockets are supported to make connections simpler, as well as simple headers for those not using 3.5mm audio leads, and a Type B USB socket mounts directly to the board.

The option of an external regulated power supply for the ADC/DAC section of the CODEC is also supported.

Soldering was quick and easy, in fact three boards were done at once, using my hotplate liftoff jig technique.

A quick test after construction was successful with a G5RV equipped FT-817:


SDR homebrewers need to be aware of the one sample audio packet misalignment issue in some of the PCM290x revisions, and must either

1) choose unaffected revisions by studying the errata, or
2) empirically determine if the codec used does it, or
3) adjust their software to avoid phasing errors if using an affected codec

High quality hackvana made boards are now available at Aztronics

Here's the artwork, but homebrewers may struggle with the vias.


  1. Hi There,

    Hopefully this is not a duplicate post (not sure what happened with my previous attempt - site did something odd).

    Anyway, first heard about your great project in Amateur Radio and would be really keen to grab one of your PCBs. However, looking on Aztronics I've had no luck finding them. Any chance you could provide a direct link?


  2. It's well hidden, it seems, in the generic kits section of their website.


    Failing that, feel free to email them or call them, they have them in stock.

    Have fun!!


  3. Hi Erich,

    Great post. Have you made your PCB layout files available anywhere? I'm starting a PCM290x project and would love to use these as a starting point.