Building A ‘high-end’ USB Audio DAC

August 27, 2013 by Mathieu Stephan 63 Comments

As [Jan-Erik] had already built a simple USB connected Digital-to-Analog Converter (DAC), he decided to make the high-end version of it.

The prototype you see in the picture above is based on:

the PCM2707C from Texas Instruments which takes care of the USB communication and outputs I2S audio data
the PCM1794A, a 132dB SNR 24-bit 192kHz DAC which receives I2S protocol
the OPA4134, a high performance audio operational amplifier

The on-board +3.3V and -5V voltages are generated by inductor-less power supplies. As [Jan-Erik] mentions in his write-up, the ‘high-end’ was put between single quotes because the PCB is single sided and uses through hole passive components. The board was designed using Kicad, etched by himself and put in a machined enclosure. All the production files can be downloaded from his website so you may produce it within a day.

Exposing PCBs With A Home Made Laser Printer

August 9, 2012 by Brian Benchoff 50 Comments

Making your own printed circuit boards – as useful as it is – is a pain. Using the very popular toner transfer method requires a dozen steps that have to go perfectly the first time, and milling boards on a CNC machine creates a lot of mess. The most industrious hackers are able to bodge up a direct-to-board printer from an old inkjet printer, but these builds are usually a little kludgy. [Tixiv]’s LaserExposer board printer is one of the first builds we’ve seen that does away with all the negatives of the other techniques of PCB manufacturing and turns making your own boards into a very, very simple process.

The LaserExposer uses photosensitive copper board, like many of the other PCB printers we’ve seen. Instead of printing out the board artwork to a transparency or mask, [Tixiv] used a 1 Watt 445nm blue laser with a hexagonal mirror to directly expose the artwork onto the board, line by line.

The entire device is built around an old flatbed scanner that slowly crawls over the PCB, exposing the traces of copper to be etched away. This required reverse engineering the mirror motor control board from an 90s-era laser printer and building a circuit to precisely control the timing of the laser. [Tixiv] eventually got everything working and after etching had some of the most professional looking home-brew boards we’ve ever seen.

[Tixiv] put up a demo video of his build (after the break, German audio, YouTube has captions…). Anyone have an old flatbed scanner lying around?

Continue reading “Exposing PCBs With A Home Made Laser Printer” →

BatchPCB Pays You

March 1, 2010 by Devlin Thyne 80 Comments

SparkFun’s BatchPCB has been a well-known service to get your PCBs fabbed, and now it is sporting a new feature. It has just come out of its downtime chrysalis with the ability to pay you for making your designs. If you have designed a PCB and want people to pay you to use it, BatchPCB will now do that for you. [Patrick] says “We want engineers to benefit from the low-cost production for prototypes and have the ability to sell their work, conveniently.” There are a few caveats. First of all, each seller must be a resident of the United States and send BatchPCB a W-9. Secondly, PCBs are only warranted against manufacturing defects, so buyers should make sure the PCB they are buying is a working design. Finally, the sellers must only be selling designs of their own or with proper permission. We are big fans of free, open-source designs, but we can see how this would help an engineer recover some of their costs to develop a board and might lead to some interesting brokering of designs. What do you think of this new service?