Newbie usb dac and headphone amp

[darragh]

Hi,

I am a total newbie when it comes to diy audio. I have absolutely no experience with this stuff.
I have a Total Bithead at the moment which I really like and I would like to learn a bit more about building a USB DAC, is there any good resources for total newbies to have a look?

I really would like to build a USB DAC and headphone amp around the PCM1704 chips eventually and I have the assistance of a very good electronic engineer and access to a good electronics lab. Is there any schematics for a USB DAC based around the pcm1704 chips?

Thanks
Darragh

 

[rfbrw]

Are you certain you mean the PCM1704 not the PCM1794. The PCM1704 is a mono device and brings increased complexity. The PCM1794, OTOH, will connect directly to the usual USB receivers.

 

[darragh]

I understand the PCM1704 is a mono device and that will bring more complexity, as they will have to be interfaced at some point to the USB bus but I would like to keep the channels separate until after the analog amplification stage.

 

[rfbrw]

The USB schematics I've seen all more or less follow the datasheet/application note so pick one. In your shoes I'd buy a ready made USB to audio data module and put my effort into the dac side of things.
As far as the PCM1704 schematics go, I've yet to see one for just the PCM1704 alone. It is usually preceded by something like the DF1704. For a DF1704/PCM1704 schematic try the DEM DAI1704 evaluation board schematic, it should be on the TI site. You could also search the forum for David Broadhurst's design or the web for the Hagdac for inspiration.
You should also know that the PCM1794 will also operate in mono and interface directly with a USB receiver as will the the AD1955 but it requires a micro-controller.