john12ax7

D/A converter schematics
« on: January 20, 2018, 07:23:25 PM »
I've looked around but haven't found much,  looking for some audio converter schematics to study.

Looking to build some D/As. I would think something like an AES receiver chip with clock recovery, that feeds a dac and then an analog I/V stage.  How does the receiver attenuate the jitter? Do you still need a clean PLL and crystal in this case? I would think you still need a clean reference.

Any schematics or relevant part numbers would be appreciated,  especially for the receiver and clocking part.


ruairioflaherty

Re: D/A converter schematics
« Reply #1 on: January 20, 2018, 11:01:54 PM »
I've looked around but haven't found much,  looking for some audio converter schematics to study.

Looking to build some D/As. I would think something like an AES receiver chip with clock recovery, that feeds a dac and then an analog I/V stage.  How does the receiver attenuate the jitter? Do you still need a clean PLL and crystal in this case? I would think you still need a clean reference.

Any schematics or relevant part numbers would be appreciated,  especially for the receiver and clocking part.

Hey John,

When I was trying to wrap my head around converter topologies I found looking at manufacturer Evaluation boards to be really helpful.  They are usually fairly lean designs but high performance.

Many of the state of the art converters are using a local oscillator and reclocking the input, the Benchmark DAC 2 and 3 and good examples.

I like this white paper from Ian Dennis at Prism Sound

http://www.prismsound.com/test_measure/support_subs/resource.php?rid=173

And some slides from a presentation he gave that are related

http://www.aes-media.org/sections/uk/Conf2011/Presentation_PDFs/02%20-%20Ian%20Dennis%20-%20Performance%20challenges%20in%20audio%20converter%20design.pdf


john12ax7

Re: D/A converter schematics
« Reply #2 on: January 21, 2018, 02:20:27 AM »
Thanks, I will take a look at those.


ruairioflaherty

Re: D/A converter schematics
« Reply #4 on: January 31, 2018, 10:50:52 PM »
Another resource for DAC development is NWAVguy's blog

Here's a relevant page but you can search through the blog history for more posts. 

http://nwavguy.blogspot.com/2012/04/odac-released.html

For those in the know there will be nothing earth shattering here but it's fun reading to gain an insight into some of the design challenges in building a DAC

Rochey

Re: D/A converter schematics
« Reply #5 on: May 15, 2018, 01:49:17 PM »
Might I suggest you start with something simple and get some quick success, before aiming for the moon?

I'm incredibly biased (this was my part when I was at TI - I defined it to be a simple, easy to design-in, high performance DAC), but just try doing a schematic and layout for a DIR9001 + PCM5102A setup.

It'll give you 112dB SNR, and support up to 96kHz, but the design is very forgiving and easy to make.
I'd also hook up all the IO pins to an Arduino so that you can reconfigure the part easily.

Cheers

Rochey

Expat Audio Home: http://www.expataudio.com