PCM 2704

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nvd

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Joined 2009
#1
So here is another question from a newbie in this forum about PCM2704.

I got one of the USB DAC boards from Ebay. But I do not find it clear to listen to. The sound seems muddy. I am comparing the sound quality to Creative X-Fi which I have installed in PC.

Is PCM2704 really a good DAC? Is the sound quality dependent upon the quality of on-board components? How much?
Since it is sourced from China, capacitors may be of lower grade.

I got free samples of PCM2704 from TI as well but have not given them a try.
Are there fake PCM2704s floating around that might be in the board that I bought?
 
#2
I'm designing a cheap USB DAC based on the PCM2706. If you can wait a month, I'll let you know how it sounds with known quality components. One thing that some designs do and some don't is to separate the analogue/output grounds from the USB grounds with a resistor and cap, that may make a difference.

Also keep in mind the PCM270* series only support 16-bit/48KHz max, where your X-Fi probably supports 24-bit/192KHz.
 
#3
I think, the crystal can also make a huge difference. Jitter can cause the sound to deviate from the ideal one. X-Fi is 24-bit sound card but I am playing 16-bit audio.

I have seen other projects where PCM2706 is just used for I2S stream source and another higher quality DAC is used as the stream sink.

Let's see how it turns out on your side.
 
#4
I designed my DAC with that in mind. It has analogue out for use now, but an I2S header for connection to a TDA1541A DAC I'll be making later.

Also, while still using a crystal as opposed to an external clock, the one I've chosen has a stability of 35ppm, better than some others.
 
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