Basic DAC Question (PCM2707)

[wiredmonkey]

Hi All,

I'm completely new to the world of DAC's but am looking at building one to connect to my gainclone from my laptop. I have recently received samples of the PCM2707 and thought I would simply connect it to the USB and connect the analog output pins to a nice opamp such as a opa2134. However, every search I do everyone connects this chip to another DAC using the I2S interface. Is there a reason for this and what are the problems I will face if I go down the path of designing a DAC on my simple idea?

Thanks!

[error401]

Originally posted by wiredmonkey
Hi All,

I'm completely new to the world of DAC's but am looking at building one to connect to my gainclone from my laptop. I have recently received samples of the PCM2707 and thought I would simply connect it to the USB and connect the analog output pins to a nice opamp such as a opa2134. However, every search I do everyone connects this chip to another DAC using the I2S interface. Is there a reason for this and what are the problems I will face if I go down the path of designing a DAC on my simple idea?

Thanks!

The performance of PCM2707 as a DAC isn't all that great, especially compared to its brother the PCM2702, which is the one everyone uses as a standalone DAC. Since the PCM2702 is so much better, the PCM2706/7 are primarily used as a USB->I2S (or SPDIF) interface.

There's nothing inherently wrong with the PCM2707's DAC, it works fine and it's just as easy to use as the PCM2702. Just consider:

PCM2707 THD+N into 10K - 0.012%
PCM2702 THD+N into 10K - 0.002%

PCM2707 SNR-A - 98dB
PCM2702 SNR-A - 105dB

PCM2707 channel separation - 70dB
PCM2702 channel separation - 103dB

[wiredmonkey]

OH! That explains it I'll go get some pcm2702's now! I guess whilst I've started this thread would anyone know where I could get a TQFP 32 to DIP adapter in Australia?

[error401]

Originally posted by wiredmonkey
OH! That explains it I'll go get some pcm2702's now! I guess whilst I've started this thread would anyone know where I could get a TQFP 32 to DIP adapter in Australia?

Can't help you with that query, but PCM2702 if you're going to use it is SSOP28.

You might also be interested in the AlienDAC, it's based on PCM2702 and kits and PCBs are available for purchase here (no affiliation).

[wiredmonkey]

Great link, I think I'll pick up one of those kits. Thanks a lot!