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Old 3rd October 2011, 09:05 PM   #21
EUVL is offline EUVL  Europe
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Eric,

It was just a remark, not a criticism by all means.
I guess we take different approaches in certain peripheries like power supply.

When I am finished with mine, maybe we have a better basis for exchanging notes.




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Patrick
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Old 4th October 2011, 07:04 AM   #22
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Quote:
Originally Posted by EUVL View Post
Eric,

It was just a remark, not a criticism by all means.
I guess we take different approaches in certain peripheries like power supply.

When I am finished with mine, maybe we have a better basis for exchanging notes.




Best regards,
Patrick
Hi Patrick,
I didn't feel any criticism at all. I laugh when I read your post; I'm glad to see someone else interesting with this part
It will be very interesting to made evaluation with two different approaches.

Best regards,

Eric
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Old 30th November 2011, 09:50 AM   #23
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Tried this DAC chip yesterday, and it's very easy to build. Noticed that it's quite sensitive to good power supply, running from a standard regulator it sounded very thin.

With decent power supply it sounds OK, but also quite "edgy", not very pleasant to listen to, but with plenty of detail, and some sound stage. For the money (one can build a DAC for like 10 euro's) it's a nice IC.
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Old 30th November 2011, 01:48 PM   #24
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Hi Hobbit13,
Quote:
Originally Posted by Hobbit13 View Post
Tried this DAC chip yesterday...
Thanks for your feedback.

Quote:
Originally Posted by Hobbit13 View Post
...With decent power supply it sounds OK, but also quite "edgy", not very pleasant to listen to...
To avoid unpleasant effect, increase capacitor decoupling on negative charge pump pin 5 and take care on part quality. Ti's recommendations (2.2F) are a bit short.
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Old 30th November 2011, 03:08 PM   #25
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Do you know when diminishing returns begin with increasing that capacitor?

I just wish there was a little bit more insight into the pcm5122 and what additional features that contains.
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Old 30th November 2011, 03:15 PM   #26
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Default Why the interest in this chip?

Hi Eric,

Would you explain why you find this chip to be particulaly interesting?

It features relatively poor THD figures for a sigma-delta converter. The integrated digital filter does not feature a true apodizing mode, it simply has a minimum-phase mode which is only part of a true apodizing filter. In addition, the filter has quite poor stop-band rejection. Not to mention the potential audible consequences of using a charge pump (which is simply a cost saving measure) to generate the negative supply needed to produce a ground centered output rather than require an extenal negative supply be provided.
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Old 30th November 2011, 04:09 PM   #27
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Well Ken I think you're missing the point.

This is TIs attempt at producing an inexpensive DAC that requires an extremely small number of supporting components and only requires a single 3.3v PSU from which to work. This will fit it into a great number of systems without requiring any additional supporting hardware, on that note the built in PLL also removes the need for the master clock, once again aiding in ease of use and simplifying design.

If you're expecting class leading THD/SNR and digital filtering then you are not appreciating what this device is supposed to be used for, it isn't intended as a top line audiophile product. No doubt those will come later, after-all the PCM1792/4 flagship products are ~10 years old and will probably be replaced at some point.
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Old 30th November 2011, 05:15 PM   #28
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ESS Tech also introduced the ES9022/9023 for the same intended application.
And there are quite a few people here who have done extensive experimentation with that chip.

I can tell you from my own experience that what Eric said has a lot of truth to it.
And you should not underestimate how good these modern "low end" chip sound.

I have more than a few neutral feedbacks that ES9022 when done properly outplays the ES9018 datsheet implementation.


Patrick
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Old 30th November 2011, 06:22 PM   #29
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Quote:
Originally Posted by Extreme_Boky View Post
I think similar technique was used by YM 3623B receiver; I liked that chip a lot. Yamaha chip was locking on an external clock and then disconnecting that input while using an internal PLL controlled oscillator to provide clock signals internally. This was also an attempt to isolate cheap quartz xtal oscillator from receiver internal processing. It seemed that it worked quite well - this receiver was regarded as one of the better sounding chips...

Boky
Hi Boky, there has not been a worse receiver than YM3623B. Good old CS8412 was way better. You also needed to stop the external clock when the receiver locked which was not provided in the chip so the external clock interfered (AFAIK as this was many years ago). Elektor published oscilloscope pics of what happened and introduced the "diode-mod" which was very effective.

From what I can tell from the data sheet ES9022/3 are ahead of this TI chip. But as always the proof of the pudding is in the eating.....


Quote:
Originally Posted by fitzfish View Post
There is one significant difference with this DAC that deserves some consideration as compared to the 9022/23 - the master clock implementation.

The 9022/23 requires an external low noise master clock whether working synchronously or asynchronously.

From the datasheet the 150x chips can generate the master clock from the incoming data stream using a internal PLL and no external master clock input or oscillator. In doing so it supports any sample rate frequency directly with only the bit clock, L/R, and data signals. A good question is how well it does this? It would be very interesting to see how good this internal PLL and oscillator are by building one and doing some testing.

If this PLL mode works well this may be an interesting way to shave off the expense of the external oscillator and its low noise power supply (as compared to the 9022/23 at least).

If it does not work as well in PLL mode as the 9022/23, an external oscillator can be supplied to the 1502 but it must be selected to work on either 44.1KHz multiples or 48KHz multiples. It won't do both with one clock frequency.

The best performance looks to be achieved with an external low noise oscillator and working synchronously from an SD player or a fixed rate transport, etc. This is probably where the comparison between the 9022/23 and the 1502 should be made because it is the closest thing to an apples-to-apples comparison.

Food for thought...

I am looking forward to someone trying it out.
Dave
Good info Dave. I think I will continue my plans with ES9023. I have a gut feeling that ES9023 is also better with jitter figures in real life but I don't have any equipment for measuring that. I think you measured it to have 3 ps jitter ?!
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Last edited by jean-paul; 30th November 2011 at 06:30 PM.
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Old 1st December 2011, 03:26 AM   #30
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Thanks Jean-Paul.

I did measure very low jitter levels with the 9023 using the jtest method. If you look at the fourth graph here you will see it. It is important to point out that this test is really an indication of the data correlated jitter performance of the whole DAC as a system - the reciever, layout, power supplies, etc., not just that of the 9023 itself. Still extremely good that a 2 dollar DAC chip with a 4 dollar reciever chip can perform at this level. The random jitter is also very low as seen by the noise floor in the graphs. It took quite a bit of power supply work to get the other sources quiet enough to see this.

Best of all, it also sounds great

Dave
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