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Old 16th February 2021, 03:12 PM   #451
syn08 is offline syn08  Canada
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For STEREO it was clear from the very beginning. I was wondering about MONO, one DAC chip (8 analog output channels in parallel) for L, and another DAC chip (8 analog output channels in parallel) for R, all in PCM mode. Is this even possible?

Last edited by syn08; 16th February 2021 at 03:15 PM.
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Old 16th February 2021, 03:14 PM   #452
Markw4 is online now Markw4  United States
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For mono, set all L/R dac pairs to either the L or the R part of the selected digital input signal. The chip has dedicated DATA input pins for PCM. Pick one as the mono digital input.

The GPIO pins may be optionally assigned to act as extra SPDIF inputs.
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Old 16th February 2021, 03:14 PM   #453
altor is offline altor  Israel
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Sorry, I missed that you wants MONO.
For MONO - do not set bit2 in reg #15, then set all register #38-41 in one chip to zero (0x00) and to 0x11 in the second chip.
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Old 16th February 2021, 03:23 PM   #454
capslock is offline capslock  Europe
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Quote:
Originally Posted by syn08 View Post
Chris, you are correct, I have experimented with an AK5572 evaluation board and it is slightly worse than the AK5394, plus the annoying noise shaping that makes THD+N measurements over 10KHz almost meaningless.
You mean slightly worse in terms of THD?

Actually, having seen QA-Matts posts about the prototype QA 402 with PCM4220 driven by an analog oscillator, the PCM also seems to have stellar THD performance (HD2 at -128 dB for +6 dBV input), and unlike the AK5374A, it degrades more gracefully near full scale. What remains is a lowish noise corner:

Sneak Peek: The QA402 - #24 by matt - QuantAsylum Forum
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Old 16th February 2021, 04:09 PM   #455
syn08 is offline syn08  Canada
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Quote:
Originally Posted by altor View Post
Sorry, I missed that you wants MONO.
For MONO - do not set bit2 in reg #15, then set all register #38-41 in one chip to zero (0x00) and to 0x11 in the second chip.
Thanks, but this doesn't match with the datasheet. First, setting all registers to 0x00 means "map input1" and 0x11 means "map input2" on all DACs. But the datasheet says that "input1" and "input2" refer to the digital inputs (2...5 for PCM) so something is off here. I would expect to have a way to specify through a bitmap in the registers a) the digital input and b) the L/R channel in that input, which doesn't appear to be possible (unless I'm missing something), hence my confusion.
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Old 16th February 2021, 04:30 PM   #456
altor is offline altor  Israel
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Originally Posted by syn08 View Post
Thanks, but this doesn't match with the datasheet.

Why?

Quote:
First, setting all registers to 0x00 means "map input1" and 0x11 means "map input2" on all DACs.
Yes, exactly!

Quote:
But the datasheet says that "input1" and "input2" refer to the digital inputs (2...5 for PCM) so something is off here. I would expect to have a way to specify through a bitmap in the registers a) the digital input and b) the L/R channel in that input, which doesn't appear to be possible (unless I'm missing something), hence my confusion.
Not clear what you mean.

Considering PCM only:
Chip have 4 I2S data lines, 2 channels each, named as DATA2, DATA3, DATA4 and DATA5.
By default, DATA2 - CH1 and CH2 (this line used in stereo).
DATA3 - CH3 and CH4
DATA4 - CH5 and CH6
DATA5 - CH7 and CH8.

As you have only 2 channel stereo, you have only DATA2 (CH1 and CH2).
I2S bus (WCLK, BCLK, DATA) going to both chips.

You need to set all the DAC's output of the 1st chip, to use CH1, setting all registers 38-41 to 0x00.
The 2nd chip you have to set to use CH2 (38-41 = 0x11).

P.S. I understood you point - they used the word "input" instead of the word "channel" in the registers description, and you think that this is related to spdif inputs.

What to do, this is ESS, not TI or AD, and of course not Microchip (the best DS I ever seen, before I stopped to used them, 10 years ago).
And it is good that this is 9038, as I remember, 9018's datasheet had much more errors and typos.
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Old 16th February 2021, 04:47 PM   #457
syn08 is offline syn08  Canada
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Yes, that's exactly my confusion. So you are saying that in PCM mode "channel 1" and "channel 2" are L/R on digital input 2, right? Then "channel 3" and "channel 4" are L/R on digital input 2, etc...

Thanks!
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Old 16th February 2021, 04:55 PM   #458
syn08 is offline syn08  Canada
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Quote:
Originally Posted by capslock View Post
You mean slightly worse in terms of THD?

Actually, having seen QA-Matts posts about the prototype QA 402 with PCM4220 driven by an analog oscillator, the PCM also seems to have stellar THD performance (HD2 at -128 dB for +6 dBV input), and unlike the AK5374A, it degrades more gracefully near full scale. What remains is a lowish noise corner:

Sneak Peek: The QA402 - #24 by matt - QuantAsylum Forum
Yes, AK5572 is slightly worse (about 2 dB) in terms of THD. THD+N in particular @1KHz is better by the same amount, but this is not really relevant due to noise shaping in the AK5572.

The guy(s) who decided to implement noise shaping for audio in order to feed the SNR war (since there is no real benefit in doing this, beyond the numbers in the datasheet) should be hanged in public.
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Old 16th February 2021, 05:10 PM   #459
altor is offline altor  Israel
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Originally Posted by syn08 View Post
Yes, that's exactly my confusion. So you are saying that in PCM mode "channel 1" and "channel 2" are L/R on digital input 2, right? Then "channel 3" and "channel 4" are L/R on digital input 2, etc...

Thanks!
You are welcome.
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Old 17th February 2021, 05:31 PM   #460
douggoldberg is offline douggoldberg  United States
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Alex, still using my trusty JKGen. What ever happened to JKGen 2?
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