I'm building a DAC using AK4493 and AK4118 chips. I'm mostly following the datasheets, evaluation manuals and other designs that have been discussed here, but I'm confused about MCLK. This section in the datasheet provides the clock examples, and I would like to use a 24.5760MHz clock provided by AK4118. What happens if the source material is either 44.1kHz or 48kHz but the clock remains fixed?
The MCLK out from the AK4118 should be the recovered clock. Then the clock output of the AK4118 will follow the source material. For 44.1 kHz it should output 22.5792 MHz and for 48 kHz it should output 24.576 MHz. To get this, you must set the AK4118 to output a clock of 512fs.
Please note that an external clock on AK4118 is not the MCK AK4118 outputs in receiver mode. Instead AK4118 always outputs a clock recovered using PLL. External clock is used in receiver mode for sampling frequency detection only and as MCK output in transmitter mode.I would like to use a 24.5760MHz clock provided by AK4118.
Unless you use an oscillator XTL0 and XTL1 of AK4118 should be connected to VDD to use channel status for sampling frequency detection.Ok, this is the schematic I've come up with.
LP2992 has highish noise. NCP163 is cheaper and has much lower noise.
Ok, this is the schematic I've come up with.
Sallen-Key is not a good solution here,MFB is much better.
I initially went for the NCP163 but then I saw it has a maximum input of 5.5V. I would need an adjustable regulator to provide that.Unless you use an oscillator XTL0 and XTL1 of AK4118 should be connected to VDD to use channel status for sampling frequency detection.
LP2992 has highish noise. NCP163 is cheaper and has much lower noise.
VREF supplies are critical for AK4493 so I would use lower noise regulator on those. Other supplies are less important.
Are the filters from the datasheet adequate?
Yes, for simple solution.
But, this is not the best.
I used few circuits like these:
Attachments
Holding my thumbs and will watch this topic as I want to build own 3x 4493 DAC for active xo. Hope to get some more info🙂
👍
👍
What "info" do you need?
I've made 6/8ch DAC with 3x or 4x 4493 in the past (end after the fire at AKM factory, it was changed to 6/8ch with 3x or 4x ES9038q2m).
I've made 6/8ch DAC with 3x or 4x 4493 in the past (end after the fire at AKM factory, it was changed to 6/8ch with 3x or 4x ES9038q2m).
Nice! How you see them comparing 4493 vs es9038q2m? For example how to sync all 3 DACs.. just share mck?
How you see them comparing 4493 vs es9038q2m?
As for me, 4493 is better for DSD, while for PCM it is hardly to say what is better, they sounds a bit different.
For example how to sync all 3 DACs.. just share mck?
Not only MCLK, but also BCLK and WCLK (for PCM).
And control (I2C/SPI), of course.
P.S. Of course DSD is not relevant for XOm just for multichannel (5.1, 7.1)
May I ask if there is there some reason why you are choosing to use SPDIF and a recovered MCLK? Reason I ask is there is expected to be some jitter penalty in that case. IIRC, especially so if using AK4118.I'm building a DAC using AK4493 and AK4118 chips.
Last edited:
SPDIF because I'm connecting it to a device that has this output.May I ask if there is there some reason why you are choosing to use SPDIF and a recovered MCLK? Reason I ask is there is expected to be some jitter penalty in that case. IIRC, especially so if using AK4118.
About MCLK, given the explanation in the first posts this is pretty much how it should work. The datasheet is pretty vague and I don't fully understand how it works.
I also considered other transciever chips but I thought I'd go with their offering. But I'm open to suggestions since this is my first time in the digital audio world.
Okay. Dacs usually tend to work best (lowest jitter) if there are local crystal clocks at the dac. A PLL recovered MCLK is never as good as a local crystal clocking.
There are two well-known solutions, which are ASRC (AKM makes a good one, AK4137), or else a FIFO buffer. The most common and probably lowest cost solution is ASRC.
The ASRC chip goes between the AK4118 and the AK4493. You need at least one crystal clock too. NDK SDA series are pretty good.
Also need a microcontroller to program the the AKM chips at power on.
There are two well-known solutions, which are ASRC (AKM makes a good one, AK4137), or else a FIFO buffer. The most common and probably lowest cost solution is ASRC.
The ASRC chip goes between the AK4118 and the AK4493. You need at least one crystal clock too. NDK SDA series are pretty good.
Also need a microcontroller to program the the AKM chips at power on.
That gets a little too involved for a first project.
What about a clock recovery circuit? I saw one here but the chip isn't available anymore: https://www.dimdim.gr/2020/04/dual-mono-ak4493-dac-mk-ii/
What about a clock recovery circuit? I saw one here but the chip isn't available anymore: https://www.dimdim.gr/2020/04/dual-mono-ak4493-dac-mk-ii/
What chip?I saw one here but the chip isn't available anymore
PO74G374? Huge overkill.
Use 74ALVC374, but this is also overkill.
How do you want to make XO with SPDIF input?
There are SPDIF receiver chips with lower jitter than AK4118.That gets a little too involved for a first project.
Still, you will need to learn how to program a microcontroller at some point, if you don't already know how. An Arduino is good enough, and easy to program.
If you are interested, I have some links to posts explaining use of Arduino for controlling dacs.
Last edited:
- Home
- Source & Line
- Digital Line Level
- AK4493 + AK4118 DAC