Hi,
It is my second project of DAC, first was on AK4499EQ but after fire in AKM factory projest is useless. Now AK4499EQ chip is to expensive, over 1k USD in Ebay. Now afrer relese new chip on Munich AudioShow I downloaded Datasheet and started designing the new DAC on AK4499EXEQ.
DAC will be Dual Mono, one PCB DAC + Power Supply - one chanell. DAC will be working in Asynchronous mode.
Now it looks like this:
It is my second project of DAC, first was on AK4499EQ but after fire in AKM factory projest is useless. Now AK4499EQ chip is to expensive, over 1k USD in Ebay. Now afrer relese new chip on Munich AudioShow I downloaded Datasheet and started designing the new DAC on AK4499EXEQ.
DAC will be Dual Mono, one PCB DAC + Power Supply - one chanell. DAC will be working in Asynchronous mode.
Now it looks like this:
It is possible to send I2S signal directly to DAC PCB via pins header and write dedicate soft for DAC for this option. There are many solutions
DAC will be full dual mono. I2S signal form Input PCB will be send to each DAC chanell via digital isolator. One PCB DAC and one PCB Power Supply - One chanell. That was main goal.
DAC will have 6 imputs:
-USB
-3 x SPDIF
-2 x COAX
Every necessery options will be possibility to change from display with buttons and encoder.
Input PCB comes form previous version of DAC on AK4499EQ.
Thank You
Attachments
So you did the board also by your own, cool. So you also do the software driver or are they based on an open source project?Every necessery options will be possibility to change from display with buttons and encoder.
Input PCB comes form previous version of DAC on AK4499EQ.
Thank You
Generally I did software by my own in STM32CubeIDE but OLED library I took from from github.
Good crystal oscillator, parts and PCB layout can do more than complex jitter system correction.
OPA1612
USB converter is my version of Amanero. Regular version has some compromises in oscillators, power supply. I use better parts and designed converter on 4 layer board.
I used OPA1612 and analog schematic comes form datasheet.
EQ version has 4 chanell so has 4 capacitors. EX version has 2 channells.
Not quite clear what would be considered 'complex jitter system correction?' ASRC? Reclocking? Something else?
Should be something more complex than already used custom made Amanero solution.
I agreed that will be unnessary.
DAC will be working on asynchronous mode. Using Crystek oscillator jitter is not a problem in that low frequency. I prefere to pay more attencion on other things like looks on current flow, correct placing of tej components, propper PCB layout, PCB stackup, good power supply, etc. That is my philosophy of work.
Please tell me more about jitter issue.
Please tell me more about jitter issue.
Jitter (particularly close-in phase noise) can have various effect on perceptual sound quality. Usually dacs sound better when operated in fully synchronous mode, including synchronous with the USB board. The typical way of making asynchronous mode work is to use ASRC. However, ASRC needs a type of PLL sometimes referred to as poly-phase locked loop (PPLL). It turns out that PPLL is more stable than a typical PLL, yet ASRC can at best only attenuate jitter not eliminate it. PLLs can also be sensitive to power rail noise. Such noise can cause additional jitter effects in ASRCs. Therefore synchronous mode operation can be lower jitter, at least if well implemented.
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