Dual Mono DAC AK4490/AK4497

[kukynas]

Interesting spec and diagram. I had quick look on it and DIX9211. DIX knows nothing about DSD, its only PCM or passthrough. DSD inputs should be connected on Port0 & 1 of the board which are GPIO B & C of the DIX. When switched by the PIC the DIX act as a passthrough from Port0 or 1 to the 4 I2S/DSD input pins of the 4490s.
Two options :
a/ there's no PCM/DSD detection , the port 0 and 1 have to be configured before usage to DSD or PCM, then when you switch to these inputs the 4490 is setup accordingly.
b/ the PIC does the detection by analysing the frequency of BICK connected to port C0 of PIC. Frequency for various fs are well know for PCM and for DSD, this may be analysed via software (I've to do some calculation in order to check if we have differents frequency for each fs and mode). The display on page 14 saying 'Unknown I2S' let me think this is reasonable to admit that PCM/DSD detection is made to BICK analysis. In addition port C0 is connected internally to Timer 1 of the PIC, which may be useful for frequency analysis. If true it's smart ! but those are only assumptions 🙂

nice find if it's true, I wasn't aware of any standalone chip other than FPGA to do the autodetection but can confirm my A20H can autodetect and lock DSD over SPDIF

 

[choucroutemelba]

I've check the simpleDACAK4490 schematic and came to the same conclusion.
I think the b/ is right.

 

[choucroutemelba]

another Japanese site with audio kits including dual AK4497 and ES9038PRO over here

Kukynas did you try easyaudiokit products ?
What do you think about ?
Did they ship overseas ?

I can't find the capacitor brand ?

 

[ChuckT]

Does your AK4495 board have an on-board uC? Does it also have the XMOS on-board?

Because the 4495 does not support DSD if it is not controlled by a uC (p. 44 of the AK4495 datasheet).

Here's the board, it does have a controller.
There is also jumper to set the DSD/PCM, but I don't need to switch the required jumper for the DSD/PCM output. Strange.

 

[kukynas]

Kukynas did you try easyaudiokit products ?
What do you think about ?
Did they ship overseas ?

I can't find the capacitor brand ?

nope I haven't, I couldn't find any DIY version of dual AK4497 with proper implementation of muting relay and programmed delay for PCM/DSD switching to avoid pop/clicks, that's why I bought ready made DAC from Gustard which I plan to upgrade slightly

 

[Dimdim]

Here's the board, it does have a controller.
There is also jumper to set the DSD/PCM, but I don't need to switch the required jumper for the DSD/PCM output. Strange.

If your XMOS board does not signal your DAC every time you change signal type, I don't see how this could work.

Are you sure that HQPlayer doesn't convert DSD to PCM?

 

[Sergelisses]

Here's the board, it does have a controller.
There is also jumper to set the DSD/PCM, but I don't need to switch the required jumper for the DSD/PCM output. Strange.

Hi
Where i can find this board ?

Thanks
Serge

 

[kukynas]

Hi
Where i can find this board ?

Thanks
Serge

here is whole thread about dual version of the board (same designer)

 

[choucroutemelba]

nope I haven't, I couldn't find any DIY version of dual AK4497 with proper implementation of muting relay and programmed delay for PCM/DSD switching to avoid pop/clicks, that's why I bought ready made DAC from Gustard which I plan to upgrade slightly

What do you meen with "programmed delay for PCM/DSD switching" ?

What do I beware off exactly ?

 

[kukynas]

from datasheet...

The AK4497 can perform D/A conversion for either PCM data or DSD data. The DP bit controls PCM/DSD mode. When DSD mode, DSD data can be input from the #16, #17 and #19 pins if DSDPATH bit = "0" and DSD data can be input from the #3, #4, and #5 pins if DSDPATH bit = "1". The AK4497 must be reset by setting RSTN bit = "0" when PCM/DSD mode is changed by DP bit or when DSD signal input pins are changed by DSDPATH bit. It takes about 2 ~ 3/fs to change the mode. Wait 4/fs or more to change RSTN bit after changing these settings.

■ [FONT=Arial,Arial][FONT=Arial,Arial]D/A Conversion Mode Switching Timing
[/FONT][/FONT]Figure 22 and Figure 23 show switching timing of PCM/EXDF and DSD modes. To prevent noise caused by excessive input, DSD signal should be input 4/fs after setting RSTN bit = "0" until the device is completely reset internally when the conversion mode is changed to DSD mode from PCM/ESDF mode. DSD signal should be stopped 4/fs after setting RSTN bit = "0"until the device is completely reset internally when the conversion mode is changed to PCM/EXDE from DSD mode.

during internal reset click/pop sounds occur so if you do not have MCU programmed for these 4fs delay of muting you will hear this pop/click after every change of PCM/DSD mode and it's very annoying

 

[androa76]

Still no infos when blue smpcb ak4497 board will be out. First completed ak4497 dacs were sold ant now...silence.
Any informations , maybe kukynas ?

 

[kukynas]

I assume there's still big shortage of AK4497 chips on the market so I think that's the only reason why we don't see more of them including dual version

 

[nautibuoy]

Are you sure that HQPlayer doesn't convert DSD to PCM?

HQPlayer doesn't convert DSD to PCM by default (though I think you can tell it to do so if that's what you require). One of HQPlayer's fortes is very high quality DSD playback output, whether from native DSD media or upsampled from PCM files.

 

[Dimdim]

What I meant to write was "are you sure that HQplayer isn't converting DSD to PCM in your setup?".

My bad..

 

[choucroutemelba]

from datasheet...
during internal reset click/pop sounds occur so if you do not have MCU programmed for these 4fs delay of muting you will hear this pop/click after every change of PCM/DSD mode and it's very annoying

Okay, very clear . Thank you

A think that would not happened while switching PCM/PCM.

 

[ChuckT]

What I meant to write was "are you sure that HQplayer isn't converting DSD to PCM in your setup?".

My bad..

Actually, its converting PCM to DSD.

 

[Dimdim]

In that case, I assume that you have set your DAC's jumpers for DSD, right? That would make sense.

 

[kukynas]

Okay, very clear . Thank you

A think that would not happened while switching PCM/PCM.

correct, only in case of PCM/DSD and back...

 

[nautibuoy]

Ah, sorry.

What I meant to write was "are you sure that HQplayer isn't converting DSD to PCM in your setup?".

My bad..

 

[surfchampion]

If I understand correctly what you are saying, there is no "DSD/PCM selector pin" on the AK44xx DACs. This DSD/PCM signal needs to be routed to a uC which will in turn send the necessary commands to the AK44xx DAC to switch it to either PCM or DSD mode.

I'm pretty sure that Ian's reclocker will provide a way to signal the AK's uC of the signal type. You could ask him.

Yure right. Ian answered:

Quote:
Originally Posted by surfchampion

View Post

Thank you, Ian for explanation!
especially about OCXO

There are kind of internal signal in the MC FIFO which we will be able to use as drive signal for the DSD/PCM mode switch of AK4495/97 DAC? I mean DSD/PCM detection.
This will be kind of solution for non-automatic DACs.

Thanks surfchampion, that a very good point.

There will be a active high signal called DSD to indicate DSD format, just for DACs without DSD/I2S auto-detect function. This signal will also be isolated.

Ian