Dual Mono DAC AK4490/AK4497

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themystical

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Joined 2006
I have now written some Arduino code and running the DAC dual mono. There is a big step up in base performance and sound density.
The difference between running two DACs in stereo mode in parallel and running dual mono appears to be mainly in imaging accuracy with the dual mono being better in this respect.


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cal1sto

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Joined 2015
Running the AK4490 in software control mode give you the ability to use the pcm and dsd mode, I use also the MCLK set to low to reset the internal dac timer only when the master clock should be changed this way you reduce the click noise because on hardware mode you should use the reset pin and this initiate the dac to its default value and this way produce every time the initial pop noise. In hardware mode you could as example put a little relay or electronic similar ci to stop output before changing the settings and restore it just before playing.
Really interesting to see you could trigger the dac with an arduino , what do you use as master clock ? And did you cover all frequencies 32khz to 768khz ?

Currently I have my firmware ready with a little personalized oled display , covering all frequencies in pcm mode and just fitting a little bit with the dsd mode to get the output clean ... wait on a logic analyzer to find out where the code or timing as to be ajusted ... but anyway the XMOS is really powerfull 😉
 
T

themystical

Member
Joined 2006
cal1sto said:
Running the AK4490 in software control mode give you the ability to use the pcm and dsd mode, I use also the MCLK set to low to reset the internal dac timer only when the master clock should be changed this way you reduce the click noise because on hardware mode you should use the reset pin and this initiate the dac to its default value and this way produce every time the initial pop noise. In hardware mode you could as example put a little relay or electronic similar ci to stop output before changing the settings and restore it just before playing.

Really interesting to see you could trigger the dac with an arduino , what do you use as master clock ? And did you cover all frequencies 32khz to 768khz ?



Currently I have my firmware ready with a little personalized oled display , covering all frequencies in pcm mode and just fitting a little bit with the dsd mode to get the output clean ... wait on a logic analyzer to find out where the code or timing as to be ajusted ... but anyway the XMOS is really powerfull [emoji6]
Click to expand...



I have the DAC sampling rate to auto detect and this works fine. My Nvidia Shield only outputs 192k which works very well. I suppose I could connect my laptop and use Foobar to up sample to 784k and check whether it is working. I could possibly also test out DSD with the couple of sample tracks I have but all this is of academic value as I I don't have any proper music higher than 192k or in DSD so I have lost interest,
I do need to get rid of the click noises and for that I have ordered a 4 channel 5v relay to use as a mute relay on the analogue outputs.i am planning to use the zero detect function of the chip to detect no data input and isolate the analogue outputs whenever this condition exists
 
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themystical

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Joined 2006
So guys I am really struggling badly trying to get rid of really loud clicks and pops I get with this DAC in conjunction with my Amanero and Nvidia Shield. I tried the special AKM firmware created by Amanero to no avail.
I seem to have tried everything on the basis of the zero data detection pin of the chip. I have configured this via serial for both left and right channel detection to work in "and" mode. The idea being to soft mute the DAC when there is no input signal. This actually seems to make the clicks louder. I tried an external mute relay using the same principle and this also makes the clicks worse. Don't know where to go from here. Any ideas anyone?


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themystical

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dexterelu said:
@themystical: Can you get a screenshot of the click/pop on a scope? Also, it would be interesting to see the click/pop on two scope channels. One for the DAC output and one for the AMP output.
Click to expand...



Unfortunately, I don't have a scope. I am making some progress in correctly configuring the external mute relay circuit to stop the clicks and pops on power up as well as normal operation. Final testing yet to be done but I feel confident that I have cracked the issues.
 
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formatcd3

Member
Joined 2015
cal1sto said:
I got already the vumeter runing (move right by sound input) and could now put on the Oled some information dynamicaly, i will today test and integrate the specific AK4490 configuration to configure on need the DAC register. I hope to have the basic firmware ready til end this week (with volume up/down and filter selection)
After i will optimize everything for performance to be able to reach the max power this DAC is able to deliver -> to be ready for the AK4497 when AKM deliver me the sample.
Click to expand...

Very interesting project. Did you manage to get your AM4497 samples yet?
 
C

cubano

Member
Joined 2015
themystical said:
I have now written some Arduino code and running the DAC dual mono. There is a big step up in base performance and sound density.
The difference between running two DACs in stereo mode in parallel and running dual mono appears to be mainly in imaging accuracy with the dual mono being better in this respect.


Sent from my iPhone using Tapatalk
Click to expand...

Can you show us the scheme used for the dual mono, please?
I use two pcb diyinhk ak4490 and I did a test in dual mono. But I have no difference between my stereo and dual mono measures with RMAA. I think there is a problem with output stage.
 
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Green77

Member
Joined 2007
Hi all.

Just finished a DIYINHK ak4490 board. With a standard 7812/7912 psu for op and a lm317 for 3.3v. On the 5v in i'm use a low noise psu set to 6.8v.
I use the xmos USB card from DIYINHK too.
Everything works, but the sound is really bright.
Anyone have the same problem with this pcb?

Best regards //Daniel
 
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themystical

Member
Joined 2006
Daniel it certainly doesn't sound bright in my set up but I do find that there is no detail missing. I use super regulators for power supplies. In dual mono form this is one of the best sounding DACs I have heard. Better than or equal to the dual mono es9018 DAC I had.
I suppose you can fine tune the sound by use of different op amps. The NE5532 is quite dull sounding compared to the LME79210 but the best I have heard is ADA4898-2.


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cubano

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Joined 2015
i tested ne5532, OPA2134PA, ad827, ada4898-2, sonic imagery si994. I love ada4898-2 and si994. si994 is the best for me but is very expensive. I would like test the LME79210 and other on my next LPF. The dac ak4490 diyihnk is not bright at home. Themystical ,have you use a default capacitor?
 
T

themystical

Member
Joined 2006
cubano said:
i tested ne5532, OPA2134PA, ad827, ada4898-2, sonic imagery si994. I love ada4898-2 and si994. si994 is the best for me but is very expensive. I would like test the LME79210 and other on my next LPF. The dac ak4490 diyihnk is not bright at home. Themystical ,have you use a default capacitor?
Click to expand...

I have used the Panasonics supplied by DiyinHK. They are good quality. I have put bigger values for the main reservoir capacitor for each supply. 470uF Panasonic FM. No capacitors in the signal path.
Never heard of the SI994 op amp., will google that.


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cubano

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Joined 2015
Can you confirm? you put capacitor 470uF Panasonic FM on power? (see below)
 

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