Computer Audio Blasphemy, nige tries Another SD Card Player

[Fran]

Thanks Randy - there's a bunch of us already listed on the group buy - having heard one of these they make a large difference (although they are fairly costly)

[NUML0G]

The white screen problem is looking like it's linked to the display. I was trying to add a switch to disable the LCD swhen the player is on, there is 2 power inputs for the LCD, one for the backlight and another for display driver, disconnecting the display driver supply causes the same white screen and pressing reboot in this state gives me a red led, I have not actually tested if it can play or not during this but I think its safe to assume this is same white screen state we've been experiencing.

The backlight can be turned off, power is fed through the larger 470 resistor on back of player underneath the display.
Kind of shame the driver cant be disabled aswell, since it could also eliminate some unneeded load and interference on the supply during playback.

[NUML0G]

OK, finally got to the bottom of the white screen problem after months.
It was caused by the IR receiver... I noticed a couple of times the white screen happened after coming close to the player or putting my hand over to change tracks, tbh I think this was pure coincidence since the screen happens completely randomly even when nothing is near it but It did get me thinking about that IR receiver since heat is in IR spectrum. Since there was nothing else to try I removed the sensor and it actually fixed, have gone many hours now without a white screen.

Unless its possible heat sources can interfere with an IR receiver it's probably picking up electrical intereference and sending garbage into the MCU. In the datasheet they recommended 47R+47uf RC filter on the receiver's power input but all it had a 0.1uf cap on the player.

[Fran]

That is a good piece of detective work NUMLOG. If its stable now after another few days of soak testing, then you might have cracked it.

Will you update us in a few days?

[NUML0G]

I left it looping a track for 24 hours straight, pretty confident it's actually fixed now.

[NUML0G]

Using this player with an Ak4497 board from diyinhk has been a little bit disappointing compared to the Soekris DAM1121,
a fairly noticeable loss in detail compared to the diyinhk XMOS I2s board and not nearly as much harshness with XMOS with this ak4497 DAC.
DAM1121 more sensitive to noise but less sensitive to jitter?

The DAM1121 does have FIFO on the input however...
I'm pretty clueless on XMOS and most things digital, whether it is doing some sort of reclocking itself internally with the low jitter NDK clocks since it designed for this purpose unlike the general purpose MCU in this player.
I thought not only because diyinhk have their FIFO adapters for these XMOS boards.

EDIT- On second thought not really sure about the sound quality. the XMOS board has a strikingly different sound signature which is more airy and bright but its hard to say if there truly is more actual detail or resolution. Usually when something has digititus, it is harsh and lacking real detail but neither of these are the case for the XMOS board so its throwing me off.
I think what might be happening is that the AKM4497 board is not very resolving compared to the DAM1121, and all the the subtleties of the SD player are lost and what's left is only a softer and duller sound.

[tims]

OK, finally got to the bottom of the white screen problem after months.
It was caused by the IR receiver... I noticed a couple of times the white screen happened after coming close to the player or putting my hand over to change tracks, tbh I think this was pure coincidence since the screen happens completely randomly even when nothing is near it but It did get me thinking about that IR receiver since heat is in IR spectrum. Since there was nothing else to try I removed the sensor and it actually fixed, have gone many hours now without a white screen.

Unless its possible heat sources can interfere with an IR receiver it's probably picking up electrical intereference and sending garbage into the MCU. In the datasheet they recommended 47R+47uf RC filter on the receiver's power input but all it had a 0.1uf cap on the player.

Hi NUMLOG
Tried your fix on my player and can confirm no crashes after several hours - great fault finding! 👍👍
Cheers

[NUML0G]

Hi NUMLOG
Tried your fix on my player and can confirm no crashes after several hours - great fault finding! 👍👍
Cheers

Nice to hear this is a consistent fix,
btw did you get a remote included with yours?
either I didnt get one or it was thrown with the box by accident.

[tims]

Hi NUMLOG
Tried your fix on my player and can confirm no crashes after several hours - great fault finding! 👍👍
Cheers

Nice to hear this is a consistent fix,
btw did you get a remote included with yours?
either I didnt get one or it was thrown with the box by accident.

No, I didn't get a remote with my order - not that it would be much good now if I did get one ;-).
Anyway, just good to get the player finally working.

[NUML0G]

Just after checking and I was wrong about the display, it does work with display fully unpowered and sounds little better too I think