Computer Audio Blasphemy, nige tries Another SD Card Player

[Fran]

I have a some of these and they are worth the cost. Don’t seem to like being filled up though.
https://rover.ebay.com/rover/0/0/0?mpre ... 0939143730


Sent from my iPhone using Tapatalk

Thats the one I have as well....

[jkeny]

The SLC cards give quite a good lift in SQ - enough to make me buy one!!

Right, I hadn't herad them so this is good to know

You are more than welcome to the dead card, I think I measured the push buttons as just sending a high or low TTL signal. Also, Pearse has an annotated diagram of the card with pinouts marked. Very handy to print out at A3 and have it as a reference.

Haha, like me - throw nothing out :). I reckon the way to control the push buttons would be to use small relays to connect across electrical points of the switches & control the relays with signal from EPS or whatever control circuit?. I think I've seen Pearse's pinouts before & stored them somewhere?

Whats availability like on those cards now?

Seem to be still available

BTW, a link to a SD player last year showed control of SD playback using a mobile app - pretty much what I'm suggesting - it's basically substituting the crappy screen & push button interface of the SD player for a much better UI on a mobile phone

https://item.taobao.com/item.htm?spm=a2 ... t=6#detail



But the SD player hardware itself is not upto scratch for a number of reasons not least that the bluetooth receiver is directly connected to the SD card so noise intrudes

I have the app but not the hardware - the app doesn't connect to other bluetooth devices so it probably relies on some code being received from the SD player's bluetooth. I have decompiled the APK into Java source code produced by a conversion utility but I'm not a Java programmer. Anybody out there interested in having a look at the source code - I reckon it needs some changes apart from the code lock that it seems to have?

[jkeny]

Yea, the one Pearse has is likely the best hardware - if we could get a remote control app work like the BlutoothBox app, it would be perfect?

So, again my idea would be to copy music library to SD card & the control app would use a mirror of this folder/file structure to navigate through & control playback but not play on the phone, just send the correct codes to the SD card player for navigation/playing - same codes as the remote uses. I know there are probably lots of creases to iron out in something like this but only trying it in practise would reveal what tweaks are needed.

I reckon a WifI rather than Bluetooth connection would be better as the underlying premise for this working correctly is that the current position pointer on the phone app is correctly matched to the current position pointer on the SD card i.e they are both pointing to the same file - that way navigation & playback are correct.

With BT the signal is too fragile & distance limited so it's far easier to lose the correct position & go out of synch with the SD card player. I reckon a reset function is needed, anyway, that allows resetting both pointers to some mutually known position of the file structure

[Fran]

I think I was using an ESP8266 to send a high signal to mimic the button presses.....

[jkeny]

I think I was using an ESP8266 to send a high signal to mimic the button presses.....

Yea, sorry ESP, not EPS as I posted & this is a WiFi board - it looks like that's what they use on the SD player Pearse has?
It may be that directly connecting the switch electrical contacts to the ESP, may have put some RF noise on the switch pcb tracks which I think go straight into ARM chip - maybe that's what killed the player? Would be interesting to see how Pearse's device does it - how the remote working through the WiFi receiver controls the switching?

Anyway, an electrical not mechanical relay across the switch points would isolate any/most noise intrusion

[Sligolad]

I have missed out on recent posts here but will catch up in the coming days.
I got the Player recently and have only had the chance to listen over SPDIF so far and it performs very well off the remote.
I thought i had an DVI to I2S out module but could not find it so ordered another one off Audioholics in France so should have it soon.

I could probably tap into I2S on the board but not feeling up to messing with it just yet.
The remote and player connect over 2.4g wireless and perform flawlessly though there are some chinese characters which needed translating.
The units used are these https://www.ebay.com/itm/2-4G-Wireless- ... 1775931889
The remote displays artists and tracks in english as they are written on the SD Card and once you figure out the buttons are easy to navigate.
I will probably 3D print a nice fit form remote casing at some point for the remote to replace the sharp edged container.

Processor used is https://www.st.com/content/st_com/en/pr ... 429zg.html

SPDIF is handled by https://www.ti.com/lit/ds/symlink/dit4192.pdf

I2S goes through Quad buffer https://assets.nexperia.com/documents/d ... HCT125.pdf

Then through LVDS Quad Driver https://www.analog.com/media/en/technic ... DN4667.pdf

Clocks seem to be from Taiwan company TXC https://www.txccrystal.com/images/pdf/9b-accuracy.pdf

Other than that there are 5 separate power supply lines each using what look like little wire wound 221 inductors 2 tantalum Caps and this LDO unit http://www.ti.com/lit/ds/symlink/tps7a47.pdf

Will post pics soon.

[tapatrick]

I have missed out on recent posts here but will catch up in the coming days.
I got the Player recently and have only had the chance to listen over SPDIF so far and it performs very well off the remote.
I thought i had an DVI to I2S out module but could not find it so ordered another one off Audioholics in France so should have it soon.

I could probably tap into I2S on the board but not feeling up to messing with it just yet.
The remote and player connect over 2.4g wireless and perform flawlessly though there are some chinese characters which needed translating.
The units used are these https://www.ebay.com/itm/2-4G-Wireless- ... 1775931889
The remote displays artists and tracks in english as they are written on the SD Card and once you figure out the buttons are easy to navigate.
I will probably 3D print a nice fit form remote casing at some point for the remote to replace the sharp edged container.

Processor used is https://www.st.com/content/st_com/en/pr ... 429zg.html

SPDIF is handled by https://www.ti.com/lit/ds/symlink/dit4192.pdf

I2S goes through Quad buffer https://assets.nexperia.com/documents/d ... HCT125.pdf

Then through LVDS Quad Driver https://assets.nexperia.com/documents/d ... HCT125.pdf

Clocks seem to be from Taiwan company TXC https://www.txccrystal.com/images/pdf/9b-accuracy.pdf

Other than that there are 5 separate power supply lines each using what look like little wire wound 221 inductors 2 tantalum Caps and this LDO unit http://www.ti.com/lit/ds/symlink/tps7a47.pdf

Will post pics soon.

Super find. Thx for sharing.

[Sligolad]

[Sligolad]

[nige2000]

Has it got potential pearse?
Ie does it sound as good as the one we used stock.?