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MP3 player Model

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BobW

Active Member
I have the version that includes an LED display. I paid about the same price for it.
http://www.dx.com/p/1-5-led-mp3-pla...-controller-fm-usb-sd-3-7v-94814#.VGqNcCgxJMI
On mine, the repeat function does continuously loop the song over and over. There are actually two options:
1. Loop one song continuously, or
2. Loop the entire library continuously.

The one thing that I don't like about these units is that they don't have a shuffle play option.

Here are some notes that I made on these units:
http://electronbunker.ca/DL/MP3_Player_Notes.pdf
 

4pyros

Well-Known Member
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Bob; thanks for the info, it looks similar to mine.
Do you know what the main chip is?
 

BobW

Active Member
I just realized that the last page was missing from the notes. I've uploaded a new copy of the notes. The last page lists the major components:

Major Components

Main controller & MP3 decoder: GPDS209A-001D (possibly Amtel clone)
On board EEPROM memory: 24C02
FM tuner: Beken BK1080
Audio Power Amp (2 ea.): Power Analog PAM8002

I have a schematic for what appears to be a similar MP3 Player, which is how I managed to deduce the resistor values for the control functions. I'll see if I can find it, and post a link.

Edit:
Found it:
http://www.chipkingdom.com/upfile/20111211793464876.pdf
 

BobW

Active Member
Yes. There are dozens of different faceplate styles, but all having the same circuit. Considering that these were designed for panel mounting, I'm curious about what product they were originally intended to be used in.
 

4pyros

Well-Known Member
Most Helpful Member
Seen similar ones in self powered speakers.
Most sites selling them are catering to the DIY crowd.
 

4pyros

Well-Known Member
Most Helpful Member
I just realized that the last page was missing from the notes. I've uploaded a new copy of the notes. The last page lists the major components:

Major Components

Main controller & MP3 decoder: GPDS209A-001D (possibly Amtel clone)
On board EEPROM memory: 24C02
FM tuner: Beken BK1080
Audio Power Amp (2 ea.): Power Analog PAM8002

I have a schematic for what appears to be a similar MP3 Player, which is how I managed to deduce the resistor values for the control functions. I'll see if I can find it, and post a link.

Edit:
Found it:
http://www.chipkingdom.com/upfile/20111211793464876.pdf
Thanks again Bob.
Some how I missed this post.
You have provided More info on these units than I could have hoped for.
How did you get the schematics?
I seems the audio is taken right from the main controller D/A output with just a small coil and cap to remove the DC components.
As you noted it is not true line level, but how is the sound Quality?
 

BobW

Active Member
I can't remember how I found the schematics. Just a bit of creative googling, I guess. Also, I don't remember what prompted me to suspect the main IC to be an Amtel part (or clone), but something I ran across in my searches, must have suggested it.

Sound quality is fine except for some bass roll off starting at about 120 Hz. It was obviously intended to drive tiny speakers, and they didn't want it to rattle the cones. However, if you use the line outputs followed by the preamp circuit that I included in the notes, and using that to drive another amplifier, then the audio is pretty good. Considering that the player has a number of different equalization settings, it's a shame they didn't provide one that is flat. I should also point out that my preamp circuit includes a 560 pF capacitor which is there to compensate for what appeared at the time to be an overly hot high end. I later concluded that it may not have been the fault of the mp3 player, but rather the amplifier that I had connected to it. So the 560 pF capacitor could be omitted.
 

4pyros

Well-Known Member
Most Helpful Member
Ok so I got mine a short time ago and am now playing with it. I will report back latter as to weather or no it will suit my needs.
 
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