Don't use this eBay Bluetooth Dongle to DIY BT HPs
Jan 3, 2014 at 7:45 PM Thread Starter Post #1 of 5

inline79

100+ Head-Fier
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Hello fellow DIYers:
 
If you're thinking of making your own Bluetooth headphones, don't buy this A2DP Bluetooth dongle from ebay:
 
http://www.ebay.com/itm/Wireless-Bluetooth-Audio-Music-Receiver-3-5mm-A2DP-For-iPod-iPad-iPhone-MP3-PC-/290920955046?pt=Other_Tablet_eReader_Accessories&hash=item43bc3d7ca6
 
I took the gamble and lost this time.  Though at first glance it does have everything you think you want:  A 3.7V 250mAh battery, an OVC3860 Bluetooth chip w/ battery charging and headphone out, and even a PT2308 IC for a headphone amp.
 
Though easy to pair and it does play music with little noise or interference, the music sounds like crap!  clearly somewhere there is a high pass filter that dumps everything below about 500Hz...   NO BASS!!! GRR!!
 

 
I tried to bypass the headphone amp completely and drive HPs directly from the OVC3860 output, but it still sounded like crap.  So either the OVC3860 output section just sucks or some treble boost got enabled inside that chip.  I don't have enough info about the OVC3860 to go any further...
 
Anyways, pretty good little box, smaller than I could ever put together myself, if only it didn't sound like crap!
 
Anyone else have any experience with the OVC3860 and getting decent audio from it?
 
Jan 17, 2014 at 2:56 AM Post #2 of 5
I don't think it's the OVC3860's fault, but rather the whole circuit itself. Maybe it was designed to conserve its tiny internal Li-ion and underdrive the signal. 
 
I made my own Bluetooth headphones by using the internals from another Bluetooth headphone(!). It even has a microphone for phone calls!
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Jan 17, 2014 at 8:54 PM Post #3 of 5
Thanks vantt1! Cool project. Yeah, I don't blame the OVC, but rather the designer of this board or the programmer of it. The amp also seems to be unnecessary as the OVC has an hp out. There are also aptx proto boards out there, but nothing will be small enough!

Which BT headphones did you start with?
 
Jan 18, 2014 at 12:12 AM Post #4 of 5
They are called 'Ronin Nomaster' Bluetooth headphones. They're just some no-brand budget Bluetooth headphones that sell for $24.
 
Jan 21, 2014 at 12:01 PM Post #5 of 5
I'm thinking of doing a similar DIY project with my Monoprice 8323's.  I currently have this BT receiver in my car and it works well and sounds really good to my ears: http://www.amazon.com/VicTsing-Bluetooth-Receiver-NFC-Enabled-Technology/dp/B00E5CBHCE/ref=sr_1_4?ie=UTF8&qid=1390323362&sr=8-4&keywords=nfc+bluetooth.
 
I cracked it open and the circuit board seems small enough to fit into the earcups of my cans.  I don't think you'll get any attenuated bass as you are with the one you were trying to use.  Bass rocks in the car, and I've wired my headphones to it to test it out and it sounds very close to the sound when wired. It has a lot of features for being $25.
 

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