Using Nokia BH-503 bluetooth headset to make a bluetooth speaker.

Discussion in 'The Projects Forum' started by flash11, Oct 4, 2015.

  1. flash11

    Thread Starter New Member

    Oct 4, 2015
    Hey there guys! I am new to this website. I need some help to turn the Nokia BH-503 bluetooth headphones into a music adapter for a portable speaker. There are a couple of reasons I want to do this. The bluetooth headphone battery is not functioning anymore so the headphone is just sitting unused and because I have a speaker laying around as well. All I'll have to spend on is the amp.

    The plan is to use the headphone PCB to receive audio from my phone over bluetooth. Then feed the output of the headphone PCB to a amplifier. I'll be using the PAM8403 which is available on ebay.
    Here is a picture of the PAM8403 amp-

    I have a speaker driver from my old computer speakers which is rated at 1.5W. Considering that the amp is rated for 3W per channel the driver should do fine if I don't set the gain too high.

    This is what the PCB of the headphone looks like:

    As you can see the headphone PCB has stereo output which I will connect to the left and right inputs of the amp. Assuming that its fine to do that. Correct me if this is not the right way to do it.

    The amp has stereo output. But, I want mono output because I will be using a single speaker.

    So, my question is whether there is a way to get mono output from a single channel?

    Any help is appreciated :)
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    Welcome to AAC!
    Google 'resistive mixer'.
  3. flash11

    Thread Starter New Member

    Oct 4, 2015
    I googled 'resistive mixer' and found this:

    So, I'll connect resistors to the positive right and left channels of the headphone PCB and connect the other ends of the resistors to positive left input of the Amp. Then splice the negative left and right channels together and connect them to the negative left input of the Amp. This should be it right?

    BTW, what is the value of resistor you would suggest and why?

    Thanks for your help!