Vintage Headphones meet Bluetooth

Wireless & IoT
1

Shalom, my friends.

I am a beginning electronic hobbyist, my skills have potential, but for this next project I will need some expert advice.

I want to combine a 1960’ Koss Headset with a bluetooth headset making it wireless for my a2dp enabled touch phone (omnia i910).

I plan on desodering the wires running from the chipset in the bluetooth to the speaker and resodering them to the Koss.

I know I will need to up the voltage and soder in a rechargeable power supply. I am not sure how to go about doing this. Could I get another battery with higher voltage but the same amps, will this work?

I have:

  1. A koss headphone (no mic)

  2. Helping Hands

  3. Trusty sodering iron.

How do I keep the clarity of the signal while upping the voltage? What headset do I need to get stereo?

Can one of you guru’s recommend parts?

2

Not entirely sure what you’re asking, but it sounds like you simply wish to take the audio out from your bluetooth headset (which would normally be connected to its speaker headphones) and plug your ‘vintage’ headset into it? correct?

This really isn’t anything to do with RF since you are not changing the ‘bluetooth’ part at all, this is really just an analogue thing.

You mention ‘upping the voltage’. This all depends on the impedance of your vintage headset :slight_smile: I would measure the resistance of the original bluetooth headset speakers, and do the same for your vintage headphones. I’m willing to bet your older headphones have a much lower impedance. All you really need is a headphone driver, with a low, adjustable gain. The power of the driver depends on the impedance of the headphones its trying to drive. These days its usually 32ohms, but 16, or even 8, were used in the past.

The reason I mentioned ‘adjustable gain’ is because headphones amplifiers don’t’ always ‘amplify’ the signal. They are generally current amplifiers, whose voltage output is similar to the input, but with an output stage capable of driving very low impedance loads. Look for a stereo headphone amplifier chip, such as the TDA2822, which is a 1W-1W stereo power amplifier.

Please note that bluetooth headsets/headphones tend to have very small speakers because they are portable, and try to keep power consumption to a minimum, thus making the battery smaller, keeping it ‘lightweight’.(this is why they are rarely ‘loud’). If you buffer the audio out with a power amplifier to drive larger speakers (more current, and therefore, more power) the power consumption will go up and the battery life will drop like a stone. So perhaps consider using a larger capacity battery.

Buridecode.