Retro Beats [DIY Bluetooth Headphones]

This instructable will guide you through my process of making custom Bluetooth headphones.

I chose a classic set of Pioneer SE-50's for this venture.

I picked them up on eBay for 20$ USD.

They were in good shape with exception to a broken headphone chord...perfect.

Parts List:

Pioneer SE-50 Headphones

https://www.head-fi.org

Adafruit Mini Lipo w/Mini-B USB Jack - USB LiIon/LiPoly charger - v1

• I used an old USB charging cable

https://www.amazon.com/Adafruit-Mini-Lipo-Mini-B-J...
3.5mm Stereo Panel Mount Jack

• This will replace the broken micro USB connector on the old charging cable I had.

https://www.amazon.com/kenable-Stereo-Solder-Termi...

Black Plastic Housing 3.5mm Audio Jack

• This will serve as our DC in on the charging board

https://www.amazon.com/Uxcell-10-Pieces-Black-Plas...

KRC-86B Bluetooth Module

https://www.amazon.com/Aideepen-KRC-86B-Bluetooth-...

3V-6V TDA1308 Headphone Amplifier Board AB Amp Preamplifier Module Hot

• Since the output of the KRC-86b is line level, this will boost the signal to headphone volume levels.

https://www.ebay.com/itm/3V-6V-TDA1308-Headphone-A...

ADAFRUIT INDUSTRIES 1578 Lithium Ion Polymer Battery - 3.7v 500mAh
https://www.amazon.com/ADAFRUIT-INDUSTRIES-1578-Li...

Step 1: Main Power and Audio Backbone

I picked these components as quality sound, long use duration, and safety were my primary concerns.

Step 2: Fitment

Opening the headphones up to address fitment concerns.

Step 3: Ready to Rock

The assembly of the circuit.

Step 4: Finale

Each Driver had enough room to fit the components nicely.

I had to add a headphone amp board for sufficient volumes.

I chose a tda 1308

Connection Flow:

1. Lipo Charger [mini lipo v1] + and - OUT to Bluetooth [Krc-86B] Power IN + and -

2. Bluetooth [Krc-86B] Power + and - to headphone amp board Power IN + and - [tda1308]

3. Bluetooth [Krc-86B] audio OUT to headphone amp board audio IN + and - [tda1308]

4. Headphone amp [tda1308] audio OUT + and - to headphone drivers + and - [Pioneer SE-50]

5.1/8 panel connector [not pictured] + and - to the DC IN + and - of the Lipo charger [mini lipo v1]

6. Cell [ Ada Fruit 1578] to Lipo charger [mini lipo v1] header

7. Reassembly.

Step 5: Result

They're a little dirty, however for their age not too bad.

I will be taking them to a shoemaker to see if they can replace this white material and recover the ear pads.

They sound great on classic recordings, however, they lack modern sub bass levels.

I personally enjoyed this project as both a tech and also as an audiophile.

Now if you don't mind, I have a date with The Steve Miller Band and ELO.

I hope you enjoyed this instructable.

Comments

[AustenF3]

When the Bluetooth board and amp are on the same power supply a ground loop occurs creating obnoxious noise. Look into ground loop elimnation if you are working on this project or other Bluetooth audio projects:
https://youtu.be/b2Pb1KuVDS0

[AustenF3]

The included high pass filter with the krc-86b doesn't quite get all the noise. At least with my set up.

[Dm07087]

Good to know, perhaps a different cap value would help

[Dm07087]

I have no such loop in mine. Perhaps there is a bridged joint somewhere in the chipset?

[AustenF3]

I bread boarded out all the components and have discovered digital whine and regular patterned beeping in the audio output. If I connect the amp module to another power supply there is no such impractical sounds. Same if I connect the Bluetooth module to another power supply. Using two batteries isn't really an option. What might I be missing. Did you encounter this? ---- If I had the power for the amp connected through the bluetooth module like you have done, would this solve the problem?

[Dm07087]

The power wires look correct but you have to wire the audio wires from the Bluetooth out to the amp in and from the amp out to the headphones. Also please make sure the capacitor is not backwards or bridged.
I hope this helps.
Danny

[AustenF3]

Thank you! Thank you! I have now made the power for the amp come from soldering to the Bluetooth boards power. And voila! solid sound!

[Dm07087]

Congrats! My pleasure.

[AustenF3]

The krc-86b board I have lacks output in the bass. Overall audio sounds a little hollow. To confirm this I plugged it's output (with use of amplifier ) in to my koss proffesional studio headphones. I compared bluetooth input versus also a audio wired input on the board. The sound was pretty much the same. But no digital noise or hiss (the bluetooth noise is pretty négligeable for regular use, sounds like record player hiss) when using the wired line in on the board. Then I bypassed the board and wired in a connection just to the amplifier and sound was "normal" (solid bass and less hollow). Just a comment. I might try another board for the next head set.

[Dm07087]

I noticed the hollow as well but it works great for classic rock if you like the color they give it. There are better chips and amps out for higher quality cans.

[AustenF3]

Still very good for the pioneer se50s

[VladimirO7]

How long does this battery last?

[AustenF3]

10 to 15 hours based on my use. So you could use a smaller battery and fit everything with more ease in one driver shell. I was able to fit the 500mah one very crammed all other components in one side.

[Dm07087]

I have used it for about an hour and 15 mins straight with no issue. I haven't used it much longer than that.

[AustenF3]

About to undertake this project! So you use the headphone in port for charging? And then added a toggle switch for power?

[Dm07087]

Yes, exactly I hope you enjoy them!

[AustenF3]

Thanks for the reply. How did you secure the "1/8 panel connector" to the driver casing?

[Dm07087]

I purchased a panel mount jack at used a solder pen to make the starter hole, I then used a small file to fit it snug and then used the mounting screw.

[AustenF3]

here is a good take apart guide for the se-50's https://blog.cyplo.net/galleries/PioneerSE50/index.html

[cobourgdave]

Nice and timely instructable. since I want to do something similar. Your project was nicely laid out and easy to follow. Nice job. Many thanks