DIY Bluetooth Modification Sony MDR-7506 Headphone

This post about convert famous headphone Sony MDR-7506 and its fake copies to DIY Bluetooth modification.

I had headphone Sony MDR with very great sound and comfortable design. And also quite thick cable is with it. That was well when I used one on my office. Use it during walk to home or job difficult, because cable dangle, pulled down, tangled in clothing. That actually annoyed me. Therefore, I decided to detach cable and convert headphone to Bluetooth version.

Currently there are many BT modules fit for sound DIY project. Some of ones support APT-X. I chose stereo CSR8645 module with amplifier board. Module also support microphone and I add this feature to MDR BT mod.

Step 1: Parts

Here is part list:

- Bluetooth 4.0 CSR8645 module with amplifier board

- Charge LiPo battery module TP4056

- LiPo battery LP602030 overall dimensions 6х20х30 mm

- microphone ECM-10C diameter 6 mm

- tact push button high 9.5 mm (KLS7-TS6601-9.5-180) – 5 pieces

- mini slide switch appropriated size

- some tools and materials…

Step 2: Modelling

First I disassembled left and right ear cups and measure inside dimensions, then each of ones was created 3d models. Also I did it for other parts of set. Then I spent some time try to assemble and after few attempts I had acceptable result. All models you can find here – https://grabcad.com/delirium-1/models

I developed two kind of circuit board for right and left ear cup to place parts. Bluetooth module with buttons are soldered on custom circuit board and putting in left ear cup. Before it i drill holes for buttons and extended former hole for cable until diameter 6.5 mm then inserted microphone in it then soldered to circuit board too.

Charge module TP4056 and slide switch are placed on circuit board inside right ear cup. There is LiPo battery there too. Also i must cut two slot on a side ear cup. One for switch and another for micro usb charged cable. Dimensions right circuit board is on picture (previous design board with sensor switch, but it has same size as new).

Step 3: Make Circuit Boards

Then I made circuit boards.I used male pin header to solder parts on boards and

then cropped they a little to make "sandwich" less thick.

Here is ready Bluetooth board assembly.

Step 4: Test and Mount

First time test.. great, it’s working! Module pair to phone easily and sounds well. Assembly boards is ready to placed into ear cups. I used melt plastic gun to fix they.

Step 5: Finish

At the end, I replaced original cable (two wires) between earpiece by usb cable (four wires) to connect sound and power line. I obtained quite similar on previous result. DIY BT mod MDR-7506 headset done.

Left ear cup. I drilled hole diameter 1.5 mm for amplifier red led that indicate work headset, and dripped a little melt plastic.

Right ear cup. Red led is bright if charge on. When charge full blue led is bright.

Step 6: Result

Here is view on microphone and buttons. Unfortunately,

I worked dremel carelessly… However, that doesn't matter, because ultimate result is pretty well.

Step 7: The End

Thanks for your attention!

And warning! If you want to make same with you Sony MDR-7506 you will most definitely void any warranty you might have for your headphones. You might also damage your headphones if you are not careful, so please do not accuse me!

If you need more information such as electrical schemes, print circuit boards, some explanations, etc, contact me.