Modification: Ausdom M06 Headset to Bluetooth Headphone Adapter

Having recently just reviewed the Ausdom M06, I decided it didn’t quite fit my needs as a headphone, but it had a perfectly adequate and capable Bluetooth chipset. As a result, I decided to embark on a short journey to modify the unit into a Bluetooth headphone adapter, since the only other one I had was a TDK BT-100 with a measily 4-hour battery life, or a generic one that had no bass due to a bad output driver configuration.

Of course, I had noted that it was possible to slave a headphone off the line-in port without actually doing any modifications, but this comes at a disadvantage, since the integrated speakers will be producing sound causing noise, consuming battery and affecting the output impedance which may cause additional distortion. Instead, I was interested in disabling the internal drivers entirely, to have just a bare “adapter” configuration.

This isn’t intended to be a guide on modification, and of course, I will not be held responsible for anything that you do as a result. The first thing I did was, as per the teardown before, take the unit apart.

From there, I started by desoldering all the wires from the side with the battery. Take care when desoldering the top B+ and B- leads not to let them short out, as they are to the battery at the rear. Desoldering all the leads allows you to then remove the PCB, which I decided to save for the microUSB B charging jack.

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A similar process is repeated for the other side, with all the wires desoldered except for the wires to the microphone which we might as well keep.

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Using a small knife, I cut around the driver to break the glue loose and remove the driver. I also scraped the foam away from the front, although that isn’t strictly necessary.

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This helps increase the space between the PCB and the front plastic fascia.

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When removed, we can see the drivers which have a very fine plastic film diaphragm with ribs for added strength and pretty strong magnets. However, the act of putting them on and off over a few days has caused crinkles in the film due to insufficient venting, and that slight damage to the driver can have the effect of reducing the audio quality due to an irregular wavefront and or flexing of the film itself. Anyhow, I won’t be using these anymore.

We can now pull on the earcup joint to release the cup itself. I will be using one cup, namely, the one with the microphone and power button as the body of the unit. The next step is to “reintegrate” charging on this side. I decided to ream out the hole on one side of the earcup to accommodate the microUSB B port. The PCB was cut so as to have the port and a small section, and wires were soldered from the + and – to the 5v and B- terminals respectively. I did an initial test using the connector shield as – but it turned out to be not connected, so … hence the plan B by scratching away some solder resist.

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A decent amount of super-glue was used to hold this in place at the rear, and its profile is so low as not to interfere with the rest of the PCB. It sits a little deep, but the stock cable mounts perfectly with the socket inside.

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The PCB was then restored to its position, and the battery affixed to the rear and leads soldered to the B+ and B- connections.

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It all fits pretty well, and as noted before, the Line-In jack actually serves perfectly as the Line-Out so I didn’t have to supply my own jack and find a place to mount it. Of course, now this has no AVRCP button connection, so we lose the Play/Next/Previous buttons, but I really had no use for them anyway. The important buttons – power, volume are all on this side, so that’s fine.

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It’s a simple matter of reassembling the cup, plugging in your own headphones and for added effect, I decided to restore the ear cushion just to make it look a little nicer.

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A perfectly functional, albeit chunky, long-lived Bluetooth headphone adapter. Additionally, you can thread a cord around the holes and dangle it around your neck like a pendant to make it completely mobile and hands-free.

About lui_gough

I’m a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!

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