Revive a Bose SoundDock 10 With Bluetooth

After completing my project to restore several Bose Series I SoundDocks by adding built-in Bluetooth, I decided to do the same thing with a SoundDock 10 that has also been gathering dust. This SoundDock is a little different because in addition to the 30-pin dock for iPods/iPhones, it also includes an auxillary input, so I thought that adding Bluetooth might be as easy as connecting the audio out from the Bluetooth module in parallel with the pins of the auxillary input jack. However, the SoundDock 10 can't be switched to Aux mode if there's no cable plugged in, but a quick continuity check of the Aux jack indicated that I could emulate this by connecting the two "switch" pins together on the circuit board.

To power the Bluetooth module (I used a different module for this one, with Bluetooth 5.0 support), I knew that there should be a 5-volt supply available because the SoundDock 10 follows the more recent 30-pin dock specification that supplies 5 volt charging power to the iPod. I confirmed this by finding the voltage regulators on the controller board of the SoundDock and checking their output. I then found a solder pad with the same voltage to which I could attach the power wire for the Bluetooth module. With the audio in and power sorted out, I was all set to wire in a HM-M28 Bluetooth module to see how things worked.

Once wired, the Bluetooth module worked fine and sounded good until I raised the volume of the SoundDock beyond the first couple of settings. The interference noise that's common with the little plug-in adapters was present, but from my research on resurrecting my other SoundDocks, I knew what the problem was and how to fix it. By using the Aux in for my audio path, I did not have an isolated audio ground, and since the Bluetooth module was powered by the SoundDock, this created a ground loop that introduced the noise. To resolve it, I needed to add a DC-DC isolation converter. As the name implies, an isolation converter effectively separates the power supply of the Bluetooth module from that of the SoundDock, eliminating the noise-inducing ground loop. I found a pair of 5 volt isolation converters on Amazon for $7 and added one between the 5 volt power from the SoundDock and the Bluetooth module, and the noise was eliminated.

Fitting the Bluetooth module and the DC-DC isolation converter in the SoundDock 10 was also easy. Once you remove the docking circuit board and the docking controller board that sits beneath it, there's ample room in the now-vacant docking recess to mount the new components. All it needed to finish the job was a flat wood or plastic cover to hide and protect the new components (so no 3D printing required). I originally planned to add a switch so I could turn the Bluetooth module off when I wasn't using it, but was pleasantly surprised to find that the SoundDock has a sleep mode that cuts the 5 volt power automatically after a period of no activity, so no switch is required. One thing to note about the auto-shut off feature is that the SoundDock will enter the sleep mode if the input level is too low, so you need to have the volume of your phone or other Bluetooth source device at at least 50% volume level, and then use the SoundDock volume to adjust the volume from there.

If you have a SoundDock 10 that works but you don't have a 30-pin iPod or iPhone, you'll need the following to bring it back to life by adding a built-in Bluetooth module.

• Bluetooth 5.0 Audio Module (two for $4 on Amazon)
• B0505S DC-DC Isolation power converter (two for $7.50 on Amazon)
• 30-AWG Silicone Insulated Wire (7-spool set for $14 on Amazon)

You'll also need a small piece of 1/8" or so thick black plastic to cover the components mounted in the 30-pin docking bay. I used a scrap of cherry from my woodworking shop.

I should also note that the SoundDock 10 needs a remote to function, but if yours has gone missing (as mine has twice now) you can buy replacements on Amazon or eBay.

Tools

To complete the wiring, you'll need a fine-tipped soldering iron with solder and flux, a cross-point screwdriver, and a wire stripper capable of stripping 30 AWG wire. To mount your components and finish everything off nicely, you'll need a coping or jig saw to cut the plastic along with some sandpaper to adjust the fit, a drill to make a small hole for the Bluetooth LED (if you even want it to be visible), and a hot melt glue gun to fasten everything in place.

Since this modification eliminates the need for the obsolete docking connector and uses the empty cavity to house the new components, you have to remove the 30-pin connector board and the controller board that sits beneath it. Here's how you do that.

1. With the SoundDock upside down, remove the five screws on the bottom of the SoundDock, as indicated in the picture above.
2. Gently pull the ribbon cable free from its connection inside the SoundDock.
3. With the docking shelf free from the SoundDock, turn it upside down and lift the metal clip holding the controller board to free the circuit board.
4. Continue to pry the metal clip up and to the side to completely remove it from the plastic docking housing.
5. Remove the docking circuit board and the plastic holder for the docking circuit board.

At this point the docking shelf is free of the unwanted components and ready for the new Bluetooth module and DC-DC isolation converter.

You'll need to have access to the DSP controller board on the SoundDock so you can solder the three audio input wires and two 5-volt power wires. To access this, remove the three larger screws from the bottom of the SoundDock and pull the bottom cover straight up.

It's easiest to start by soldering your wires the Bluetooth module and DC-DC converter. I encourage you to use silicone insulated wire and to follow my color scheme, as it will make it easier to solder the wires to the circuit board in the next step.

• 8" yellow: left audio in
• 8" red: right audio in
• 8" green: audio ground
• 4" black: power ground
• 4" red: 5 volt power
• 1-1/2" red: 5 volt power DC-DC converter to Bluetooth module
• 1-1/2" black: ground wire between DC-DC converter to Bluetooth module

Strip about 1/16" from one end and 1/8" from the other (the audio ground and 1-1/2" lengths should be stripped to 1/8" on both ends). Solder the 1/8" end to the Bluetooth module and DC-DC converter following the pictures above. I wanted to locate the DC-DC converter in the cavity on the bottom of the docking shelf, so I threaded the wires through the opening before connecting the DC-DC converter to the Bluetooth board.

After you've attached all of the wires to the module and the converter, thread the wires through the docking shelf as shown, and with the SoundDock upside down, set the docking shelf on the bottom of the SoundDock so you can connect the wires to the circuit board on the SoundDock.

Follow the photos above to solder your wires to DSP controller board. Note that the audio ground wire connects two of the pins on the Aux input jack. This is what enables the Aux mode on the SoundDock even when a cable is not plugged in.

With everything wired together, it's time to test things out. Plug your SoundDock into AC power. After a few seconds, the LED on the Bluetooth module should start to blink rapidly. Your SoundDock is still in standby mode at this point, so you'll need to activate the Aux mode by pressing the Aux button on your remote. If you've done everything right, the Aux light on your SoundDock will stay lit and you're ready to connect a Bluetooth music source and start streaming to your SoundDock.

To pair the Bluetooth module, go to the Bluetooth settings on your device and connect to the "BT5.0-Audio" item (you can change the display name through your device's settings options if you choose to). You'll hear a confirmation "bluetooth connected" through the SoundDock, and should be able to start streaming audio. If this doesn't work as descibed above, first make sure that your remote is working. You should see the Aux light at least flash when you press the button on the remote. If that's working as expected but you're not hearing any sound when you're streaming audio, increase the volume on your SoundDock and on your device. If you still don't hear anything, it's time to go back and double-check your wiring. Start with the external components before you open your SoundDock back up.

If everything is good, you can fasten the DC-DC converter in place in the underside of the docking shelf before re-assembling your SoundDock. I secured mine with a dab of hotmelt glue. You can now put your SoundDock back together. Start by placing the bottom panel on the SoundDock and re-attach the plastic docking shelf, taking care to ensure that the wires are routed through the slot where the ribbon cable previously was. With the docking shelf in place, you can then fasten the bottom panel with the 3 larger screws.

You're now ready to secure the Bluetooth module in place and add a cover over the docking recess to keep them safe. If you want to show off your handy work, you could opt for a piece of clear plastic. I used a piece of 1/4" thick cherry wood and also cut a slot n the shape of the remote to create a little cradle for it.

To make the cover, use the original docking bay as a template. Then use a coping saw or jigsaw to cut the cover to size, and sand the edges as needed to get a good fit. If you want to be able to see the Bluetooth module LED through the cover, you'll need to drill a small hole above the LED on the Bluetooth module. I also filled the LED hole with clear hot melt glue to create a nice lens for the light.

When your cover is ready, position the Bluetooth module in the cavity and secure it in place with a dab of hot melt glue. Once the glue has set, use a few dabs of glue to secure the cover in place (don't get carried away in case you need to re-open the cover).

That's it. You've now brought your SoundDock 10 back to life and made it usable with any device that provides Bluetooth audio. This modification preserves the functionaliy of the Aux in jack, so you can still connect a non-Bluetooth audio source. The latter feature is also handy if you want to use your SoundDock for watching movies, because it gives you 100% lag-free audio. The Bluetooth module I used is pretty good in terms of lag and I've found that it's tolerable for watching movies, but a hard-wired connection is still best for this purpose.