I was given a dead Bose SoundDock, so I decided to upgrade it and give it Bluetooth capability. A relatively easy upgrade.

Supplies

Bluetooth 100W + 100W Amplifier with Treble and Bass Control, 9 to 24V, BT and Aux inputs (Amazon, $23.99)

Torx screwdriver, Phillips screwdriver.

1/8" 3 conductor phone plug.

soldering iron.

drill bits, drill.

Step 1: Strip the Bose SoundDock (series 2) and Replace Amplifier

Remove the 4 screws holding the base on. The screws are underneath the rubber feet that are just stuck on over the screws. Remove the fancy grill by gently pulling the grill sides out from under the plastic housing. Then remove all the screws holding the large metal front to the plastic speaker case, including the screws holding the speakers in place. Remove the speaker connectors from the amp board, and put the speakers in a safe place temporarily. Remove the 3 electronic boards held down with Torx screws. Snip off the long ribbon cable (with the one red edge) near the board. Separate the ribbon cable into individual wires, which should be connected to the amp board power in and to a 1/8" 3 conductor phone plug. See image. I soldered the + and - wires directly to the amp board, but you can also use the included power plug and solder the ribbon cable wires to that. The wires with the x aren't used, but the red wire could be used to indicate whether the unit is using the battery or is plugged in via the power adapter. Not really needed.

Drill 3 holes for the knobs into the top of the Bose. Drilling requires precision, mark carefully. The drill must go through 2 layers of plastic, and will extend through the top of the baffle chamber. I removed the nuts and washers of the amp so the knob shafts will extend up a little higher. The amp lays flat against the enclosure. The knobs themselves should fit through the holes. The knobs will be recessed into the case when finished. Secure the amp board to the housing with several layers of thick double sided mounting tape (mine was 1.5 inches wide tape, 2 layers was about 3/16" thick).

Test the unit by plugging in the power supply and Aux input with a sound source. Turn on the power (combined with the volume control). If it sounds good, test the Bluetooth via your phone. Scan for the new Bluetooth device, it will connect without a password. Then download the sound app(s) to the phone, and start music playing through Bluetooth.

Reassemble, in the order it was disassembled.

Step 2: Conclusion

The Bluetooth amp module was an inexpensive way to both fix a defective Bose amplifier and simultaneously add Bluetooth. It sounds good. The nice part is it retains the Li-ion battery system of the original, so is still portable. The battery charger part is included with the battery, so no internal changes are needed, it just charges with the stock 20 volt power adapter. The power output is of course not 100 watts per channel like the specifications say, but neither was the original amp. My guess is it is 30 watts per channel. I can't hear any distortion.