Once my new Bluetooth module came in (same model as before but different seller), I was ready to make the speaker wireless. First, I verified that the Bluetooth module did indeed work. Next, I cut up the line-in cable and soldered it to my amplifier board. Unfortunately, the wires were very thin and hard to work with.

Then I took the case and the USB shield off the Bluetooth module like [Tony] did, and I soldered power and ground leads onto the USB connector for the amplifier board.

I cut up a very short USB cable that I got from BoilerMake this fall so I could use it to power both boards. I soldered power and ground from the USB cable to the USB connector on the Bluetooth module. That way, I could use a USB battery pack to power it.

I soldered the final leads onto the amplifier board, hooked it up to the speaker, and...

Nothing.

I tested each component before soldering everything, and it all worked. After lots of frustration, I determined that the amplifier board died. I must have let the soldering iron on it for too long. At least the audio works, if quietly, as long as I bypass the amplifier.

I'm probably going to end up buying another amplifier board and have a go at it again. But for now, at least, it works.