I turned the AUX IN jack on my Katana wireless and I thought I write about it because I enjoy doing these mods. It is almost therapeutic to me.
I started with a cheap Bluetooth receiver module intended for cars. My unit had a female jack and an adapter that had male jacks on both ends.
If you get something similar, I recommend you to use a cable instead of the adapter, since that will make the whole thing too rigid, and every mechanical impact to the adapter will be transferred to the AUX IN jack. You don’t want that. A cable makes the connection flexible and much less prone to cause damage.
You can use any 3.5mm TRS cable, or make one.
I made my own because I like my cables to be neat.
Here are some progress pictures of me making the cable
I used some 3M mounting pads to mount the Bluetooth receiver to the back of my amplifier. It stays there secure, but it’s still ease to remove should I have to do that.