You can connect the bluetooth-box to your amplifier with a 3,5 mm jack plug and power it with a 5V power adapter includes a micro-USB-plug. If you use a white or transparent filament, it will glow in blue, if you use, for example, the board below in the link.

You need also a few tiny spax screws, to fix the board in the box and to screw the lid to the box. No soldering is necessary.

Size of the box is width 50 mm, depth 50 mm and height is 30 mm.

When the box is assembled, use e.g. your cellphone to connect to it and play your music as loud as hell.

You can buy the bluetooth board here or here.

Have fun!