The Problem My stereo receiver is from the 70s and has a single AUX input. When we have people over, there is no simple way to let people play music without unplugging TV connection, adding an RCA -> 1/8 Stereo cable, and making people plug in directly/leave their phone by the receiver.
Add an intermediary device that people can stream to via Bluetooth, which outputs via RCA to the receiver.
Old HiFi receivers! Hardwood (or veneer) + polished metal.
Electronics Fabrication Process