The goal was to reduce the amount of cables needed. The Raspberry Pis with the Amp+ boards need a 12-18 V power source, so I chose a large 12 V / 30 A regulated power supply to power the 7 Raspberry Pis.
Connected to 220 V mains voltage, the output delivers stable 12 V, perfect for our audio system.
I then built tiny “splitters” of 1 mm² cables and quick connectors. I used 4 of these, since I didn’t find connectors that held at least 8 wires.
It’s fast and easy. I connected these tiny splitters to the power source’s output, where 2 of the 3 outputs are now used.