modular synthesizer (this is the case)

In order to build a modular synthesizer, you will need a box to put it in.

So here it is. It’s a Eurorack case and it has a handy (read: necessary) powersupply inside with +12, -12, and +5 volts DC.

This is on the road to becoming an HD Analogue Video/Audio synthesizer

for electronics beginners, this should be a good place to start:
https://syntherjack.net/how-to-start-synth-diy/