Synthesist Ian Nieman shared this overview and demo of his ARP 2500 Concert Wing – a portable modular synth system, originally released in the early ’70s.

Of particular note is the rare Module 1045 Voltage Controlled Voice – which is essentially a complete basic synth in a single module. The 1045 has a VCO, a low pass VCF, a VCA & two envelope generators, so it can be used as a complete synth voice.