Sunday Synth Jam: This video, via retrosound72, captures a performance of Rainy Days, a vintage synthesizer track by RetroSound (Marko Ettlich)

Technical details below.

All sounds (self-programmed): KORG Polysix (1982)

Arpeggiator used for the line and the internal effects Ensemble and Chorus.
Recording: multi-track without midi
FX: a little bit delay and reverb