Why Does This Simple Italian Vintage Synth Sound So Good

I dithered a lot before buying the Elka Solist 505: I had no idea if it would sound any good. It looked odd and rather cool because it has accordionstyle buttons instead of a piano keyboard, which made it interesting enough for me to try. When it arrived in my studio, I was in for a surprise. SOUNDPACKS, MUSIC and LOVE: MY SIGNATURE SOFTWARE: THE HAINPACK IS HERE: GRANULAR SYNTH: MELLOTRON TEST EQUIPMENT INSTRUMENT CHANNEL MEMBERSHIP: MY MUSIC: FASHION: CONNECT: BUY THE GEAR I USE (EU): BUY THE GEAR