Analog synthesizers can trace their lineage back to the Trautonium and other vacuum-tube and electro-mechanical instruments from the 1920s and 1930s. After the 1960s, analog synthesizers were built using operational amplifier (op-amp) integrated circuits, and low-pass and high-pass filters designed by Moog, Buchla, and other individual experimenters. In the 1970s and 1980s, digital control of analog synthesizers, and ultimately digital synthesizers, began to be released from the likes of Moog, Buchla, Sequential Circuits, Oberheim, Roland, Korg, and Yamaha among others.
These instruments became the vintage “classics” that define the sound of modern synthesis. And while you might think “vintage classic” means analog only, digital synths such as the DX7, Fairlight, D50, M1, Wavestation, and more have made their way into the category as well.
Original instruments are highly sought after today. In many cases, such as the Moog Modular, Sequential Prophets, and Korg MS-20, they have been reissued in various updated forms. And modern software, sampling, and hardware synthesizers often recreate and emulate the sound of those vintage instruments.