Doepfer Musikelektronik GmbH is a manufacturer of audio hardware, mostly synthesizer modules (modular synthesizer), based in Gräfelfing, Germany and founded by Dieter Döpfer. Dieter Döpfer was studying phsics and the mechanical standard was how the dimensions were developed. 19" rack mount was the format – took a catalog from a case manufacturer for scientific equipment and took the document with the drawings and dimensions to create the eurorack format. Bob Moog was a huge inspiration for Dieter and the Moog filter was a pioneer for this. The Doepfer VCO for example was also heavily modeled after the Moog VCO.
In 1996, Doepfer Musikelektronik released the first Eurorack-format modular synthesizer system called the Doepfer A-100, followed by successive new series of compatible modules in 1997 and 1998. By 2013, the Eurorack format had gained in popularity.
The first modular synthesizer was developed by German engineer Harald Bode in the late 1950s. The 1960s saw the introduction of the Moog synthesizer and the Buchla Modular Electronic Music System, created around the same period. The Moog was composed of separate modules which created and shaped sounds, such as envelopes, noise generators, filters, and sequencers, connected by patch cords.
The Japanese company Roland released the Roland System 100 in 1975, followed by the System 700 in 1976 and the System 100m in 1979.
By the 1990s, modular synthesizers had fallen out of favor compared to cheaper, smaller digital and software synthesizers. German engineer Dieter Doepfer believed modular synthesizers could still be useful for creating unique sounds, and created a new, smaller modular system, the Doepfer A-100. This led to a new standard for modular systems, Eurorack; as of 2017, over 100 companies, including Moog and Roland, were developing Eurorack modules.