Klaus Schulze (for the vowel shift impaired: you pronounce it “Clows Shooltse”) started as the drummer for Tangerine Dream in Berlin, then split off to create his own unique sound as an Analog Synthesizer musician.
Here’s a 1975 album from him. Notable additions to Tangerine Dream-style sequencing are the analog drums – well I should just say, drums, played by Klaus Schulze himself on the studio productions – and the sliding noises from the EMS Synthi, which he and Jean-Michel Jarre used a lot in the 1970ies.
The EMS Synthi is a remarkable synthesizer for its time; British-made; with a central orthogonal switching matrix that would let you mix a number of output signals using resistors you stick into the matrix to produce signal mixes – which would then be fed back into the module system, creating a multitude of possible feedback configurations.
Here is Klaus Schulze demonstrating it.