Electro-Harmonix is an American company founded by Mike Matthews in 1968 to produce effects pedals for electric guitar and bass. Located in New York City, Electro-Harmonix became an early pioneer in effects pedal design and developed multiple affordable and influential models throughout the late 1960s and 1970s, including the Big Muff fuzz, Small Stone phaser, Memory Man delay, and Electric Mistress flanger. Notable users have included Jimi Hendrix, Carlos Santana, Adrian Belew, Steve Howe, Jimmy Page, and Andy Summers. EHX closed in 1984 due to financial struggles, with Matthews founding the New Sensor Corporation to pursue business ventures in Russia under the brand name Sovtek. Sovtek's success selling vacuum tubes for guitar amplifiers and audio systems allowed Matthews to recover the Electro-Harmonix brand from bankruptcy, and throughout the 1990s Sovtek manufactured Electro-Harmonix pedals in Russia. Production returned to the United States in 2000, with the brand releasing both new models and reissues of many of its classic designs.