- bass amplifiers
- solid state amplifiers
The Electronic Music Corporation (EMC) of Cleveland, Ohio made guitar and PA amplifiers, as well as sound system consoles and speaker cabinets. From 1968 onwards EMC used transistors in their amplifiers instead of vacuum tubes - so these were solid-state amplifiers. In 1969 EMC introduced the first plug-in power module - if these failed then they could be easily swapped out by anyone with a screwdriver. Three interchangeable modules covered the 51 EMC amp models.
Source: EMC catalogs 1971 - 1974