Amplifier by their physical placement in the signal chain; a preamplifier may precede other signal processing stages, for example. The first practical electrical device which could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Today most amplifiers use transistors. The first practical device that could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912. Vacuum tubes were used in almost all amplifiers until the 1960s–1970s when the transistor, invented in 1947, replaced them. Today, most amplifiers
Bob Adams (electrical engineer) Bob Adams (electrical engineer) Robert Whitlock Adams is a Technical Fellow at Analog Devices, Inc. (ADI) in Wilmington, Massachusetts. His focus is on signal processing and analog-to-digital conversion for professional audio. He is a leader in the development of sigma-delta converters, introducing architectural advances including mismatch shaping, multi-bit quantization, and continuous-time architectures. Adams graduated with a Bachelor of Science in Electrical Engineering from Tufts University in 1976. From 1977 to 1988 he worked for DBX, a professional audio recording company. There, he helped develop the industry's first audio converter with greater than 16-bit resolution, as well as one of the