Music technology (electric) remained so until the 1920s, when several recent radio-related developments in electronics converged to revolutionize the recording process. These included improved microphones and auxiliary devices such as electronic filters, all dependent on electronic amplification to be of practical use in recording. In 1906, Lee De Forest invented the "Audion" triode vacuum tube, an electronic valve that could amplify weak electrical signals. By 1915, it was in use in long-distance telephone circuits that made conversations between New York and San Francisco practical. Refined versions of this tube were the basis of all electronic sound systems until the commercial introduction of the
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