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
William Bryson (electrical engineer) had offices at 16 Queen Charlotte Street in Leith. He died on 9 July 1906. He is buried in Warriston Cemetery. The grave lies on the diagonal path joining the lower vaults to the sealed eastern entrance. The stone is currently (2018) vandalised and is lying on the ground in undergrowth. William Bryson (electrical engineer) William Alexander Bryson FRSE (2 March 1855 – 9 July 1906), was a Scottish electrical engineer. He was born on 2 March 1855, the son of Alexander Bryson and Elizabeth W. Gillespie. His grandfather was Robert Bryson. His mother died shortly after he was born,