The technological advances that we've investigated so far have revolved around the vacuum tube. But the invention of the transistor really sparked a whole new era of sound. The advent of small circuits for sound reproduction meant that things could shrink. Tape went into cartridges. Amplifiers used less energy. And everything became more robust.

Old Bossa by Twin Musicom is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/...)
Artist: http://www.twinmusicom.org/