The 1st transistor circuit lions ever used was the emitter follower as the high side of an h-bridge. Never knew the applications or that it was formally a design.

It turns out the emitter follower is a way of eliminating voltage ripple, though very obscure.  Years of goog searches for defeating ripple yielded only RC circuits. Even coworkers with a lot more degrees than lions used only RC networks. Lions used linear regulators right until this video, with very frustrating results. The microphone preamp just accepted very high output ripple in exchange for less headroom. The audio recorders just sacrificed huge amounts of space for giant capacitors.

A lot of circuits can now get a lot smaller. Suspect ADCs which specify 5V & suddenly get very noisy below 5V are all using emitter followers to defeat ripple.