Just received a small envelope with two tubes of IC's, Beiling Shanghai BL3101 and BL3207, admitted clones of the Matsushita MN3101 and MN3207. They're, respectively, clock generators and bucket brigade delays for analog signals, used together to create an analog delay, most often today with some clock LFO modulation causing Doppler distortion effects known as "flanger" and "chorus" to the musicians. There is an abundance of borderline cargo cult level "knowledge" on these effects among the "circuit benders", but also in this flood of misunderstandings, cause/effect mixups, beliefs and folklore there can be found solid engineering tips. Currently sorting through all those sources trying to decide which circuit to start with.
This is a winter evening project with the Middle Boy.