This is a solid-state switch used to switch audio between multiple sources. The chip is a CD4052 which is a 4PDT (Four pole double throw) switch that is capable of handling split power supplies. It is slightly easier to implement than the CD4066 chip which could only handle single supplies.
Schematics on my blog for this video: [ Ссылка ]
![](https://i.ytimg.com/vi/93teJFpJiZU/maxresdefault.jpg)