A vocational school is a start but mostly will focus on digital, wireless, etc. That is were the jobs are. They will also have heating and a/c related classes.
I attended a CC and took electrical technology right out of HS, then I transfered to engineering to get a BSEE degree. The community college electronics technology program will teach circuit theory and analysis, electronics, a big dose of digital circuits, processors/ computers, and rf wireless telecom. Maybe the bigger and better schools will get into power and transmission lines and even basic control systems. They take 2 full years to complete, including college algebra/trig and some basic calculus. They also require Physics and some mechanical tech and computer programming classes. In the end you will learn a lot but the stuff you really need to know to be a bench tech that repairs vintage audio is intermixed deep in all the other course work. The soldering and bench skills are learned in labs and during hands on projects.
I used to teach part time night school at a CC. We used to teach electronics courses that started with diodes and transistors. Most of the circuits you see in a vintage audio receiver would have been covered to some level over several classes. Today the focus is digital, telecom, and a block diagram level of understanding. We live in a throw away world and repair is modular more than component level.
Sorry for the ramble.