AVR- automatic voltage regulators

i just opened up an old tape player, the power supply unit fascinates me. all those capacitors and transformers.
took a really long time staring at that thing, looking at the schematics and figuring out how it works

then i went online to search about AVRs
here's what i found:
 in wikipedia: http://en.wikipedia.org/wiki/Automatic_Voltage_Regulator

a boring video from google ppl: http://www.youtube.com/watch?v=M5wfv7RE_J4&list=QL

then i got a lil carried off
wooh look at how these ppl talk: http://www.youtube.com/watch?v=pK9wsf58a6Q&list=QL&playnext=2

oO amplifier in a tin! http://www.youtube.com/watch?v=pQBAnjq6hKQ&list=QL&playnext=2

match missiles =D http://www.youtube.com/watch?v=ETnk9FYZRHM

utterly weird ... shrinking chip bags: http://www.youtube.com/watch?v=lhA4XCn2liQ&list=QL&playnext=1

there's these ppl from india i think, with Dynamic voltage regulator (DVR)
http://www.youtube.com/watch?v=YTO4us2jV6o&feature=related

in the end
but there are already ppl who sell this stuff: http://powersolutions.com.my/catalog/Automatic-Voltage-Regulators/LYBRA-Single-Phase-Line-Conditioner-02kVA-15kVA/

but i'm still gonna try to build my own AVR one day