I throw out my ac a few years ago, and now i wanna try my old 2600 again ^^ so howe much V? (if anyone here knows)

Google is your friend!

http://www.tomheroes.com/Video%20Games%20FS/video%20games/Atari/Atari%20FAQ.htm

“2600 power supply: —————— Input: 120VAC 60Hz Output: 9VDC 500mA Polarity: Center +, Outer -“

Thanks! 🙂