Audio speakers (standard ones) have not changed, it's still a speaker output. Would help if you listed what exact amplifier you are using, but the outputs on it should be the same as on a 30 yr old amp, basic L/R/Ground cables.
Connecting older speakers to newer amplifiers and receivers is quite simple and intuitive. In fact, advances in speaker adjustments in modern surround receivers make compatibility even more likely, making vintage speakers easier to integrate with modern gear. Strip off any old speaker wire that may be green or brown with corrosion PointClick Care CNA