Electrolytic caps have a half life of about 20 years- in that time about half of them will have failed. The transistor amp above that is 30 years old has a seriously degraded power supply; despite that the amp still plays although at reduced performance.
Transistors that are mounted on heatsinks face the danger of the heatsink compounds perishing, leaving the transistor unable to transfer all their heat to the heatsink. Its a Good Idea to remount the transistors with fresh materials about once every 15 years or so.
Corrosion and how well parts are sealed will determine how long the other parts in an amp will last but once you've gotten to 30 years or so all bets are off.
Transistors that are mounted on heatsinks face the danger of the heatsink compounds perishing, leaving the transistor unable to transfer all their heat to the heatsink. Its a Good Idea to remount the transistors with fresh materials about once every 15 years or so.
Corrosion and how well parts are sealed will determine how long the other parts in an amp will last but once you've gotten to 30 years or so all bets are off.