A 500W amp is probably a class A and can't really be made more efficient. It would still be 500W in 2024. Decades ago there were more efficient setups too, thou

A 500W amp is probably a class A and can't really be made more efficient. It would still be 500W in 2024. Decades ago there were more efficient setups too, though of course now they sound better and also have lots more features and connectivity.