Big caps v Little caps

I'm not an EE guy, so its ok to talk down to me. I'm just curious. I've noticed 'older' amps (Robertson Audio Forty-Ten) and certain brands (eg Hafler) and 'unusual" brands (Pathos) use just a couple of giant capacitors, while most of the mainstream equipment I see, seem to use lots of smaller caps.
I bet someone can explain this to satisfy my curiosity?