Capacitor Size

I know that the capacitors he used were not particularly expensive/ high end, as he stated that they would still be an improvement over the old ones.

I've physically tried to look at the capacitors' specs, but can't read what it says on the cap b/c of the way they are mounted.

I'm going to try to dig up the old paperwork to see if that tells me anything.

How does the amp SOUND?

It actually sounds good, to be fair. But the fact is, I didn't have it in my possession w/ the original caps long enough to be able to notice a significant difference. Further, my speakers are very limited in the lower frequencies, so any improvement there is impossible to judge.

I actually don't have any complaints about the sound, save for the fact that a high frequency problem has arisen, which means the amp will need to be serviced (the right channel emits a lot of spitty hiss, for lack of a better way of putting it, while there is no source playing. I assume it's a capacitor problem of sorts).

Maybe when it goes in for service, I'll ask the tech to have a look-see for me.

Incidentally, despite the original tech informing me that the new caps are physically smaller, I only recently looked under the hood, as a result of the right channel, upper frequency issues (wanted to see if i could spot anything obvious). I was pretty surprised to see just how MUCH smaller the new caps are, however, which is what raised the question in my mind in the first place.

Are you asking about power supply aluminum electrolytic caps or film capacitors???

Your technician was on the level. Its a general rule of thumb that electrolytic capacitors (the kind found in power supplies) decrease in size in newer versions. It was that way in the 1970s and is still true today.