Capacitor size, does it make much difference?

I just bought a brand new, still in box 2009-10 Sony STR-DA5400es AV Receiver for $150, the receiver sounds great. But when looking through it's service manual, I noticed that the 2 main power caps are kind of small, they are only 8600uf each, that seems kinda small for an AV receiver that originally retailed for $2000. Why would Sony use such small power caps, and does it really make much difference?

 

The size of the main reservoir caps isn't very important, it depends on how the circuit is arranged, whether earlier stages have the supply stabilised, and what the power supply rejection ratio is for the various stages, especially the output.

As long as the distortion and noise at full output is adequate, then it's adequate.

The main thing larger caps gives is the ability to hold up full power above the continuous rating, the old 'music power' rating. Bigger caps will hold up longer under peak conditions, and give more dynamic headroom. The downside of bigger caps is a larger switch-on current surge, requiring a higher current rating on the rectifier and mains transformer and thus adding to cost and/or reducing reliability.

As with most things, it's a compromise, and anyway, 8600uF isn't a particularly small value, so it's not anything I'd be concerned about.

S