Cap upgrade?

Joew -

I presume you're asking about a power-supply capacitance increase.

Think of the current coming from the wall as water from a garden hose, and the power supply capacitors as the bucket the hose is pouring into. The bigger the bucket, the more water you have stored up to pour out instantaneouly if you need to.

Increased power supply capacitance gives you greater dynamic headroom and better bass control and extension. It also tends to add an effortlessness to the sound that can improve the sense of ambience and realism. If the speakers that you're planning to drive are an easy load, then a power supply upgrade may not be very cost-effective. But if they're average or difficult, then it makes a lot of sense.

Much of the difference between mid-fi and true high-end amplifiers is in the power supply.

Duke

First-off the capacitors may serve differently and so its upgrades as well. I kinda liked Duke's explaination of the capacitor:-)
PS capacitors upgrade may realy involve chasis cutting or re-structuring since in general audio rules of thum the larger the better.
Applying faster acting caps(fast chartge-discharge) for the PS even with smaller capacitance is much more cost effective EVEN for the easy-load speakers as they introduce far less amount of distortions.

Perfect description. Thanks. I am purchasing an amp that has had the upgrade and I am wondering how that will affect the overall listening experience. But your explanation was just what I was looking for.