Not so fast, Grasshopper. The main reason for high capacitance storage banks is not buffering, it's for ripple free DC. The added power reserve thus gained is nice, but is not the main reason for doing do. As for the supply voltage, the only difference between using 220 or 110 is the number of windings in the transformer primary. Yes, if both mains have the same current rating then the 220v line has the potential to deliver twice the power, but it's the transformer VA rating that limits the power available to the power rails.
Not so fast, Grasshopper.
"Ripple free DC" is the SAME THING as more energy storage.
In fact, more energy storage is the REASON the DC is "ripple free".
The "ripple" is the decrease of voltage as energy is drained from the capacitor during the large portion of each AC "cycle" during which NO energy is being transferred into the power supply from the mains. It is dependent on the current being drawn from the power supply, so deficiency shows up most at high power.
Thus, a weak set of capacitors will cause the amp to have a perceived lack of low end. The lowest frequencies act almost like a DC drain, since they extend over more than one AC mains cycle.
Because the supply voltage drops appreciably DURING one cycle of a low frequency, the low end will seem "soft", lacking in definition, weak, etc.
As for the higher voltage, there is a point that the poster is correct about. A sudden drain on the mains causes a voltage drop in the mains due to current flow, and thus a corresponding drop of power supply voltage, similar to the "ripple" drop.
With a higher voltage, a given amount of voltage drop is less significant. The traditional UK "ring" type of circuit is quite 'stiff" and has a much smaller voltage drop when compared to continental or US circuits. Even the continental voltages and circuits offer some of that advantage.
Anyone who has operated a table saw run on 110 vs 220V has likely noticed the lack of "bogging down" when operated on 220V. A similar effect occurs with amplifiers, although not quite as pronounced.
So indeed there IS a small advantage to the higher voltage, and it shows up MOST at higher power.
BTW, a transformer's VA rating is "nominal", a long-term rating. Most will provide considerably more power for short periods. Heating is the limiting factor, along with voltage drop due to added currents.
This is NOT necessarily true of an SMPS, which DOES have a "hard" current limit. An SMPS may be over-designed, rated for enough extra capability to "cover" high power peaks, or it may be designed for average power levels only. The latter, of course, is cheaper, relying on capacitors to supply peak power.
(edited to change "frop" to "drop".......)
