Need understanding on amperage

To clarify: The 60 amps figure of the amplifier is not how much current the amp can produce driving the speaker. If it were, we could apply the power formula, which is that Power equals the current squared times the resistance of the load.

So if we give the amp the benefit of the doubt and use a 1 ohm load, that means that the power output of the amp is 60 amps squared; 3600 watts! Obviously the amp can't do that, what this 60 amp number represents is how much current is produced when the power supplies are shorted out for 10 milliseconds, something that you would never, ever want to do!

So this has little to do with whether the amp can make a lot of 'current' when driving low impedance loads. I know of several tube amps that don't make nearly the same power than tout the same figure.

To further clarify.

When you look at a "current rating" spec you need to know at least two things:

(1) At what voltage is the current being specified.

(2) Is the rating CONTINUOUS or transient.

The ratings on wall power are usually continuous maximums (in root mean square or RMS) and are at your line voltage of 120 V AC.

The 60 amp rating for a power amp like the Parasound are TRANSIENT, good for only a very short time and at a voltage much lower than your line power levels.

Make no mistake, if that A21 tried to output 60 amps for more than a few milliseconds, fuses would blow.

In the old days, manufacturers were required to avoid transient power/voltage/current specs because they can be so misleading for consumers. Only RMS continuous specs were allowed to be published.

Watts = Volts * Amps

Never heard of an amplifier rated in "amps per channel" before.

the 60 amps is stated under "current capacity" under the specifications section on their website.

Like a few have already stated, power is a better way to look at the system because power is constant even when current and voltage are changing. What that means is that the amplifier has transformers to reduce the voltage levels. So current out of your amp can be higher than the current at the wall since the voltage is lower. Your amplifier spec is stating 60 amps to either show a short term power storage peak output or else to say that the transisitors are robust enough to withstand that current draw for some period of time without popping.
A 120 VAC wall plug can safely handle about 1200 Watts. Looking at high power home appliances, I doubt you could find a microwave oven or toaster rated higher than that. I searched far and wide for a 2-slot toaster rated at 1200 Watts so I can have decent toast. Anyway, 1200 Watts is a 10 amp load and anyone with an older home will tell you, don't try to run a microwave oven and a toaster on the same circuit at the same time. So like someone already said, if you were to input 60 amps into a 1 ohm speaker load, that would be 3600 Watts. It may be possible for some milliseconds with the help of the energy storage capacity in your amp, but not continuously simply because a house circuit could not handle that load.
My amp pulls about 5 amps all the time out of the power conditioner. I have seen it peak at 5.7 amps if I have the music cranked. My voltage hangs in there at around 122 VAC because I have a dedicated circuit. So I am pulling up to 700 Watts total- but only for a second or two. The amp output would be something less than 350 Watts per channel. Then my wife tells me to turn it down and my current draw is back to 5 amps. If my speakers have say a 4 ohm average load, then the current draw into each speaker is no more than 9 amps. That is 18 amps total, even though the current draw at wall is only 5.7 amps. These are rough examples because the power output to the speakers will be a little less than the power into the amp due to losses through the amp (in the form of heat).