Need understanding on amperage

Seriously? You better believe it. Real life sounds have sharp, high transient peaks that seem like no big deal but require massive power to faithfully duplicate in a sound reproduction system. The amplifier has to generate sufficient power to overcome the mechanical and electrical inertia of the speaker drivers to make the slap of a drum or pluck of a string sound real. The more power on tap in the amp, the more realistic the sound. That's why amplifiers have big transformers and capacitors, so they can hit those momentary high Wattage peaks if just for 10 ms or so. Not 14,000 Watts probably, but 3000 Watts is possible for a very short time. That power is needed to make the fast rise times so the music doesn't sound blurred or distorted. That's the difference between listening to a hifi system and a clock radio. For sure, the transistors will pop like fuses if they have high current levels for too long. It is all about heat buildup inside the semi-conductors. His amp manufacturer rates the transistors for 60 amps, but no idea if that is for 1ms or 1 hour. The circuits may be capable of those power levels, as I am thinking for robustness, but agreed the amp could never generate those power levels for more than milliseconds (and likely not 60 amps) being supplied by a standard 120VAC wall plug.
One example that comes to mind is the 1812 Overture. I have never heard the cannons faithfully reproduced by a stereo system. The power to do it would be at the industrial level, as well as the speakers to handle that sound pressure level. I mean you know they are cannons that are being fired, but not even close to the impact and shear power of the real cannon shot. I think it would be fun to play the record and have someone fire real cannons at the appropriate moments, but the neighbors might not think it so much fun.

Tonywinsc, that music has such transients and that a stereo needs either very high power and/or efficient speakers to reproduce those transients is not a matter of debate.

What is a matter of debate is the math. Its more than just the current rating of the output devices; if you are really drawing 60 amps from the output section its pretty safe to say that the power supply voltage will be near zero as the amplifier is not capable of 14,000 watts (4 ohms) or 3600 into one ohm. In fact in this case the specs show that from 8 ohms to 4 this amp does not double its power, so we can see that there is a current limit somewhere (likely the power transformer). So the 60 amps will not be coming through the speaker terminals. Its a measure of the storage in the supply and when you look at the brochures this is confirmed. Its got a lot of storage, 100,000 uf. That is all the 60 amp figure is stating.

We make a tube amp that can do the same thing. In fact its rated at 80 amps because it has more storage than this transistor amp does! But in both cases all that current is not available to the speaker, if it were such amps would have a bad reputation with speaker manufacturers :)

The extra energy storage does however help with authority and smoother delivery at high power levels as there is less noise in the power supplies and so less intermodulation distortion. But it has no bearing at all on the amp's ability to drive 'difficult' loads. If you look at inexpensive SS amps of similar power, they have similar specs and ability to drive difficult loads; the difference is they likely don't sound as good doing it. **That** is the difference between the men and the boys, and why we pay the extra dollars.

Agreed. I know nothing of his specific amp other than they rated the transistors at 60 amps. No speaker could handle that level of amperage without blowing fuses, crossovers or drivers.
That is cool about your tube amps. I agree, there is no substitute for iron and copper. One nice feature about tube amps with transformer outputs- you can't blow them by shorting the outputs. Transistor amps are not so robust regardless of their current rating. I don't know how much protection today's SS amps, or my SS amp for that matter, have built in to guard against shorting. I'm certainly not willing to test my amp. But I know a few decades ago that one of our LVDT suppliers used to use audio tube amps for testing them and never had issues. When they updated to SS amps, even the briefest shorting of the output leads would pop the transistors. They had to redesign their test stations so the production operators couldn't short the amps.

From the A21 schematic published by Parasound, each power buss to the output stage is fused to 8 amps. No amplifier fused for 8 amps will run 60 amps very long before vaporizing the fuse link.

From the Littlefuse data sheets for an 8 amp fast blow fuse, 60 amps blows the fuse in about 10 milliseconds. Each channel has 50,000 mfds of capacitance, and left and right channels have separate power supplies (so the full 100,000 mfds is not applied to a single 60 amp transient, only 50,000 mfds is, and those are further divided to a V+ cap at 25,000 and a V- cap at 25,000 mfd).

If you calculate the drop in voltage of the 25,000 mfd capacitor, I=C*dV/dt, so I=60 amps, C=25,000 mfd, and dt = 10 milliseconds (the time to blow the fuse), we find dV = 24 volts, or about 1/3 of the 80V supply voltage.

So if you shorted this amp, it would deliver 60 amps for the 10 milliseconds needed to burn the fuse, and have plenty of power supply voltage left in the capacitor.

It could potentially drive a 1 ohm load to 60V (or 3600 W) for 10 milliseconds. That's it, and it's limited by the fusing.

Dhl93449, your math looks right but your conclusion doesn't. At the end of 10mS the supply voltage is only 24V so the current would be 24 amps- only 576 watts. The fuse would go a little longer and the 3600 watt figure would go much shorter or am I missing something?