Question about high current amps versus "not high current amps"

Therefore, my conclusion is slew rate is important to SQ, though not as much impedance matching, To the physicists and electrical engineers, is my conclusion valid?

@jsalerno277 No. Its a lot more complicated than that. Slew rate is only one of 40 or 50 variables that make up sound quality. There are some excellent sounding amps that have very low slew rates.

"Low Current" amplifiers (though nobody calls them that) will NOT produce more power into the dips - though in practice they are affected, and will produce some amount that is more or less depending on numerous factors. But they typically will NOT come close to "doubling down". These amps are also called "power sources".

@mulveling This statement is incorrect. You could be referring to a tube amplifier in this. Tube amps, if imbued with enough feedback, can behave as a Voltage source yet won’t double power when presented with a load of half the impedance. Instead, they will cut power in half when presented with a load of double the impedance. If the tube amp has no feedback, then it will behave more like a power source although it will be only roughly so. If the amp has both current and Voltage feedback and the two are balanced to the same amount then the amp can behave as a true power source. If you did this with a solid state amp it would behave that way too.

At any rate, a tube amp with enough feedback can drive a variable impedance test load with minimal variation- around 1/10dB, yet no tube amp is considered ’high current’.

A better model for a ’high current’ amp is one that can double power from 4 Ohms to 2 Ohms. Whether that’s of any help with most speakers is highly dubious; any power amplifier will sound better (have lower distortion) if its not having to work hard for a living!

@thecarpathian 

The capacitance reduces power supply ripple and attempts to feed the amplifier constant DC  voltages. 

Theoretically, the more muscle he has (capacitance), the more weight (low impedance speaker) he can lift with minimal strain.

But I thought when someone was really muscular, they had more ripples? 

Speakers are current driven complex impedance devices. They are not a purely resistive load. Because of that complex impedance speakers require more current at some frequencies tha others.Ohms law applies, but only at a given frequency will the calculations be accurate. 

Amplifiers ability to deliver current to loudspeakers is gated by the current carrying capacity of the output stage transistors or tubes and what the power supply can deliver.. Bigger power supply caps simply give more reserve under demanding loads within the limits of the output devices.

To protect the output stage, some manufacturers implement current limiting that  prevents the amp from trying to deliver more current than the output stage can safely deliver. This happens especially at low frequencies and high volumes, but the audible impacts are throughout the spectrum. 

Power supplies, especially the capacitors, and the output transistors are the most expensive components in an amp. This why 'watts per dollar' is a terrible metric it inevitably leads to amps that measure well on the bench, but donr sound  very good, especially when pushed, or when driving demanding speakers.

Finally speakers generate their own current, called 'back EMF' when a coil moves in a magnetic field. This has to be absorbed and dissipated also by the output stage of the amp, so more load on the output to be accounted for. This also where the output impedance of the amp comes into play, as that determines the damping factor. 

Bottom line, high current amps are in general, a good thing, but not the only thing

@thecarpathian  :  Your confusion inspired me to put this blog post together about the difference between a power supply and the amplifier sections that go into an amp or other device.

Gosh, glad I could help!😄

Off to read it...