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

I’ve always thought the higher the capacitance reserve an amplifier has, the more amps it can deliver when needed. This isn’t correct?

@thecarpathian - kind of sort of. Think of the amplifier as a weight lifter, and the power supply as the stage the athlete stands on. The better the power supply, the stiffer the stand and the better the weight lifter is able to dead lift up to the same point.

The capacitance reduces power supply ripple and attempts to feed the amplifier constant DC  voltages. That is, how much the DC rails vary based on incoming AC and amplifier demand.

Many things go into what the ideal capacitance levels are. Amplifier feedback, speaker load, etc. Generally speaking though, if you want to design a high current amplifier you will need to add more capacitance to ensure it can perform to spec even during high demand.

Should also point out that most amplifiers use linear, unregulated supplies, meaning they are subject to the long term voltage stability coming out of your wall.  Seasons, your neighbors, your HVAC and refrigerator can cause instability even with dedicated lines. 

@erik_squires ,

To your weight lifter analogy;

I would liken the weight lifter to the amplifier, the weight he's lifting to the speakers, and the power supply to how much muscle (power reserves) he has.

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

Is this reasonable? I hope so, because now I need an aspirin...

You have brought me back 47 years to college physics with Herr Professor Doctor Weber at Fordham University.  I want to thank all of the physicists in the thread for excellent, simplified explanations.  Parallel to the OP’s question on current and power is the importance rate at which an amplifier's output voltage can change over time or slew rate.  I believe slew rate is important because it affects the bandwidth, performance, and distortion of an amplifier.   In my experience I was concerned at first in moving from a  300 watt, high current amp to a 120 watt integrated amp with a smaller power supply transformer to drive speakers that are not efficient by any definition.  The integrated amp had better bass and dynamics, including faster dynamic swings.  The integrated had a much higher slew rate.  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?
 

Another aspirin it is!

To your weight lifter analogy;

I would liken the weight lifter to the amplifier, the weight he's lifting to the speakers, and the power supply to how much muscle (power reserves) he has.

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

@thecarpathian

No, I would not, because they are really two units and both have to be up to par.

I'd say the muscles are the output stages (transistors, tubes, etc.) and heat sinks.  The power supply is the stage he's standing on.  Both have to be strong enough for the weight. 

I'm adding heat sinks because they are a major enabler for Class A and A/B designs.  You will melt your transistors without adequate heat sinks.  Though truth be told the legal requirements to rate an amplifier n Watts may cause many amps to have exaggeratedly large heat sinks for music playing.