Why do I need power management if I have a great power cord?

Basic physics. Everytime you double the size of a conductor, you reduce the resistance of the conductor by half. Output impedance is the product of LCR. Reducing any aspect of the impedance allows the available current to increase (the current well). Instantaneous power demands in audio are not often spoken about. Take the Telarc recording of the 1812 Overture as an example. Someone smarter than me did the calculations on the reproduction of the cannon shots in that recording. To accurately reproduce that event considering the average listening level of 2 watts would require 10,000 watts of instantaneous power.

The capacitors only get filled up when they are at or below the voltage coming out of the transformer-rectifier-regulator. That physically is happening in a rectified sine wave that operating at 120 Hz. So there is a great deal of time (maybe a 1/4 of the time), where the AC is NOT feeding the capacitors any DC.

The power supply in an amplifier is holding DC and buffering the AC to provide that energy reserve..

This is pretty much analogous to how a toilet works. The thing flushes very quickly, but takes many seconds to fill the bowl. The pressure and size of the pipes coming into the house do not go directly into the flushing… they merely keep the bowl filled for subsequent flushes, thereby buffering the demand for water.

The power distribution cable from the transformer to the entry service is #2 wire.

For the entire house… running an electric oven, AC, etc. It is not for a single (0r pair) of MB amps that draw 900W (~9A) each.

It just makes sense, logically and mathematically, to supply a dynamic system with huge instantaneous current demands as much current as possible.

Do the lights in the house flicker whenever the bass drum hits?
If not, then the amp is not pulling that output power directly from the input AC.

It is buffering the energy in the capacitors.

A Class A PASS XS300 monoblock will dump 48A on demand.

How do we arrive at 48A? Are you using 8 ohm speakers? Or what is their impedance?
300W at 8 ohms implies “rails” at ~50V, and at 8 ohms that is about 6 amperes.
(Driving a 1 ohm load can get us to 48A - so I guess you have 1 ohm speakers?)

In any case that amp is a device providing voltage amplification and impedance matching. It is not forcing 48A into the speaker, it is only providing up to 50V. The speakers get whatever ohms law translates into in terms of current.

You need two of these. See where this is going?

Not exactly… no.

Holmz, there is no future in trying to have a cogent discussion with a person that misses 90% of the conversation to dwell on 10%. You are obviously so much smarter than I am.

To quote directly from one of many reviews on the Xs300: "The Xs 300 mono amps were not only better sounding in every respect than the XA-160.5s, but they had nearly twice the power: 300 watts into 8 ohms, 600 watts into 4 ohms, and 48 amps worth of peak output current."

Let’s take your analogy to the opposite side of your argument. 900W represents 7.8A @ 120VAC. 24AWG wire has a current rating of 8A. Are you willing to use 24AWG on the Xs300? Ask yourself why Nelson would use a Neutrik powerCON rated for 32A @ 250VAC.

 

Holmz, there is no future in trying to have a cogent discussion with a person that misses 90% of the conversation to dwell on 10%. You are obviously so much smarter than I am.

How do you arrive at concluding that I am smarter than you?
I am just trying to understand here, and make sense of the physics.

What is wrong with me only needing further explanation of 10%?
Maybe I got the other 90%

Let’s take your analogy to the opposite side of your argument. 900W represents 7.8A @ 120VAC. 24AWG wire has a current rating of 8A. Are you willing to use 24AWG on the Xs300?

No!
would probably use whatever cable Nelson provided, or I would ask him.

Ask yourself why Nelson would use a Neutrik powerCON rated for 32A @ 250VAC.

The output of the amp needs to be larger speaker cable because the voltage is lower and there the current is higher for the same wattage.

The PowerCon is a great connector. I think that they only come in 32A, and that covers most all professional needs. Is that between the seperate power supply and the amp? Or is it from the wall to the amp? If it is “between” then it makes sense as the separate box is probably supplying 50V “rails”, so it needs be higher current capability than the 120v side is.

If one is using a 12 gauge wire for the speaker, then the incoming power, being at 120v, should not need to be bigger than 12 gauge (If we assume that the amp was 100% efficient). The amp is not 100%, but the 120v is a lot higher than a 50V rails so the current will be lower on the AC side.

The whole thing about 2 gauge coming to the house, is to cover things like ovens and dryers which need huge amounts of power/current.

a 1kW hair drier or 900W amp does not need 2 gauge.

@bruce19 

So my observation is that a blacker background on a tv does not make the programming better or worse. However if you focus on the blackness of the background you can make yourself unhappy with your equipment. Is that a smart thing to do?....Is there such a thing as 'optimal stopping' in audio? I think so.

I would agree that there is such a thing as optimal stopping. What I have found recently -- by adding a relatively inexpensive linear power supply to my streamer -- is that the content (or "programming") *did* get better because I was able to hear instruments and notes that were not previously available to me. If that occurred by adding better power to my whole system, it would be quite reasonable to do.

So,  perhaps, one metric to answer your excellent question -- roughly, "When is it optimal to stop improving the system?" -- is this: *when no more content is added or improved significantly.* Or even, *when I cannot justify spending this money, here.*

Knowing when to stop is kind of a judgment call which comes down to each of us. It's that same part of us that knows when to stop eating at an "all you can eat" buffet!

@holmz 

Exactly so, A large,  fast,  over spec’d capacitor bank in a power supply is the key. 

“ 

The capacitors only get filled up when they are at or below the voltage coming out of the transformer-rectifier-regulator. That physically is happening in a rectified sine wave that operating at 120 Hz. So there is a great deal of time (maybe a 1/4 of the time), where the AC is NOT feeding the capacitors any DC.

The power supply in an amplifier is holding DC and buffering the AC to provide that energy reserve..“