Electricity Theory Thread

[jenkinsontherun]

In a class A amplifier stage (by design) the power it takes from the powersupply (call it wall socket) is constant at all times. say 100 watts.
when not playing music, it creates 100 watts of HEAT.
when supplying 20 watts to the speakers, it created 80 watts of heat and so forth.
It runs Cooler when working Hardest!
A class D amplifier creates almost little heat at all times, so it is very efficient - but arguably class A sounds best!
go figure ....

Yes, this part makes sense. Now it's a matter of Googling the details of ClassA/D,AB, etc. Thanks.

 

[Kentajalli]

(Energy from current flow back into neutral socket) = (Energy from current flow from hot hire) - (Energy from wasted heat from amp,speakers,cables,etc.) - (Energy to power speaker driver assembly)

Ignoring ground wire, can we say the above?

Take out the words energy and that would be correct.
Energy does not flow, current (electrons) do - so there is no energy flowing into the neutral or anything.
Energy from the wall socket = energy used properly to create sound waves + energy wasted in all forms
going back to water plumbing analogy again:
Voltage is water pressure
Current is flow rate (how many litres per second)
Energy is function of the combination of the two.
So if we have pressure, but zero flow = zero energy
pressure causes water flow, but if we have narrower pipes (high impedance) or wide pipes (low impedance), the same pressure will have diffrent water flows as a result.

 

[jenkinsontherun]

Take out the words energy and that would be correct.
Energy does not flow, current (electrons) do - so there is no energy flowing into the neutral or anything.
Energy from the wall socket = energy used properly to create sound waves + energy wasted in all forms
going back to water plumbing analogy again:
Voltage is water pressure
Current is flow rate (how many litres per second)
Energy is function of the combination of the two.
So if we have pressure, but zero flow = zero energy
pressure causes water flow, but if we have narrower pipes (high impedance) or wide pipes (low impedance), the same pressure will have diffrent water flows as a result.

Okay, the pieces are beginning to stick together. I have a hunch that this is still the very basic stuff, but still gotta learn it.

Thanks once again!

 

[jenkinsontherun]

What component within an amp regulates the amount of current going back into the neutral socket?

 

[SilverEars]

Take out the words energy and that would be correct.
Energy does not flow, current (electrons) do - so there is no energy flowing into the neutral or anything.
Energy from the wall socket = energy used properly to create sound waves + energy wasted in all forms
going back to water plumbing analogy again:
Voltage is water pressure
Current is flow rate (how many litres per second)
Energy is function of the combination of the two.
So if we have pressure, but zero flow = zero energy
pressure causes water flow, but if we have narrower pipes (high impedance) or wide pipes (low impedance), the same pressure will have diffrent water flows as a result.

This man understands the deeper meaning of what the parameters actually stands for. This is the perfect analogy.

 

[jenkinsontherun]

Hey @SilverEars , welcome back! Mind answering my question? ^_^

 

[jenkinsontherun]

bump

 

[Smallpie]

Bump, im on board and listening too. Good questions and answers. Class begins lol

 

[Kentajalli]

What component within an amp regulates the amount of current going back into the neutral socket?

Your question assumes that there is a notion of "current going back to neutral pin" which is non sequter (I will explain later)
Here is the answer to the question " ......... amount of current used"
Different amps of different designs, do it (wait for it ......) differently !
In a typical Class A/B amplifier, as the volume is pushed up (or the music goes louder) the very last stage of the amplifier (output stage) starts to conduct more of the available power from the wall socket into the speakers, so more current is allowed to flow.
Water analogy: the last water tap is openned more to allow more water to flow.
On a class D amplifier, the output stage switches on for longer period of time, so on average during a period of time more current is allowed to flow.

Do not think of current flowing back into neutral pin, that is of no consequence here.
The neutral pin is there simply as a zero voltage ref pin. Imagine you blow up a baloon - if you let neck open the air flows out, why? - because the outside is of lower air pressure compared to the baloon!
The ballon Requires the lower pressure surrounding in order to baloon-up.
The live wire requires the neutral pin as a sinkhole/outside lower pressure in order for it to function.
picture an old fashion water mill.
What is of interest is, how much river flow water we have, what speed it is running at. after we finished with it, how much of the water flows into the ground or the ocean is of no consequence.

 

[jenkinsontherun]

Your question assumes that there is a notion of "current going back to neutral pin" which is non sequter (I will explain later)
Here is the answer to the question " ......... amount of current used"
Different amps of different designs, do it (wait for it ......) differently !
In a typical Class A/B amplifier, as the volume is pushed up (or the music goes louder) the very last stage of the amplifier (output stage) starts to conduct more of the available power from the wall socket into the speakers, so more current is allowed to flow.
Water analogy: the last water tap is openned more to allow more water to flow.
On a class D amplifier, the output stage switches on for longer period of time, so on average during a period of time more current is allowed to flow.

Do not think of current flowing back into neutral pin, that is of no consequence here.
The neutral pin is there simply as a zero voltage ref pin. Imagine you blow up a baloon - if you let neck open the air flows out, why? - because the outside is of lower air pressure compared to the baloon!
The ballon Requires the lower pressure surrounding in order to baloon-up.
The live wire requires the neutral pin as a sinkhole/outside lower pressure in order for it to function.
picture an old fashion water mill.
What is of interest is, how much river flow water we have, what speed it is running at. after we finished with it, how much of the water flows into the ground or the ocean is of no consequence.

ahh I sort of get it. Very coherent answer and anologies. It's like providing room so that electron displacement can happen. @SilverEars mentioned that typical wall outlets (in North America) use AC and not DC. So, the neutral just acts like a storage bank of sorts for the current. In AC power, when the electrons are oscillating back and through the equipment (amp, speakers, cables), it must have somewhere to displace to (and displace from(!) since it's AC), and the neutral socket serves this purpose.

So, as you stated, the amount of current used is the current being passed back-and-forth in an AC scheme, and neutral is just there to accept the current on the other end. The amp ultimately decides the current draw from the hot pin.

So let me follow up, if electricity from the wall is AC, this means the neutral is just as capable of providing current as accepting it? Or is this wrong thinking.

Thanks!

 

[Kentajalli]

, if electricity from the wall is AC, this means the neutral is just as capable of providing current as accepting it? Or is this wrong thinking.

Thanks!

Short answer is yes, neutral can and does, but it is not a storage tank at all, you see electrons are every where, within your body, within air and vaccum! indeed they travel better in a vaccum, electricity is the movement of electrons fro any reason, so instead of the neutal pin, you could use a big metal shaft inserted into mother earth.
But I am warning you, do not get so tangled up with the neutral pin, you will confuse yourself in the end. The neutral pin is just a necessity - something to close the circuit with, a sinkhole for our water plumbing.
Also providing electrical power in DC form is troublesome and inefficient, indeed Edison in early days designed, built and operated DC power stations. You may want to google that at your leisure.
So all electricity grids are AC, but our amps and DACs work with DC, so every equipment has a Power Supply Unit or PSU, the job of this section is convert the grid's AC into a clean, stable DC, to provide power to the rest of the system.
A PSU may have multiple sections providing different voltages for different sections.
However your washing machine, fridge or stove happily work on AC.

 

[jenkinsontherun]

Short answer is yes, neutral can and does, but it is not a storage tank at all, you see electrons are every where, within your body, within air and vaccum! indeed they travel better in a vaccum, electricity is the movement of electrons fro any reason, so instead of the neutal pin, you could use a big metal shaft inserted into mother earth.
But I am warning you, do not get so tangled up with the neutral pin, you will confuse yourself in the end. The neutral pin is just a necessity - something to close the circuit with, a sinkhole for our water plumbing.
Also providing electrical power in DC form is troublesome and inefficient, indeed Edison in early days designed, built and operated DC power stations. You may want to google that at your leisure.
So all electricity grids are AC, but our amps and DACs work with DC, so every equipment has a Power Supply Unit or PSU, the job of this section is convert the grid's AC into a clean, stable DC, to provide power to the rest of the system.
A PSU may have multiple sections providing different voltages for different sections.
However your washing machine, fridge or stove happily work on AC.

Yeah coincidentally I read an article on that, and due to line losses, power plants were placed close to consumers.

 

[Kentajalli]

Yeah coincidentally I read an article on that, and due to line losses, power plants were placed close to consumers.

An electricity line is basically a resitor between power plant and the consumer.
Losses are due to heat generated when current goes through the resistor.
Now this loss depends on two things:
1- the resistance of the line
2- the amount of current, squared - menaning 2X the current = 4X heat waste
To limit the loss we need to address those. A thisker cable, better junction boxes reduce the waste.
But what if we could reduce the current? we get a squared benefit.
You see with AC we can have our cake and eat it!
Current and voltage are related, twice the voltage but half the current has the same power.
We simply use our generated AC supply, put it through a transformer to up the voltage to few thousand volts, this will reduce the current considerebly.
The losses through the cables is reduced geometrically - just before we supply consumers, we use another transformer to reduce the voltage and up the current.

 

[jenkinsontherun]

I found a very nice animation in this link:

https://www.highfidelitycables.com/technology/

Scroll down a bit and you will see, it's a typical dynamic driver working.

I have a potentially loaded question.

How is an amp able to produce such precise swaps in voltage as to create music that is so detailed to our ears? Do we just have to accept that through decades of innovation, that technology is able to do this? Anything to note here?

Thanks.

 

[jenkinsontherun]

On another note, it's surprising how a consumer electronics page describes electromagnetism much better than blog articles dedicated to that same topic.
But let's leave out electromagnetism aside, and focus on how an amp can amazing create this precise voltage swing.