I am still waiting for someone, anyone, to tell me: How do you get more than 250W of electrically useful power out of a 10V source with a 0.1Ω impedance?

 

The 100% efficiency was in regard to core losses in the transformer, not those wrt the 0.1 ohm source impedance.

You've got 10 VRMS to work with in series with 0.1 ohm. A dead short is going cause the source to burn 1000W with nothing to the load. An open will burn nothing, still with nothing to the load. A 0.1 ohm load will share a total of 500W between both, or 250W each. So, yes, 50% overall efficiency.

Remember, we are talking max power transfer, not efficiency. Please demonstrate a topology that provides more than 250W to the load with the given 10VRMS @ 0.1 ohm source. Switching is not allowed -- the source signal is already in its final form.

I didn't disagree that 250W is the most you can get from a 10V, 0.1Ω source to an external load, it was just your efficiency value I took issue with.

 

...it was just your efficiency value I took issue with.

"Took issue with" meaning "misinterpreted"?

 

I did not change the conditions of the test, you did. You made an absolute statement, I offered one case where it does not hold true.

When delivering power the 250 watt maximum would apply. When used as a simple heater the system can provide four times that power.

 

Try the other back.
That would give 50% efficiency.
That's why they don't typically match the source to the load with a solid-state audio amp since it significantly increases the output stage dissipation.
Also they don't need a transformer to get high audio power levels.

They do normally use transformers to match source and load in tube amps because the tube impedance is so high and you want all the power you can get with tubes.

Even back in the ancient of days, high end tube amps had selectable "damping factor" which simply selected unmatched output impedances...primarily to give better transient response.

 

"Took issue with" meaning "misinterpreted"?

No.
You did not initially state that 100% referred to the transformer efficiency so I don't see how you can say that my assuming you were not referring to the overall efficiency is a "misinterpretation."

 

Even back in the ancient of days, high end tube amps had selectable "damping factor" which simply selected unmatched output impedances...primarily to give better transient response.

I had an old tube amp that varied the feedback to change the damping factor.

 

No.
You did not initially state that 100% referred to the transformer efficiency so I don't see how you can say that my assuming you were not referring to the overall efficiency is a "misinterpretation."

I was clearly referencing the transformer in the post. That's what the post was about. My intentions were clear and correct. Your interpretation was wrong.

 

I had an old tube amp that varied the feedback to change the damping factor.

I think Dynacos changed the feedback. My Beastie Altec just had a bunch of taps on the input of the transformer.

 

I did not change the conditions of the test, you did. You made an absolute statement, I offered one case where it does not hold true.

When delivering power the 250 watt maximum would apply. When used as a simple heater the system can provide four times that power.

Only if you change the definition of "load", which in this case is clearly electrical.

 

I was clearly referencing the transformer in the post. That's what the post was about. My intentions were clear and correct. Your interpretation was wrong.

Of course your intentions are clear and correct to you, but that doesn't mean your statement was clear and correct to everyone else who read them.
But I will stop here since I understand who I am conversing with and this is obviously not going anywhere.

 

I have read the Maximum Power transfer theorem which states that Maximum power will be transfered from the source to the load only when the source resistance is equal to the load resistance.

I understand.
But why should the resistances be equal for maximum power transfer ?
Please explain the concept behind it.

I have also read that, incase of unequal impedance between the source and load (impedance mismatch) - Reflections of signal from load to source occurs.
What does this imply?
Will the source take up the power reflected from the load? Isn't the source just a pumping device? Why will it accept the power pushed by the load to it?

Analogy or example will give me more clarity.
Thanks!

Maximum power when the product of voltage and current is highest. A mismatch might give a higher voltage but a lower current, or a higher current at a lower voltage. Maximum V x I when impedance is a match.
(100 words or less answer.)