What does this mean on an amplifier

[ForceEdge]

" extremely high total system efficiency of ~80% (power supply is rated at >90%, output stage is rated >90%)."

I understand the efficiency aspect, but what does power supply is rated blah blah and output stage is rated stuff mean. What does that mean exactly. How efficient is this amp when I have it running?

[maylar]

The total efficiency of an amp is the combination of the internal power supply and the amp output circuitry. Having designed power supplies for a living I can say that 90% is really good for a high power supply. 80% is typical.

A Class AB power stage has a theoretical maximum effieciency of 75%. Combine that with an 80% efficient p.s. and you get 60% total. The one you're quoting is bragging, rightfully. And I would assume it's a Class D, right?

[ForceEdge]

The total efficiency of an amp is the combination of the internal power supply and the amp output circuitry. Having designed power supplies for a living I can say that 90% is really good for a high power supply. 80% is typical.

A Class AB power stage has a theoretical maximum effieciency of 75%. Combine that with an 80% efficient p.s. and you get 60% total. The one you're quoting is bragging, rightfully. And I would assume it's a Class D, right?

Yes its a class D. Its the Alpine pdx-f4
What is output stage percentage
and what is power supply percentage?

It says 80% but what does in mean in the parenthesis because in there it says in does 90?

[maylar]

There are 2 main sections to an amp; the power supply and the amplifier circuits. Both have a certain effiency. The total effieciency is a combination of the 2. So if the amp circuitry is 90% and the power supply is 90% the total effiency is 90% x 90% = 81%.

So the power required from the battery is (output power / 0.81).

Normally manufacturers don't list them separately, they only show the total.