Solid State Amps - Power Rating

MHT said:

Hello there,
I have a technical question for the electrical engineers out there. An audio consultant mentioned that an amp's maximum power consumption is more important in producing a dynamic sound than its rated power output.
For example, a Pass Labs x350.8 stereo amp is rated 350W/channel @ 8ohms has a maximum current draw of 550W.
On the other hand, a Plinius SB301 is rated 300W @ 8ohms but has a max draw of 900W.
A more extreme difference is something like the Soulution 511 which is rated a mere 150W into 8ohms but can draw as much as 1600W, indicating its ability to produce the most power when required.

Is this the right away to understand an amp's power?

Many Thanks

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Yes and no.
There are all kind of funky power-ratings. The peak mains traw lets you "triangulate" the max power out. Also depends on the load.
For example the soulution is conservatively rated and should operate relatively efficient. The peak power of the amp should be somewhere above 800W [8 Ohm].
But you never know the total efficieny. For example Class D is at 60 to even 70%. Class A is around 30% Class AB is around 50%.

Do you listen at maximum loudness level?
This kind of stuff matters to the pro audio guys that are doing large sound systems.

In hi-fi systems, no single value can represent all situations. The loudspeaker impedance curve is a big part of the equation. And are you playing music, movie crash scenes or extended test tones? Different demands for each.

You're comparing efficiency, not power that can go to the speakers. The watts per channel pertains to speakers, and the max wattage used pertains to how much of a space heater the amplifier happens to be.

A high max wattage used is not an indication of peak power. Many of those may be able to produce more power than rated, during peaks, but that doesn't mean it has any relation to the max wattage used. They may lose classA at peaks.

Most of those are classA, which as you can see can drop to even below 10% efficiency. The thing about transistors operating in class A is that they have to have incredibly high bias currents in order to remain in classA, so you can have a 10wpc amp that burns off 300w of heat.

The limitation of power to the speakers is related to the voltage inside the amplifier, in that the max voltage is the max volume in wattage also. Biasing is not relative to the voltage in the same way, it can simply go up infinitely, well, until something melts because it cannot draw that much current without overheating.

With high impedance loudspeakers, maximum power is related to the DC supply voltage. Increase the signal and the amp goes into clipping.
With low impedance loudspeakers, maximum power is related to the DC supply current. Increase the signal and the amp goes into current limiting mode.
Efficiency of AC input power to audio output power is related to amplifier design Class and some other design factors. Class A has low efficiency while class D as high efficiency while the other classes are in between.