Amplifier current vrs watts; why is current more important?

But a monoblock amp like the "Legendary" old Mark Levinson ML2 monoblocks that are only 25w!! into 8ohms, will sound better into them, because it’s said they double their wattage for each halving of impedance all the way down to 1ohm with the current it can generate, so they will stay flat in frequency response, where the 500w’ers will sound like a tone control.

What is important is that the amp behave as a voltage source, not whether it can double full power as the load is cut in half. The latter is a subset of the former.

Of course, a good number of loudspeakers in high end audio don't even expect the amp to behave as a voltage source. That is why there are so many successful  zero feedback tube designs, which behave more like a power source.

Doesn't matter what "spin" is put on it, when you have good current, the amp stays flatter in frequency response, instead of looking like a tone control.
An amp needs current along with the watts, as these frequency response graphs show, of the same "wattage" amps with and without good current ability into the same easy speaker load.
https://forum.audiogon.com/posts/1730185

Cheers George


 

Hi atmasphere. I love your amps by the way. If I had reasonably normal loudspeakers I'd have a pair for sure. I have my eye on a pair of Soundlabs which I understand do wonderfully with your MA 2s.
I am not sure I understand your last statement. Are you saying that zero feedback amps can supply more current and would do better driving low impedance loudspeakers?

I am not sure I understand your last statement. Are you saying that zero feedback amps can supply more current and would do better driving low impedance loudspeakers?

No. I am saying that some loudspeakers (like Sound Labs) don't need a very low output impedance in order for the amp to sound right on them. Other examples are most horns, most full-range-driver loudspeakers (like Lowthers) and other speakers where the designer found that he preferred the smoother sound of tubes.

Unless you have a very benign flat impedance speaker (rare) that doesn't wander to much from being a flat impedance between 20hz to 20khz, only then is an amp with watts but little current OK.

You need an amp with both "watts" to suit the dB efficiency to get the loudness you want, and "good current" to keep the "loudness" you want during the "low impedance" dips (that nearly all speakers have).
This stops the amp becoming a tone control, and modifying the flat frequency response. Just as in the graphs I put up.   https://forum.audiogon.com/posts/1730185

Cheers George