Amplifier current vrs watts; why is current more important?

those 1, 2, 15 W watt amps are useless.

Really,... have a list to these 20w only into 80hm amps, and say that again.
https://img.canuckaudiomart.com/uploads/large/2097160-65b80b07-mark-levinson-ml2-class-a-mono-block-...

Even though the OP’s title is
"Amplifier current vs watts; why is current more important?"

Just to take it off topic as oddio did, with his (excuse me) even grosser misinformation.
To show why output impedance (damping factor) is not the only cause for "tone control" behaviour, but also "available current" is just as if not more important.

Here is a typical case where "current" ability is the factor to making a flatter frequency response, more so than output impedance (damping factor)


Here are two very similar (save for their current ability) amps solid state linear each 60w into 8ohms, but their output impedance (damping factor) is more that 10 x different from each other, these are frequency response measurements (black trace) into exactly the same Kantor simulated speaker loads.
NB: Make sure you see what the graph graduation scale is for both.

1: This Budget Schiit is the one with lowish current , but the "best" lowest output impedance ( best highest Damping Factor) of DF=226 Output impedance=0.03ohm It’s FR is +- 2db
https://www.stereophile.com/images/416Schiitfig01.jpg

2: This Pass Labs one with high current but, worse 10 x higher output impedance and worse 10 x lower damping factor especially in the bass, and yet has far better control over the same simulated speaker load. It’s FR is only +- 0.025db!!!!
https://www.stereophile.com/images/1116Pint60fig01.jpg

As you can see the one, 1: with the "best" lowest output impedance (highest damping factor) is the one behaving like a "tone control" more that the other!!!!!!.
This is because the Schiit is current is limited into the low impedance loads of the simulated Kantor speaker load compared to the Pass labs.

Now back on topic, sorry hiendmmoe

Cheers George

The " tone control" effect you speak of is due to output impedance of the amp.

Yes, this also as well on top of current starvation we’re talking about.

Any amp that has low damping factor, (output impedance is that high) should not be considered as well if one wants an amp that will not sound "coloured" and stays flat in frequency response.

Cheers George

 it could be done more specifically and more consistently with an equalizer than with the chance

So true, why have an amp that can't maintain a flat frequency response, into a speakers wavering impedance load, you may as well have a graphic equalizer, at least with it you can pick where the boost and cuts of the frequencies are going to be.

  Look below at the black wavy line, that is the frequency response you will hear!!, and that's into an easy simulated speaker load, a hard load will be even worse

This is the well known Prima Luna Prologue Premium 25w tube amp with very questionable current.

8ohm tap + - 7db!! frequency response, "a tone control"
https://www.stereophile.com/images/1116PLPPfig01.jpg

4ohm tap+ - 5db!! frequency response "still a tone control"
https://www.stereophile.com/images/612PPPfig01.jpg

Here is the Pass XA25 25watter with far more current that the PL above, it’s +- 0.1db frequency response. Virtually flat as it should be!!!
https://www.stereophile.com/images/218PXA25fig1.jpg

Cheers George

And for me, that’s OK and perfectly fine. A little response tailoring often suits me. It’s not your place to decide what’s OK for folks.
It’s just that we don’t all want that.

  
No need to get your knickers in a knot.

That fine, if you're willing to take the chance, as the "response tailoring" as you so quaintly call it, will be different for every speaker you put it on.

 So you never know if your going to like the "tailoring" it's doing until you bought it.
BTW: It's still a tone control that doing EQ, which ever way you look at it, which will be a different EQ for every different speaker.

Cheers George

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

Get over it.

Bit rude! that response for being shown the truth. After all it’s what the subject of this thread is all about.
Educating is a form of telling, and if you don’t want to learn why current is needed from an amp, and what happens when they don’t have enough for the load they’re seeing and become tone controls because of it, then don’t listen or partake in the discussion

Cheers George

Thanks for the heads up andy.

Cheers George

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


 

viridian
So I do it backwards and choose the amp first.

That’s fine, so long as the speaker then chosen doesn’t cause that amp to become a "tone control"
To me I would think in that easy "Kantor Simulated Speaker Load" graphs I posted above, that Stereophile uses, that +- 1 or 2db deviation from flat would be acceptable.

That means easier loads than the "Kantor" horns, JBL ect the amp would be almost flat and on harder to drive than the "Kator load" the deviation would still be just acceptable at +-3db deviation from flat.
.
Cheers George

Here is proof to what I posted above, and the speaker load in both instances, is a very easy to drive Kantor simulated speaker load, a bad load will look far worse.

Look at the black wavy line.

This is the well known Prima Luna Prologue Premium 25w tube amp with very questionable current.

8ohm tap + - 7db!! frequency response, "a tone control"
https://www.stereophile.com/images/1116PLPPfig01.jpg

4ohm tap+ - 5db!! frequency response "still a tone control"
https://www.stereophile.com/images/612PPPfig01.jpg

Here is the Pass XA25 25watter with far more current that the PL above, it’s +- 0.1db frequency response. Virtually flat as it should be!!!
https://www.stereophile.com/images/218PXA25fig1.jpg

Cheers George

Amplifier current vrs watts; why is current more important?

KEEPING IT SIMPLE.
Amps with big watts and little current alone don’t drive speakers with low impedances and stay flat in frequency response, amps with big current do.

EG: One of the worst low impedance speakers ever made, the Wilson Alexia v1, they go down to 0.9ohm in the bass.
A 500w stereo P.A. amp or a 500w Class-D will work into them to a point only, but will sound like a tone control.
 
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.

Cheers George