Whi HiFi power ratings are low

[Steben]

[StephenGiles]

Put the Hifi high and the lights down low!!

[Paul Perry (Frostwave)]

Put the Hifi high and the lights down low!!

With a decent sized HIFI, you only need to do the first, the second will happen automatically.....

[George Giblet]

Can you make a statement of the "lie"?  I'm not sure if I understand you.

Most HiFi amps have a high loop gain and so they clip fairly hard.

[Steben]

Most HiFi amps have a high loop gain and so they clip fairly hard

Yes, thats the straight line I drew.
The curvy one is for example a tube or MOSfet amp without feedback. I mean HiFi purists will speak of for example 70% of the real power, because beyond that the THD is too high in HiFi terms.

So when someone says "efficiency goes up with feedback and current source" they mean the loss of distortion in that arean bringing the HiFi power to the max. In guitar terms, the power always is the max, only with a lot of distortion.

[George Giblet]

I suppose the bottom line is maximum power is just a number, you can quote it many ways.  When you have non-linearity involved and power vs distortion trade-offs it's possible to play around with the numbers.  I wouldn't call it a "lie" as such, it's a valid statement according to definition - just how meaningful that is in real terms is another story!

Below clipping I'd say the solid state feedback amp does provide low distortion and high efficiency.  Once you go beyond that the amps will have their own sound.

[Thomas P.]

I wouldn't call it a "lie" as such, it's a valid statement according to definition - just how meaningful that is in real terms is another story!

Just like "Class A" in guitar amps
But honestly - have anyone of you bought a hifi-amp for your room because of the power rating???

[Steben]

I wouldn't call it a "lie" as such, it's a valid statement according to definition - just how meaningful that is in real terms is another story!

Just like "Class A" in guitar amps
But honestly - have anyone of you bought a hifi-amp for your room because of the power rating???

Good question. It makes you wonder why we all don't put a stereo LM380 amp together for our CD player. 2 x 1W is very nice you know. Already loud enough to enoy the neighbours if you have efficient speakers.

Guitar amps however are often chosen by their power to stand up against another amp or a drum kit.

[Sir H C]

I have a nice Threshold CAS-2 power amp for my home stereo.  100 watts per channel, and it actually did improve the sound of my system over the Adcom GFA-555 that I used before.  This is a reasonable medium in the audiophile world, negative feedback used, but not anything too crazy.

I love Nelson Pass's work, he often will explain everything he does in engineering terms that make sense.