Which is better?!

[quackhead 10+ year member]

size requirements?

 

[disturbed471985 5,000+ posts]

Wrong again.

Right again.....

 

[quackhead 10+ year member]

I presume thd increases as the amp becomes more unstable, er as the output impedance decreases...I have seen a 1% thd spec @ 1 ohm, whereas the same amp specs a .05% thd @ 4 ohms. these figures tell my feeble brain to expect roughly a 10 fold in THD per ohm drop. So simply by that conclusion, I guess a rating of 1% at 4 ohm could reflect 10% at a more unstable 2 ohm load. All this may be inaudible....but it looks like poo on paper.

 

[bubbagumper6 5,000+ posts]

I presume thd increases as the amp becomes more unstable, er as the output impedance decreases...I have seen a 1% thd spec @ 1 ohm, whereas the same amp specs a .05% thd @ 4 ohms. these figures tell my feeble brain to expect roughly a 10 fold in THD per ohm drop. So simply by that conclusion, I guess a rating of 1% at 4 ohm could reflect 10% at a more unstable 2 ohm load. All this may be inaudible....but it looks like poo on paper.

10% distortion would be more than audible. I don't think you can make the assumption that distortion increases linearly as impedance decreases.

The face of the matter is, none of you have any idea what the standard truly encompasses because you've never read it (nor have I) but you're merely repeating what you've heard on this forum in the past (something I've seen done many times over). Judging solely on the basic information they provide on the CEA 2006 website it's obvious to me that the measurement must remain below 1% THD (this is where I said you were incorrect Disturbed) and the standard also provides provisions for other impedance loads. If I were to guess as to what those provisions are (now here is where we get into speculation) I would say the standard would not allow companies to publish ratings for other impedance loads unless they also conform to their testing specifications (as in under a certain voltage and THD level).

But to say that the standard is useless is kind of counterproductive to the entire industry, at least the Consumer Electronics Association is TRYING to establish a bit of credibility for amplifier ratings, otherwise you get companies like PYLE or Power Acoustik releasing amplifiers that claim 5,000w and really produce 50. As far as I'm concerned standards are a benefit for the entire industry.