It is indeed frustrating that some keep resorting back to the same old blinkered thinking and posting it at every single review.Same arguments, different review... As if we did not have a topic for that already.
It is indeed frustrating that some keep resorting back to the same old blinkered thinking and posting it at every single review.Same arguments, different review... As if we did not have a topic for that already.
John, the fact that you resort to this demonstrates you know the flaw in your argument.
You are even conflating power output and frequency response.
It is indeed frustrating that some keep resorting back to the same old blinkered thinking and posting it at every review.
Oh dear. You don't do a swept frequency response plot from 20-20KHz at full rated power to look for issues at each end of the spectrum? You don't compare that to a 1W or half rated power to investigate power bandwidth issues?
John, this may be uncharitable but you do this at every single review.There's only one person in this thread cutting and pasting the same irrelevant things and it isn't me.
John, this may be uncharitable but you do this at every single review.
You criticise what Amir has done, what tests he hasnt performed, the faults with the tests he has performed, without any thought about the real world relevance or the broader goals of the site.
I havent said dont do power V Frequency testing - I have questioned the real world relevance and importance. You take it as being some kind of direct relevance and highly important to real world audio quality, when it is not that simple and totally misleading to think so.
It's a pro amp and may be used behind a crossover to feed an array of tweeters.Can you explain to me what's the point of testing (in this publication - consider the wider audience) for a condition that will never exist in the real world? You will never see full power at 20kHz, not even vaguely close to it, so can you explain to me why you consider it so important?
Agree.
+ Slew Rate and Damping Factor.
@Amir, @Restorer John, and @March Audio are 3 of my favorite contributors to this site and in this case I can understand their different points of view on amplifier testing as they are all reasonable and valid. I agree with Restorer John's point that the tests should be consistent regardless of the type of amplifier being tested and the reader needs to learn how to interpret them. I think John's point is that it can appear that tests that show the limitations of traditional amps like SINAD and "32 tone tests" are always done but tests that show the limitations of Class D like maximum power vs frequency or square wave are not. While I understand "full power at 20 Khz" is not important to real world listening I have found that limitations like this indicate "something" about that amp that may be important (All filters have "consequences" beyond their primary function like phase shift and transient response).... at the very least it is interesting to learn about and understand the different strengths and weaknesses and I see no reason not to test all amps consistently and thoroughly.
It's a pro amp and may be used behind a crossover to feed an array of tweeters.
John, this may be uncharitable but you do this at every single review.
You criticise what Amir has done, what tests he hasnt performed, the faults with the tests he has performed, without any thought about the real world relevance or the broader goals of the site.
I haven't said don't do power V Frequency testing - I have questioned the real world relevance and importance. You take it as being some kind of direct relevance and highly important to real world audio quality, when it is not that simple and totally misleading to think so.
Would love myself some big CV speakers for surround sound.
That's complete rubbish, Alan, and you know it.
Amir receives in equal quantity, both bouquets and brickbats from me and others, and to state otherwise is plain disingenuous. When he openly considers a further watering down of testing, I'm certainly not the only one around here who thinks it is a big mistake.
My position is backed by the US Federal Trades Commission, Amplifier Rule. If you, or anyone else wants to advertise and sell amplifiers in the US (and other countries benefiting from those standards), they must do so under that rule. Several times the industry has tried unsuccessfully to water down the rules and been over-ruled in no uncertain terms. Minor changes were made to preconditioning, allowances for multi-channel AVRs and powered subwoofers, but the rest is left untouched.
View attachment 44108
Again in 2000 and 2002 and another statement in 2007 essentially leaving it untouched. You can research it yourself.
It applies to you and your amplifiers. They must be able to achieve their rated power and distortion over the advertised bandwidth. Any frequency at full power for 5 minutes. Whether you think it is reasonable or not, doesn't matter one iota. If you want to change it- petition the FTC, in the meantime, ensure your amplifiers are compliant. You can't change the rule by banging on here, and every time you do, I and others will remind you you are barking up the wrong tree- again.
This site cannot and should not become a platform for promoting the weakening of standards, one driven by conflicts of interest and whatever the latest flavour-of-the-month amplifier happens to be.
So, instead of untruths and attempts to silence any voices of dissent, go get the rules changed in your favour. Or play by them.
You sure this rule applies to commercial products like the amp we are discussing?It applies to you and your amplifiers. They must be able to achieve their rated power and distortion over the advertised bandwidth.
Of my 6 amplifiers the newest is from 1979These are both useless metrics. As I described earlier, damping factor is at best a surrogate for feedback factor, and otherwise has no influence on the final sound, and slew rate is also related to descisions in feedback design. Neither have a direct influence on the actual sound, and are only correlated with amplifier performance because they are influenced by, or the result of design descisions. We seem to be in a time warp quoting these useless metrics. Back in the 80's they were all the rage. If your amplifier is competently designed these numbers will usually look good, but that is a consequence of the design regime. You may as well add mass of the amplifier to the list. It too is a consequence of the design choices, but has just as much direct effect on the sound.
You need to bear in mind that this amp is different to most in that i has an ADC at the front end which sharply limits bandwidth hence things like square wave testing become pointless.@Amir, @Restorer John, and @March Audio are 3 of my favorite contributors to this site and in this case I can understand their different points of view on amplifier testing as they are all reasonable and valid. I agree with Restorer John's point that the tests should be consistent regardless of the type of amplifier being tested and the reader needs to learn how to interpret them. I think John's point is that it can appear that tests that show the limitations of traditional amps like SINAD and "32 tone tests" are always done but tests that show the limitations of Class D like maximum power vs frequency or square wave are not. While I understand "full power at 20 Khz" is not important to real world listening I have found that limitations like this indicate "something" about that amp that may be important (All filters have "consequences" beyond their primary function like phase shift and transient response).... at the very least it is interesting to learn about and understand the different strengths and weaknesses and I see no reason not to test all amps consistently and thoroughly.