We all know RMS power capacity, dynamic power capacity, frequency response, current capacity, output impedence and distortion are important measures.
What else is important in an amplifier. How can we tell an amplifier is of high quality based on hard engineering measurements.
I know that auditioning is needed to detect finer points of amplifier design. But here I am looking for things that can be objectively measured.
What can we measure in NAD and Parasound that is not available in Yamaha, Denon or Onkyo.
What else is important in an amplifier. How can we tell an amplifier is of high quality based on hard engineering measurements.
I know that auditioning is needed to detect finer points of amplifier design. But here I am looking for things that can be objectively measured.
What can we measure in NAD and Parasound that is not available in Yamaha, Denon or Onkyo.
Set constant input frequency ... for example 1KHz.....and write down output voltage (any value that u want to set).....Then pump hot air in to the casing ...... or blow it over the all parts.....and check what is going with the output (u should go up to 60deg)......then try same but with heating different parts of the board while other r on lower temperature (after first test when all is on room temperature).If output change is zero design is good.....also if u remove input signal and do the same tests again u should have zero change in duty cycle.If all is good u have very stable design as i do 
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Often, there is no genuine difference. If the response is flat to 100kHz, harmonic distortion is sufficiently below -75dB at all frequencies, noises and beats of all types are below the hearing threshold, square wave & impulse response reveal virtually no abberations or slewing, crosstalk is minimal, interference rejection is satisfactory, and there is no pre or post-ringing, then they will be performing identical. As such, they do sound identical. Beyond that, one may wish to look to ensure that internal components are adaquately chosen and that the product offers adaquate headroom and safety to drive the load for the application.
All properly designed amplifiers perform identical and faithfully reproduce audio waveforms to a degree of accuracy that is beyond human auditory descrimination. In order for any two to sound different, they must perform different and to such degree that differences are above the auditory threshold. Those that induce high distortion belong in two catagories; substandard design and intended distortion. Where distortions are all minimal, the sole reasons that audiophiles believe that their expensive big name amplifier sounds better or different at all from a HT receiver are entirely the effects of their integral auditory bias system. It's in their heads, not anything that the amplifier is doing. An ABX test isolates the biases and will confirm this.
Electrical energy in an amplifier only has two tuples; magnitude versus time, it's two dimensional. Power is the relationship between voltage and current in time, including any reactance that is present. As such, waveforms are entirely quantifiable with the appropriate techniques and equipment. However, there are several tests, including those I've mentioned, that are commonly overlooked and taken forgranted by some manufacturers and hobbyists.
One of the companies you have mentioned is flatly exempt from any such ignorance - Yamaha. They put their designs under serious testing scrutiny, both empirical and subjective. In Tom Nousaine's paper, one of their mid-grade HT receivers was used in an independant ABX test versus a set of $14,000 Pass Labs class A monoblocks, and they were sonically indistinguishable to all those subjects involved in the listening test, including the owner of the monos.
All properly designed amplifiers perform identical and faithfully reproduce audio waveforms to a degree of accuracy that is beyond human auditory descrimination. In order for any two to sound different, they must perform different and to such degree that differences are above the auditory threshold. Those that induce high distortion belong in two catagories; substandard design and intended distortion. Where distortions are all minimal, the sole reasons that audiophiles believe that their expensive big name amplifier sounds better or different at all from a HT receiver are entirely the effects of their integral auditory bias system. It's in their heads, not anything that the amplifier is doing. An ABX test isolates the biases and will confirm this.
Electrical energy in an amplifier only has two tuples; magnitude versus time, it's two dimensional. Power is the relationship between voltage and current in time, including any reactance that is present. As such, waveforms are entirely quantifiable with the appropriate techniques and equipment. However, there are several tests, including those I've mentioned, that are commonly overlooked and taken forgranted by some manufacturers and hobbyists.
One of the companies you have mentioned is flatly exempt from any such ignorance - Yamaha. They put their designs under serious testing scrutiny, both empirical and subjective. In Tom Nousaine's paper, one of their mid-grade HT receivers was used in an independant ABX test versus a set of $14,000 Pass Labs class A monoblocks, and they were sonically indistinguishable to all those subjects involved in the listening test, including the owner of the monos.
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The upper frequency limit is commonly set by miller effect, which introduces slew-induced transitory intermodulation. Placing the -3dB point three octaves out of band mitigates the effect, whereas setting too high increases the susceptability to interference, or instability for the designated gain. However, 200kHz should not be a problem. 100kHz is a minimum and easily attainable figure that balances the weight of both in a broad range of topologies.
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Also what do you think about Yamaha RX-V800. It says 100 wpc from 20 to 20khz in 8 ohm. Not sure if it is on both channels at the same time. The spec does not clarify. But the way they write it it seems so. A lot of dynamic power. Looks like 100 wpc is plenty for me if I can believe the spec. Do I still need to replace it with a Parasound or a Krell
I have no opinion of this model, since I am not familiar with it. That said, Yamaha traditionally always measured their gear in accordance with IHF standards for both front channels at the same time. 100W Provides 10dB headroom for 10W average output power, with more headroom at lower listening power levels. The initial question would be "am I clipping my receiver's amp stage on dynamic swings at my usual listening levels?". This really depends on how high the dynamic peaks are and how loud you listen. The second question would pertain to which models of Krell or Parasound being considered as a replacement. The RX-V800 isn't one of their higher performance models, but frequency response is presumably flat and harmonic distortion levels are close to several Krell amps. The only tangible difference is power, and Watts are cheap today.
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Uh-oh . . . Uh-oh big time. Member kouiky in his post above said something worthy of the now dead audio god (of the Measurements Gang) Julian Hersch :
" ALL PROPERLY DESIGNED AMPLIFIERS PERFORM IDENTICAL "
But then kouiky did something else which will likely generate one Hellish bar fight : he referred to a true genius of the divinely inspired sort (Nelson Pass) and his class A mono blocks in a dismissive way.
I am putting on my Kevlar jockstrap, microwaving popcorn, gettin' out the single malt decanter, and staying up extra late for the upcoming fun ! ! !
" ALL PROPERLY DESIGNED AMPLIFIERS PERFORM IDENTICAL "
But then kouiky did something else which will likely generate one Hellish bar fight : he referred to a true genius of the divinely inspired sort (Nelson Pass) and his class A mono blocks in a dismissive way.
I am putting on my Kevlar jockstrap, microwaving popcorn, gettin' out the single malt decanter, and staying up extra late for the upcoming fun ! ! !
^And, calling out any of it with the extant claim that I've written something incorrect, unique, or esoteric without supporting your own subjectivist position underlines a critical error of judgement in itself. If you disagree, try forming a critical argument and support it with validated science, not mere rhetorical plunder, nor conjecture.
Cannot be evaluated unless you consider it along with the speakers used (and th ecable that connects them)
dave
Hi,
Measurements are a poor way of judging amplifiers. According
to them all valve amplifiers sound poor, but they simply don't.
Not that you could not attempt to measure amplifiers for sound
quality, its simply the measurements are simply not good enough.
By a long way current measurements only indicate cheap amplifiers.
Advanced and complex measurements are not only expensive,
e.g. IMD, there is no concensus as to their meaning, whilst
things like THD+N are simple and cheap, and everyone knows
how it is derived, and all agree in a general concencus that
the lower it is the better generally, but not particularly.
I.e. valve amplifiers versus solid state THD+N is useless.
Its not going to change, THD+N is pretty useless comparing
solid state of various topologies with similar numbers, and
as ever, vanishing small THD+N figures are being chased.
Publishing of THD+N spectra would be a way forward,
but that isn't going to happen in the big wide world.
For sure armed with some serious measurement kit you will
only prove that a Krell seems to be seriously overpriced
compared to a Yamaha, that is because it is, in any
sensible reality, the Yamaha is far better VFM.
Is it just as good ? TBH for most systems probably.
Which is better ? The Krell probably, but not certain.
rgds, sreten.
FWIW I'd consider my favourite used budget amplifer,
the Pioneer A-300X, about £60 used, capable of being
used with any quality used speaker under about £1K.
FWIW a suitable quality CD player used is about £30.
Measurements are a poor way of judging amplifiers. According
to them all valve amplifiers sound poor, but they simply don't.
Not that you could not attempt to measure amplifiers for sound
quality, its simply the measurements are simply not good enough.
By a long way current measurements only indicate cheap amplifiers.
Advanced and complex measurements are not only expensive,
e.g. IMD, there is no concensus as to their meaning, whilst
things like THD+N are simple and cheap, and everyone knows
how it is derived, and all agree in a general concencus that
the lower it is the better generally, but not particularly.
I.e. valve amplifiers versus solid state THD+N is useless.
Its not going to change, THD+N is pretty useless comparing
solid state of various topologies with similar numbers, and
as ever, vanishing small THD+N figures are being chased.
Publishing of THD+N spectra would be a way forward,
but that isn't going to happen in the big wide world.
For sure armed with some serious measurement kit you will
only prove that a Krell seems to be seriously overpriced
compared to a Yamaha, that is because it is, in any
sensible reality, the Yamaha is far better VFM.
Is it just as good ? TBH for most systems probably.
Which is better ? The Krell probably, but not certain.
rgds, sreten.
FWIW I'd consider my favourite used budget amplifer,
the Pioneer A-300X, about £60 used, capable of being
used with any quality used speaker under about £1K.
FWIW a suitable quality CD player used is about £30.
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You will find that you are quite unable to dispute the relevant facts that I've brought to the discussion without deeper considerations. The prime fallacy in your statement is underpinned with your confusion as to the exact person who brought the document into publication and circulation. Upon re-reading my initial post herein, you will find I have made no special claims.
In a blind or ABX test, you would have a far less ignorant opinion. That fact that both cannels on your amp reproduce an identical mono audio signal stands testament to this.
No such thing has occurred, see above. Why someone would want to defend overpriced gear, which, in a scientifically backed listening test sounds no better than a more cost effective solution, escapes logic. Particularly, gear from a brand that selectively dismisses science and ABX testing when designing products that depend upon it for the determination of their exact function. Perhaps that would explain the brands longstanding history of being bereft of any CSA safety certification.
Comparing the compendium of misapprehensions and incorrect ideals in circuit design that have been brought forth and made visiable in defaulted patents and non-peer reviewed papers, to that of "genius" is yet another gross error in your judgment. We have the writings and reputations before us. This calls the brand's credibility into question among peers in the engineering field. And if that is the case, it would appear that he is not nearly as clever as you have portray him.
Rule of thumb - if you don't want people to further take notice of the contents, don't heap praise on the subjects.
I bring forth facts and documented information, all of which is backed by standard references in scientific journals and recognized regulatory authorities, not boutique sellers' agendas.Funny, nice piece of satire
dave
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ABX is only capable of showing 2 DUT are different. They are also not easy to execute properly, Most ABX tests, as executedm are not much use.
dave
Hi,
I think you'll find "brilliance" = USP. (Unique Selling Point.)
Its not the only way, and particularly not the typical way.
Good luck to his elbow, but there is no deep understanding
of optimum amplifiers in his approach, its very simplistic.
e.g. google "Death of Zen".
rgds, sreten.
I called my virtual aunt in the virtual heartland of America, and she offered this bit of wisdom . . .
"I am sure there is a good reason that this forum member believes what he does and furthermore, he may well be smarter. Go do something useful to improve your pathetic life instead, like washing that filthy kitchen floor or getting along with the neighbors."
OK -- advice accepted.
"I am sure there is a good reason that this forum member believes what he does and furthermore, he may well be smarter. Go do something useful to improve your pathetic life instead, like washing that filthy kitchen floor or getting along with the neighbors."
OK -- advice accepted.
That is somewhat omissive (don't take offense to that) of the salient mechanisms responsible for perception and preference, which includes expectation bias, confirmation bias, and the feedback mechanism of the cochlea's second row of hairs which serve as a high frequency augmentation. Adding low order harmonics can trigger this row of hairs into action, creating sound which is not present in the source. There are several combinations of tones that have this effect, and if any, tube amplifiers would be prime in stimulating such.
Absolutely, for it is dismissive of relative phase in harmonics and the proportions thereof. When they are present in analysis, however, they are more useful.
And there is no reason for the constant chasing, as we had incredibly low THD and wide bandwidth for decades. Where numbers are vanishingly small, they are of no relevance. What is inaudible bares no credence in the larger picture. From there, attention must be placed on the other non-linear and linear mode distortions outlined in my initial post. I don't need to tell you this though, because you are ahead of the game.
I would agree.
Care must be taken in all testing, but it is not nearly as difficult as implied in forums. What is important is that the switching mechanism be instantaneous and controlled by a force other than the subject, and that both devices be level matched. Several companies have produced products just for this purpose. If two amplifiers are indistinguishable, that is data. If two amplifiers are distinguishable, it has always been reflected in measurable data.
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