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#81
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Does anyone know of this challenge?
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#82
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#83
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Does anyone know of this challenge?
On 4/25/04 7:20 PM, in article jJXic.34947$aQ6.1879434@attbi_s51, "Stewart
Pinkerton" wrote: On 25 Apr 2004 14:15:44 GMT, Bromo wrote: The time and effort might be spent a bit more productively - perhaps trying to research and measure all sources of sonic imperfections not already known - pushing the forefront of hearing sciences, and so on. Actually, since we can already prove that dozens of amplifiers sound exactly the same below the clipping point, the time and effort would most definitely be better spent in selecting better speakers, and placing them in the best position in a well-sorted room. I agree that is a good use of an end user's time and money - but still - if people claim to hear a difference, it might be good to do the due diligence as a scientific sort to see if there is anything to these claims. Some have been made in the past that haven't helped, but some has been made that did. Of course, this would destroy 90% of 'high end' mythology - but perhaps the world would be a better place for that............ Mythology is bad - but I would be careful to discard the grain of truth with it. Even if the golden eared claimants were incorrect for the reasons *they* said - there might be something there important for sound reproduction that they didn't realize. |
#84
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Does anyone know of this challenge?
On 4/25/04 7:18 PM, in article xHXic.34068$w96.2423643@attbi_s54, "Nousaine"
wrote: Thiels are notorious for requiring a lo of current in the bass (and tend to be 3 Ohms) I have a Thiel CS-1.6 in house as we speak. While it does have a relatively low impedance there is nothing at all "tough" about the curve. You will find that if you have extra amps available at the bass end (I know from the 2.4's) the bass tightens right up and becomes very articulate. Given the bass cones are about 6" it might not make so much a difference, but the nearly 8" on the 2.4's sure did. Magnepans are -- magnepans and then to have a sub 5 Ohm load. Same as with the Theil. Indeed Magnepan is noted for claiming a nearly "resisitive" imdedance curve said to be easier to drive. Of course, that's BS (it has the typical resisitve, capacitive and inductive qualities just like all loudspeakers) but the curve is smooth and doesn't vary much over its operating bandwidth. Yes, but the Maggies are VERY revealing and tend to require a lot of current to sound their best. Think of it as driving a very very large cone. |
#85
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Does anyone know of this challenge?
"It won't be settled - you cannot prove a negative."
It has been suggested we don't prove anything, we fail to disprove. If we propose that amps of similar electrical specs will sound different and a listening test shows difference at a level of guessing, we haven't proven some other amp pair willn't pass the test, we have however shown that it fails to disprove the proposition that two such amps will sound alike. Do enough of these examples of failing to disprove and the confidence/potential that any future pars will sound different becomes so small that we have little interest/motivation to continue trying to disprove the proposition. That is the course that concensus building and the way scientific "truth" is formed. That is the power of the current benchmark in test results, we are now a good distance down the road that so many attempts have failed to disprove that we are quickly losing interest seeking those exceptions to the benchmark. |
#86
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Does anyone know of this challenge?
"However, the test is still meaningless in one sense. If I look at two
different speaker with very similar dispersion pattern and distorsion spec, but with completely different frequency response, both speaker would sound the same after correction with an EQ. Quite meaningless if the test purpose is to reveal whether there are audible differences between speakers. The need to EQ shows that there must be some flaws that has to be corrected, right?" Wrong, the eqed part is to weed out the folk who eqed their amp to create an obvious difference. Mr. clark reserves the right to eque his yamaha to match, thus any difference is now not one introduced by the challenger. It would be the rare amp these days that is not almost flat 20 - 20 k and for such an eque is not needed to counter the cheaters. If the cheater introduces a "flaw" he wants his amp to have the same "flaw" to put them on the same footing as before the cheater made his change. Any difference will then be not the now equal "flaw" but the inherent sound of the amps being compared. Remember, the test is not to find if one amp "sounds" better or good or anything but different. This is where the cheater does the eqe of his amp before the test to try to force that difference. |
#87
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Does anyone know of this challenge?
On 4/25/04 7:11 PM, in article WAXic.34897$aQ6.1874234@attbi_s51, "chung"
wrote: It won't be settled - you cannot prove a negative. So your real concern with any test is that it does not prove the negative? How about if you are the testee, and you cannot tell the difference. Is that good enough for *you*? Well. Given the speaker load that I am driving I am mostly concerned with the amount of Oomph I need in order to drive my speakers or those that I might choose. For instance, would the Yamaha that we are using as our baseline integrated be enough to sound good and power my Thiel 2.4's? As I have a lesser Yamaha, I doubt it. The contest does not have any value for me, then! |
#88
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Does anyone know of this challenge?
"The more I read and post in this thread, it seems to me that most of the
effort is trying to discredit a marketing department - and a few reviewers. What benefit would I, as a consumer, would get from this effort? Especially since it is designed not to help me find an amp that would match my speaker" You have got it. The test was designed to do exactly the above. It was to show that one can save money and stress knowing that a 1 k amp will sound no different then the 10 k amp found in the hi fi rags and floating on a sea of review ink. Your concern that an amp has enough current not to become unstable for a given spl is fine but not the reason for the test. The condition in the test that says the amps under test don't exceed stable limits is obvious, we don't want the 10 k amp wimping out on us so it sounds different for it's overloaded artifacts and thus easily identified. Your concern is a rather easy calculation done comparing lowest speaker load and the current limits of the amp, it is a universe away from and not relevent in the least to the reason for the test to exist. Your purchase concern is only about numbers, findd any two amps with similar numbers and you are home free and no difference in sound will be found. |
#89
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Does anyone know of this challenge?
"The contest is a silly endevour because of the various loads an amplifier
is asked to drive into - each speaker is different in impedance and the amount of current required in order to get a nice, flat response out of it (or a response the listener finds to his or her liking)." Irrelevant and silly on it's face, if we are going to evoke the "silly" metric into the discussion. In the test situation the speaker is an independent variable, as is the nature of tests where one tries to hold equal all but those things being tested. Even with the above truisms, the yamaha sounded no different then the pass labs. As I recall in the clark rules, any speaker was an option, any speaker and he still has his 10 k. On the silly scale your series of red herrings about forcing amps into current overload falls exactly where? The test is not to verfy the truism that amps can be driven into overload and will sound different when doing so. It is however the claim from the high end folk that the mega buck pass lab and the old few hundred yamaha will sound different because the former is high end and has inherent qualities, with other things being equal, there will be a "night and day" obvious sound easy as pie to identify. |
#90
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Does anyone know of this challenge?
"Sure, there might be people that fool themselves into thinking that there
is some ineffable difference between a Yamaha and a Halcro - and given the way this test is set up - it is skewed to prefer the Yamaha since the amplifiers aren't going to be driven into compression where any differences might be seen." No one cares about driving amps into the limits of their ability to provide current. Any two amps can be done so and is a empty exercise to do the obvious. The test is about driving speakers as is done in typical high end systems. Those who advocte "night and day" differences in sound don't even bdgin to drive their amps to be able to make their claims. They will make their claims with easy to drive speakers using amps whose current limits are rarely reached. The way you state your objection is a red herring for the test and the reasons it was created. The one rule that contains all your objections is the one that says amps are not to be driven above current limits, including the red hot latest thing the hi fi rags are all goo goo about and the latest example of "night and day" sound difference; which takes account of your "skewed" crack. That someone can mention that a load can potentially be found to exceed current limits is trivial and irrelevent. |
#91
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Does anyone know of this challenge?
"Yes - this makes this sort f test rather useless in information or
enlightenment. If I buy sme Maggie 3.6R's I has better get an amp with more cajones than the Yamaha integrated, for instance. If I get a Lowther horn speaker - I would do with a lot less power. I do not see how this "challenge" serves anyone but the ego of the "debunker"..." And whose ego is served by restatements of the truism that various speakers have various current demands at the extremes, which was never at issue? Whose ego is served by inserting red herrings into the discussion? Whose ego is served by arguing apples and oranges and distorting the reasons for the tests being done and concluding one's purchasing decisions have not therefore been served. And most important, whose ego is served if one can now conclude that the ego of another is not at issue either and can be ignored as irrelevant? |
#92
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Does anyone know of this challenge?
On 25 Apr 2004 19:22:27 GMT, Bromo wrote:
On 4/25/04 1:38 PM, in article 7ISic.32063$w96.2204064@attbi_s54, "Stewart Pinkerton" wrote: But, if you don't see it - feel free to take the "40Wpc into 8 Ohms at 1Khz" integrated and try to drive a Thiel 7.2.... No reasonable person would try such a thing. What is your point? The point I was making is that the "challenge" when hyped (a $10k "prize is hype in this case) might make an average consumer think that any old amp low, mid or hi-fi was capable of driving any old speaker because "they sound the same." And that would be true, except for a small number of 'high end' speakers, such as the Thiel you mention. Anyone with enough knowledge of the market to be considering purchase of one of these expensive 'audio nasties', might reasonably be presumed also to be aware of their drive requirements. If not, one would certainly hope that the sales droids at the speaker store would enlighten him! I have an AVR200 that used to drive my Thiel 2.4's - I now use a NADS200 to do the same - the articulation and bass response improved noticably due to the power - and according to the data sheet I had up to 90W available to do that (1kHz at 4Ohms was supposed to be 140W). The extra current really helped the sound I figure when driving that speaker. Made a difference, when I expected very little. I'm sure it did, but this has nothing to do with the claims made by so-called 'high end' amp manufacturers, or their partners in crime - the ragazine reviewers. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#93
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Does anyone know of this challenge?
On Sun, 25 Apr 2004 23:40:59 GMT, Bromo wrote:
On 4/25/04 7:20 PM, in article jJXic.34947$aQ6.1879434@attbi_s51, "Stewart Pinkerton" wrote: On 25 Apr 2004 14:15:44 GMT, Bromo wrote: The time and effort might be spent a bit more productively - perhaps trying to research and measure all sources of sonic imperfections not already known - pushing the forefront of hearing sciences, and so on. Actually, since we can already prove that dozens of amplifiers sound exactly the same below the clipping point, the time and effort would most definitely be better spent in selecting better speakers, and placing them in the best position in a well-sorted room. I agree that is a good use of an end user's time and money - but still - if people claim to hear a difference, it might be good to do the due diligence as a scientific sort to see if there is anything to these claims. Some have been made in the past that haven't helped, but some has been made that did. That is the exact purpose of the various amp and cable challenges. Of course, this would destroy 90% of 'high end' mythology - but perhaps the world would be a better place for that............ Mythology is bad - but I would be careful to discard the grain of truth with it. Even if the golden eared claimants were incorrect for the reasons *they* said - there might be something there important for sound reproduction that they didn't realize. Interesting that, despite your apparent (and quite reasonable) standpoint that adequate power is all that matters, you are *still* buying into the notion that there may be some 'magical' ingredient that we just don't know about. The real truth is, that P.T. Barnum is alive and well................ -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#94
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Does anyone know of this challenge?
On 25 Apr 2004 23:44:29 GMT, Bromo wrote:
Yes, but the Maggies are VERY revealing and tend to require a lot of current to sound their best. Think of it as driving a very very large cone. It's no different electromechanically from driving a very small cone, only the dispersion pattern varies. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#96
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Does anyone know of this challenge?
"Nousaine" wrote in message
news:xHXic.34068$w96.2423643@attbi_s54... Bromo wrote: On 4/24/04 1:03 PM, in article P5xic.20708$aQ6.1263449@attbi_s51, "Nousaine" wrote: snip It is understood by anyone that if you do not feed the speaker with enough power, it won't sound good - too much power, and you will blow it out. Conventional measurements should indicate if the speaker is likely to be suitable, but to think we understand hearing and the processing our brains go through to change pressure to sound to make it an end game is pure arrogance to me! IMO if there were anything to amp sound that is not readily observable with traditional measurements and methods then the Richard Clark Challenge should have brought it to light. Would you please indicate where in Stereophile's set of conventional measurement the "microphony" test resides that clearly shows microphony as the reason tube amps are preferred by many audiophiles, as objectivists love to proclaim loudly and often here. |
#97
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Does anyone know of this challenge?
"Well. Given the speaker load that I am driving I am mostly concerned
with the amount of Oomph I need in order to drive my speakers or those that I might choose. For instance, would the Yamaha that we are using as our baseline integrated be enough to sound good and power my Thiel 2.4's? As I have a lesser Yamaha, I doubt it. The contest does not have any value for me, then!" Irrelevant, trivial, apples and oranges with regard to the reasons the test exists; and especially so with regard to your needs. If you are interested design a test to serve your needs, don't tap dance about rhetorically trying to shoehorn your needs into a test which never was about your needs. Needs and purchasing decisioons etc. were never at issue, only the claims of those saying there are inherent obvious "night and day" easily heard differences between amps with similar electrical properties. Mr. clark and others have set up a situation where those claims can be fairly evaluated in a repeatabvle manner. Your test of needs will have to await another day. |
#98
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#99
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Does anyone know of this challenge?
Bromo wrote in message
... I am looking at a Halcro Ad on this month's Stereophile (pg. 15, May '04) right now...If you measure any deviation in the RIAA curve...you have caught them in a lie and you can feel confident in debunking them. You can my measurement of the Halcro dm10's RIAA error in our on-line review reprint: http://www.stereophile.com/amplifica...ro/index5.html. The deviation from the specificed curve is indeed minimal, other than the incorporation of the IEC-specified low-frequency rolloff. John Atkinson Editor, Stereophile |
#101
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Does anyone know of this challenge?
On 4/26/04 1:34 PM, in article zKbjc.41838$IW1.2009846@attbi_s52, "Stewart
Pinkerton" wrote: I agree that is a good use of an end user's time and money - but still - if people claim to hear a difference, it might be good to do the due diligence as a scientific sort to see if there is anything to these claims. Some have been made in the past that haven't helped, but some has been made that did. That is the exact purpose of the various amp and cable challenges. The problem is that it is *not* due diligence, but grandstanding rather loudly ! Real due diligence wopuld involve getting the amplifiers in question and doing both double blind testing with a variety of speaker systems and a variety of sonic and electrical measurements. Not some silly $10k "challenge" |
#102
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#104
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Does anyone know of this challenge?
On 4/26/04 8:26 PM, in article UMhjc.26847$cF6.1179523@attbi_s04, "Nousaine"
wrote: Stewart Pinkerton wrote: ...snip to content...... On 25 Apr 2004 19:22:27 GMT, Bromo wrote: The point I was making is that the "challenge" when hyped (a $10k "prize is hype in this case) might make an average consumer think that any old amp low, mid or hi-fi was capable of driving any old speaker because "they sound the same." And that would be true, except for a small number of 'high end' speakers, such as the Thiel you mention. Anyone with enough knowledge of the market to be considering purchase of one of these expensive 'audio nasties', might reasonably be presumed also to be aware of their drive requirements. If not, one would certainly hope that the sales droids at the speaker store would enlighten him! A good salesman would never pass up on an opportunity to sell an amplifier with every speaker purchase necessary or not :-) Actually these guys knew that I wouldn't pay a ton aside from the speakers so helped me pick out some low to moderately priced electronics to help drive them. |
#106
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Does anyone know of this challenge?
much snipped...
We've done enough testing of specific claims to have laid that idea to rest. There is no underground grain-of-truth resting just below the surface. If there were then someone, somewhere would have stumbled on it over the past 30 years of searching. Tom, I agree that there is not much that differs amps during music listening and using 99.9% of loudspeakers of the market, and standard DBT testing. But if one wants to find out any putative difference, the test methodology needs to be the most sensitive around. The before/after listening tests are far more sensitive that just comparing two amps A/B, since you are comparing the amp with a bypass cable (the "before" signal). I've posted the link befo http://www.sonicdesign.se/amptest.htm I am not saying that there will be audible differences when comparing the traditional DBT way, but putting things to "rest" does not mean that there are differences, explained by physical terms, that can be judged to be significant different. It will, however, have probably have little practical meaning for the user. It can also be a preference to have an amp where the spec are far below the audible limit thereby it will warrant such a market. (I am not talking about expensive amps which have poor spec here, but those having high-end spec and thus in general more expensive.) T |
#107
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Does anyone know of this challenge?
"The problem is that it is *not* due diligence, but grandstanding rather
loudly ! Real due diligence wopuld involve getting the amplifiers in question and doing both double blind testing with a variety of speaker systems and a variety of sonic and electrical measurements. Not some silly $10k "challenge"" Ah, the silly metric again. If no difference can be heard any electrical difference is irrelevant by definition. The noise level on this topic has always been highish on the part of all. The cash is indeed relevant in an intresting sort of way. One metric, indeed silly, is the compulsive use of price as some reason to think an amp or wire will "sound" accordingly. To counter with a cash motivation is an ironic balancing of the scales, a simple purgative of toxic self definition and a form of conspicuious consumption. The benchmark now in place has been done by the sum of tests with all manner of gear. |
#108
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Does anyone know of this challenge?
On Mon, 26 Apr 2004 23:54:59 GMT, Bromo wrote:
On 4/26/04 1:34 PM, in article zKbjc.41838$IW1.2009846@attbi_s52, "Stewart Pinkerton" wrote: I agree that is a good use of an end user's time and money - but still - if people claim to hear a difference, it might be good to do the due diligence as a scientific sort to see if there is anything to these claims. Some have been made in the past that haven't helped, but some has been made that did. That is the exact purpose of the various amp and cable challenges. The problem is that it is *not* due diligence, but grandstanding rather loudly ! Real due diligence wopuld involve getting the amplifiers in question and doing both double blind testing with a variety of speaker systems and a variety of sonic and electrical measurements. Not some silly $10k "challenge" The choice of speaker system is free to the challenger, so what's your problem? BTW, electrical measurements are irrelevant, we're talking about *sound* quality here. Once a difference in *sound* has been established, it's easy enough to pin it down, because it is IME *always* tied to a gross technical problem, nothing at all subtle! -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#109
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Does anyone know of this challenge?
(Thomas A) wrote:
much snipped... We've done enough testing of specific claims to have laid that idea to rest. There is no underground grain-of-truth resting just below the surface. If there were then someone, somewhere would have stumbled on it over the past 30 years of searching. Tom, I agree that there is not much that differs amps during music listening and using 99.9% of loudspeakers of the market, and standard DBT testing. But if one wants to find out any putative difference, the test methodology needs to be the most sensitive around. The before/after listening tests are far more sensitive that just comparing two amps A/B, since you are comparing the amp with a bypass cable (the "before" signal). I've posted the link befo http://www.sonicdesign.se/amptest.htm I am not saying that there will be audible differences when comparing the traditional DBT way, but putting things to "rest" does not mean that there are differences, explained by physical terms, that can be judged to be significant different. It will, however, have probably have little practical meaning for the user. It can also be a preference to have an amp where the spec are far below the audible limit thereby it will warrant such a market. (I am not talking about expensive amps which have poor spec here, but those having high-end spec and thus in general more expensive.) T The wire bypass test is a good idea. In fact, Arny Kreuger's pcabx is precisely that. But the site's "data" is simply a statement. But taken in context wouldn't you say that all the cable-swap and switched test results would tend to show that if it is true as the site claims that if nearly 90% of amplifiers are not straight wires with gain into his simulayed load they must nearly universally have the same errors. |
#110
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Does anyone know of this challenge?
"Nousaine" wrote in message
... "Harry Lavo" wrote: "Nousaine" wrote in message news:xHXic.34068$w96.2423643@attbi_s54... Bromo wrote: On 4/24/04 1:03 PM, in article P5xic.20708$aQ6.1263449@attbi_s51, "Nousaine" wrote: snip It is understood by anyone that if you do not feed the speaker with enough power, it won't sound good - too much power, and you will blow it out. Conventional measurements should indicate if the speaker is likely to be suitable, but to think we understand hearing and the processing our brains go through to change pressure to sound to make it an end game is pure arrogance to me! IMO if there were anything to amp sound that is not readily observable with traditional measurements and methods then the Richard Clark Challenge should have brought it to light. Would you please indicate where in Stereophile's set of conventional measurement the "microphony" test resides that clearly shows microphony as the reason tube amps are preferred by many audiophiles, as objectivists love to proclaim loudly and often here. It would seem to me that the frequency response anomalies that come with high-output impedance amplifiers completely describe any audible differences in tubed amplifiers. As far as the microphony "issue" it seems to me like one you just made up yourself. Poppycock (to quote one of your own)!! I have never mentioned this issue before.. nor do I believe it. But it has been raised here regularly by certain objectivists....I will not name names lest I be forced to spend my sleep time looking for the exact quotes, but I think we know who they are .... or at least they do. So if standard specs tell it all, I want to know which specs they (and you, since you made the statement) would have me look at. Moreover, I and those preferring tubes usually are speaking of good old push-pull tubed amps with reasonably low output impedances. Not the SET's that you guys love to whup up on. |
#111
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#112
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Does anyone know of this challenge?
Regarding the test discussed at:
http://www.sonicdesign.se/amptest.htm "This will force the amplifier to deliver a strongly distorted current, just like with a normal loudspeaker, in order to deliver a correct voltage. This is a very hard task for many amplifiers!" An amp driven into it's nonlinear range can have audible artifacts. What have we learned that is new from the article? The test, if I'm understanding it correctly, is driving a fake speaker load and tapping of the output, providing the above observation. If we introduce some element into the chain that causes the above, and any amp can in principle be made to do so, and tap the signal from that element; what have we learned? Only if in the normal configuration does all the distortions usually created by current unstability rise above an audible threshold will it be percieved so to be able to identify it from another amp. Potential to cause the above is only a concern if a known difficult load is to be used. This is easy to anticipate and getting an amp with enough current capacity no problem. To pick an example, if the middle of the line adcom doesn't do it, larger amps in the line should be purchased instead. It would be useful for such as the test to be done as part of an amp review, I refuse to use "audition" for what is done, to see if a particular amp might be prone to current problems, but the solution is still the same and the latest wiz bang "night and day" pick of the month is not it. |
#113
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#114
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(Nousaine) wrote in message news:_0Bjc.31128$0u6.5483536@attbi_s03...
(Thomas A) wrote: much snipped... We've done enough testing of specific claims to have laid that idea to rest. There is no underground grain-of-truth resting just below the surface. If there were then someone, somewhere would have stumbled on it over the past 30 years of searching. Tom, I agree that there is not much that differs amps during music listening and using 99.9% of loudspeakers of the market, and standard DBT testing. But if one wants to find out any putative difference, the test methodology needs to be the most sensitive around. The before/after listening tests are far more sensitive that just comparing two amps A/B, since you are comparing the amp with a bypass cable (the "before" signal). I've posted the link befo http://www.sonicdesign.se/amptest.htm I am not saying that there will be audible differences when comparing the traditional DBT way, but putting things to "rest" does not mean that there are differences, explained by physical terms, that can be judged to be significant different. It will, however, have probably have little practical meaning for the user. It can also be a preference to have an amp where the spec are far below the audible limit thereby it will warrant such a market. (I am not talking about expensive amps which have poor spec here, but those having high-end spec and thus in general more expensive.) T The wire bypass test is a good idea. In fact, Arny Kreuger's pcabx is precisely that. But the site's "data" is simply a statement. But taken in context wouldn't you say that all the cable-swap and switched test results would tend to show that if it is true as the site claims that if nearly 90% of amplifiers are not straight wires with gain into his simulayed load they must nearly universally have the same errors. Tom, I don't think they are saying that every amp has the same errors, but they can probably be divided into a few "groups". I've not read all the different tests that have been conducted during the years, but usually, the amps coming up to be transparent (or very close) are e.g. NAD 208 THX and Rotel RB 1090. The recommended list of equipment is he http://www.lts.a.se/teknik/rekommenderat.html Although it is in Swedish it is probably not difficult to understand which components that are "recommended". T |
#115
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On 27 Apr 2004 23:24:07 GMT, "Harry Lavo" wrote:
"Nousaine" wrote in message ... As far as the microphony "issue" it seems to me like one you just made up yourself. Poppycock (to quote one of your own)!! I have never mentioned this issue before.. nor do I believe it. But it has been raised here regularly by certain objectivists....I will not name names lest I be forced to spend my sleep time looking for the exact quotes, but I think we know who they are .... or at least they do. I am one of them. I have heard definite microphony effects in SET amps - easily proved by locating the amps in my study (from where I'm typing this), which is through a brick wall from the listening room, but has a baffled cable duct for 'PC sound' and separates the amp from the acoustic impact of the speakers. The traditional placing of monobloc SET amps behind the speakers turns out to be a *bad* idea! The same is even more true of tubed phono stages. Moreover, I and those preferring tubes usually are speaking of good old push-pull tubed amps with reasonably low output impedances. Not the SET's that you guys love to whup up on. Indeed, I'd agree that a top-class PP tube amp like the ARC VT100 or C-J Premier Eight is indistinguishable from any good SS amp, which is kinda interesting, given all the claims for 'tube magic', which seems to go away as the tube amp gets better....................... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#116
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Does anyone know of this challenge?
On 27 Apr 2004 23:32:37 GMT, (S888Wheel) wrote:
From: Stewart Pinkerton Date: 4/27/2004 9:55 AM Pacific Standard Time Message-id: Hfwjc.30312$0u6.5306584@attbi_s03 The choice of speaker system is free to the challenger, so what's your problem? BTW, electrical measurements are irrelevant, we're talking about *sound* quality here. Once a difference in *sound* has been established, it's easy enough to pin it down, because it is IME *always* tied to a gross technical problem, nothing at all subtle! Given the fact that you have reported hearing differences between certain models of amplifiers in your own blind tests, why don't you take the challenge and collect the 10K? Because the differences were down to easily traceable technical faults, and while I *could* build an amp which would both meet the criteria and be instantly identifiable, it would not be within the *spirit* of the challenge. It would not be a 'superior' high end amp, but would have some quite horrific colourations (or a very high noise floor) which are not covered in the entry criteria. I don't see the point of cheating for its own sake on such a test.......... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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Does anyone know of this challenge?
wrote in message ...
Regarding the test discussed at: http://www.sonicdesign.se/amptest.htm "This will force the amplifier to deliver a strongly distorted current, just like with a normal loudspeaker, in order to deliver a correct voltage. This is a very hard task for many amplifiers!" An amp driven into it's nonlinear range can have audible artifacts. What have we learned that is new from the article? The test, if I'm understanding it correctly, is driving a fake speaker load and tapping of the output, providing the above observation. If we introduce some element into the chain that causes the above, and any amp can in principle be made to do so, and tap the signal from that element; what have we learned? Only if in the normal configuration does all the distortions usually created by current unstability rise above an audible threshold will it be percieved so to be able to identify it from another amp. Potential to cause the above is only a concern if a known difficult load is to be used. This is easy to anticipate and getting an amp with enough current capacity no problem. To pick an example, if the middle of the line adcom doesn't do it, larger amps in the line should be purchased instead. It would be useful for such as the test to be done as part of an amp review, I refuse to use "audition" for what is done, to see if a particular amp might be prone to current problems, but the solution is still the same and the latest wiz bang "night and day" pick of the month is not it. Note that this not a test, but a test method. All tests made using this method is published elsewhere and, unfortunately, in Swedish. Except for compression artefacts at high outputs, there are frequency response deviations that in some cases shows up as different in the blind tests. Also, the reviewer is free to set the criteria for a "recommended amp", e.g. "it should be able to recreate the signal in 99.9% of the speakers in the market with no or little compression of musc playing realistic levels" (which can be quite high if you want to simulate the SPL of a drum set . As stated in their recommendation of the NAD 208 THX amp: "Able to reproduce signals with no audible artefacts up to 250W, and with small audible artefacts up to 600 W" Now, what new can be gained by such a before/after test? Well, with respect to frequency response deviations, with amp with similar roll off in the low en (e.g. -3 dB at 7 Hz) may not be different in a standard A/B test, but when compared to a cable only, it might. So the advantage of a before/after listening test is that it's more sensitive for colorations. This goes for all types of possible audible colorations. So my point is that if one really wants to find out audible (or tactile) differences, the most sensitive test method must be used. Thomas |
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Does anyone know of this challenge?
"Stewart Pinkerton" wrote in message
news:w8Rjc.6132$lz5.814689@attbi_s53... On 27 Apr 2004 23:24:07 GMT, "Harry Lavo" wrote: "Nousaine" wrote in message ... As far as the microphony "issue" it seems to me like one you just made up yourself. Poppycock (to quote one of your own)!! I have never mentioned this issue before.. nor do I believe it. But it has been raised here regularly by certain objectivists....I will not name names lest I be forced to spend my sleep time looking for the exact quotes, but I think we know who they are .... or at least they do. I am one of them. I have heard definite microphony effects in SET amps - easily proved by locating the amps in my study (from where I'm typing this), which is through a brick wall from the listening room, but has a baffled cable duct for 'PC sound' and separates the amp from the acoustic impact of the speakers. The traditional placing of monobloc SET amps behind the speakers turns out to be a *bad* idea! The same is even more true of tubed phono stages. Moreover, I and those preferring tubes usually are speaking of good old push-pull tubed amps with reasonably low output impedances. Not the SET's that you guys love to whup up on. Indeed, I'd agree that a top-class PP tube amp like the ARC VT100 or C-J Premier Eight is indistinguishable from any good SS amp, which is kinda interesting, given all the claims for 'tube magic', which seems to go away as the tube amp gets better....................... And what audiophiles do you know who have bought ARC VT100 or C-J Premier Eights (among the most popular of mainstream tube amps) that thought they lacked "tube magic"? |
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Does anyone know of this challenge?
(Thomas A) wrote:
(Nousaine) wrote in message news:_0Bjc.31128$0u6.5483536@attbi_s03... (Thomas A) wrote: much snipped... We've done enough testing of specific claims to have laid that idea to rest. There is no underground grain-of-truth resting just below the surface. If there were then someone, somewhere would have stumbled on it over the past 30 years of searching. Tom, I agree that there is not much that differs amps during music listening and using 99.9% of loudspeakers of the market, and standard DBT testing. But if one wants to find out any putative difference, the test methodology needs to be the most sensitive around. The before/after listening tests are far more sensitive that just comparing two amps A/B, since you are comparing the amp with a bypass cable (the "before" signal). I've posted the link befo http://www.sonicdesign.se/amptest.htm I am not saying that there will be audible differences when comparing the traditional DBT way, but putting things to "rest" does not mean that there are differences, explained by physical terms, that can be judged to be significant different. It will, however, have probably have little practical meaning for the user. It can also be a preference to have an amp where the spec are far below the audible limit thereby it will warrant such a market. (I am not talking about expensive amps which have poor spec here, but those having high-end spec and thus in general more expensive.) T The wire bypass test is a good idea. In fact, Arny Kreuger's pcabx is precisely that. But the site's "data" is simply a statement. But taken in context wouldn't you say that all the cable-swap and switched test results would tend to show that if it is true as the site claims that if nearly 90% of amplifiers are not straight wires with gain into his simulayed load they must nearly universally have the same errors. Tom, I don't think they are saying that every amp has the same errors, but they can probably be divided into a few "groups". I've not read all the different tests that have been conducted during the years, but usually, the amps coming up to be transparent (or very close) are e.g. NAD 208 THX and Rotel RB 1090. The recommended list of equipment is he http://www.lts.a.se/teknik/rekommenderat.html Although it is in Swedish it is probably not difficult to understand which components that are "recommended". T Sorry I wasn't a bit more clear. If, as this sire claimed, 8 of 9 amplifiers could be distinguished from a straight wire when their output was played through a 2nd amplifier then amplifiers 'different' sounding than a piece of wire are common. However, there have been a couple dozen bias-controlled listening tests of amplifiers which have only found amplifiers with a lack of competence (frequency response, overload or other operating errors) to sound different from one another. So putting these two data set together I would think that all those amplifiers that sound different from a piece of wire (90%) but do not show up as being different sounding from each other in other tests must have errors with enough similarity that they sound like each other even if they don't sound identical to a piece of wire. |
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Does anyone know of this challenge?
On 4/28/04 12:41 PM, in article w8Rjc.6132$lz5.814689@attbi_s53, "Stewart
Pinkerton" wrote: Moreover, I and those preferring tubes usually are speaking of good old push-pull tubed amps with reasonably low output impedances. Not the SET's that you guys love to whup up on. Indeed, I'd agree that a top-class PP tube amp like the ARC VT100 or C-J Premier Eight is indistinguishable from any good SS amp, which is kinda interesting, given all the claims for 'tube magic', which seems to go away as the tube amp gets better....................... What about the slew rate of a tube - isn't it slower than most non-switch mode solid state? |
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