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#41
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On 17 Oct 2004 14:40:29 GMT, Tat Chan
wrote: Stewart Pinkerton wrote: On 16 Oct 2004 15:09:20 GMT, Tat Chan wrote: Stewart Pinkerton wrote: It depends. The parts for my own passive controller cost more than $800, being a Penny&Giles studio pot and a bunch of Pickering Ruthenium-tipped relays, with Neutrik gold-clad XLR connectors and a very smooth power supply (for the relays). OTOH, I can't see where the sales price comes from when it's just a box with an Elma Switch and an Alps pot, total parts cost not exceeding $100, more like $50 in OEM quantity. Cough! Cough! $800? If I changed my name to Mark Levinson, I could no doubt charge $8,000 for it............. is that with or without a tube output stage? Nope, but including 45 kilos of laser-cut magnesium alloy which doesn't actually do anything.................... I hope it comes with a remote control for that amount of money ... Of course it does! Voice controlled, even: "Anne, turn the volume up a bit"...................... Oh great, voice recognition software built in as well ... Does it ever go "I'm sorry Dave, I'm afraid I can't do that?" No, I have upgraded to the JCN 9000, which fixed those bugs. I also have a magic washing basket - you throw in dirty clothes, and they reappear a few days later in your clothes drawers, washed and pressed! Ah, so you got one of those Wash Iron Food Etc (WIFE) contraptions then? Do they come with a 3 year warranty and 30 day money back gurantee? No, they come with a lifetime warranty and take all your money...... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#43
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Robert C. Lang wrote:
Stewart Pinkerton wrote in message ... On 14 Oct 2004 23:47:08 GMT, (Robert C. Lang) wrote: Resistor based passive designs have inherent issues that must be tamed to bring the passive closer to the music. The primary problem with typical high end resistors, including many of the lower cost Vishay resistors is brightness (high frequency distortion). Excuse me? Do you have *any* evidence for this extraordinary claim? I have run sweeps on many resistors, and I find no evidence whatsoever of *any* distortion products on any of the better types (wirewound, metal-film or bulk metal), below 100kHz and down to -140dB below a 10 volt rms drive signal. Aside from some parasitic inductance and capacitance, which of course does not introduce nonlinear distortion, merely frequency response effects, modern resistors simply don't cause problems IME - and I was looking for linearity and frequency response *way* beyond what you'd need for domestic audio! I will defer to your empirical conclusions based on your tests. I should have clarified my response so as to not elevate it to a claim. My information came directly from two (not one) respected pre amp designers, both whom could clearly be biased toward materials they use for their products. I will, however, talk to one of the designers about *his* claim and report back to the group. But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? I realize that there is much more to a passive (such as design implementation) than merely its resistors. How about the choice of resistor values? Too low, and you risk loading the sources, and too high, you have too much high frequency droop and noise. The biggest problem with passive preamp is that (a) there is no voltage gain and buffering, and (b) the capacitance of the cable at the output could affect the frequency response. Also, what parts *can* and *do* make a measurable/audible difference? Matching of left and right channels, by using accurate resistors. Quality of the switches/relays. You mentioned that your passive had $800 worth of parts. Why does your passive sound superior to others that you have heard? He actually did not say that. Could the designer have gotten away with parts that cost substanially less with out an audible penalty? I guess what I am asking is if key parts such as resistors don't make a difference (I'm not trying to put words in your mouth) then what is the point of using anything but the cheapest? Tolerances. Good switches are more expensive. Aesthetics (mechanical design). That's certainly true, and can make some switched attenuators very expensive indeed. But will they sound better? Better left-right tracking is good. |
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#44
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Georg Grosz wrote:
If the two preamps were given a fair double blind test, and sounded different, one of them would probably be an incompetent design. I wish I had take more Philosophy classes that worked through logical thinking. Somehow when I make a post asking "Do preamps sound alike?" and there are a number of answers like this I imagine myself doing a comparison of two preamps, hearing a difference, then asking myself "Which one is the incompetent one. Let's check the specs. Hmmm, both have excellent specs. Could it be that both of them are incompetent in different ways?" At that point to reach a conclusion I would either have to begin conducting technical research beyond my education or just deciding I like one better than the other, and start comparing it to others until I find the one I like best. At least I am qualified to do that. But then I have just thrown objectivity out the window. Or should I read audiophile magazines that have access to more preamps than I will ever be able to audition? No, can't do that they are subjective. But then so am I. Must be objective, but don't have the tools. I know, I'll post on RAHE. No, I did that and the results were definitely mixed. I must restart my train of thought as I seems to have acquired a circular track. Where is the exit? Wylie Williams |
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#45
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Wylie Williams wrote:
Georg Grosz wrote: If the two preamps were given a fair double blind test, and sounded different, one of them would probably be an incompetent design. I wish I had take more Philosophy classes that worked through logical thinking. Somehow when I make a post asking "Do preamps sound alike?" and there are a number of answers like this I imagine myself doing a comparison of two preamps, hearing a difference, then asking myself "Which one is the incompetent one. Let's check the specs. Hmmm, both have excellent specs. Could it be that both of them are incompetent in different ways?" At that point to reach a conclusion I would either have to begin conducting technical research beyond my education or just deciding I like one better than the other, and start comparing it to others until I find the one I like best. At least I am qualified to do that. But then I have just thrown objectivity out the window. Or should I read audiophile magazines that have access to more preamps than I will ever be able to audition? No, can't do that they are subjective. But then so am I. Must be objective, but don't have the tools. I know, I'll post on RAHE. No, I did that and the results were definitely mixed. I must restart my train of thought as I seems to have acquired a circular track. Where is the exit? Wylie Williams So you don't like (some of) the answers that you received? Where is the circular track? Let me try to summarize the answers for you: (1) Some people believe that preamps sound very different from one another. (2) Some people believe that preamps should sound alike, but due to implementation issues, some sound different (due to poor designs). (3) Some people think that they sound alike under DBT conditions. (4) Some people believe that phono preamps can sound different. So, why are you not happy with the answers? Again, where is the circular track? By the way, if you ask the question "Do all cables sound alike?", you would probably get the same answers. |
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#46
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Stewart Pinkerton wrote:
On 17 Oct 2004 14:40:29 GMT, Tat Chan wrote: Stewart Pinkerton wrote: is that with or without a tube output stage? Nope, but including 45 kilos of laser-cut magnesium alloy which doesn't actually do anything.................... would make a handy door stop if nothing else Of course it does! Voice controlled, even: "Anne, turn the volume up a bit"...................... Oh great, voice recognition software built in as well ... Does it ever go "I'm sorry Dave, I'm afraid I can't do that?" No, I have upgraded to the JCN 9000, which fixed those bugs. JCN 9000? |
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#47
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Wylie Williams wrote:
Georg Grosz wrote: If the two preamps were given a fair double blind test, and sounded different, one of them would probably be an incompetent design. I wish I had take more Philosophy classes that worked through logical thinking. Somehow when I make a post asking "Do preamps sound alike?" and there are a number of answers like this I imagine myself doing a comparison of two preamps, hearing a difference, then asking myself "Which one is the incompetent one. Let's check the specs. Hmmm, both have excellent specs. Could it be that both of them are incompetent in different ways?" Dude, what else is a pre-amp meant to do other than act as a source selector and volume control? As such, a pre-amp should be nothing more than a connection (maybe with some gain) to the power amp and as such have no distinct sound of its own. |
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#48
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#49
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Tat Chan wrote:
Stewart Pinkerton wrote: On 17 Oct 2004 14:40:29 GMT, Tat Chan wrote: Stewart Pinkerton wrote: is that with or without a tube output stage? Nope, but including 45 kilos of laser-cut magnesium alloy which doesn't actually do anything.................... would make a handy door stop if nothing else Of course it does! Voice controlled, even: "Anne, turn the volume up a bit"...................... Oh great, voice recognition software built in as well ... Does it ever go "I'm sorry Dave, I'm afraid I can't do that?" No, I have upgraded to the JCN 9000, which fixed those bugs. JCN 9000? Whoops, I think I have answered my own question. HAL -- IBM --- JCN |
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#50
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Wylie Williams wrote in message ...
Georg Grosz wrote: If the two preamps were given a fair double blind test, and sounded different, one of them would probably be an incompetent design. I wish I had take more Philosophy classes that worked through logical thinking. Somehow when I make a post asking "Do preamps sound alike?" and there are a number of answers like this I imagine myself doing a comparison of two preamps, hearing a difference, then asking myself "Which one is the incompetent one. The first question should be, "Have I listened to these in a way that allows me to be SURE that I am really hearing a difference, and not merely imagining one (or really hearing a dfference that's the result of a level-mismatch, rather than any flaw in either unit)?" That's probably your answer. Let's check the specs. Hmmm, both have excellent specs. Could it be that both of them are incompetent in different ways?" Or could it be that the spec sheets do not accurately reflect each component's performance? At that point to reach a conclusion I would either have to begin conducting technical research beyond my education or just deciding I like one better than the other, and start comparing it to others until I find the one I like best. At least I am qualified to do that. But then I have just thrown objectivity out the window. Or should I read audiophile magazines that have access to more preamps than I will ever be able to audition? No, can't do that they are subjective. But then so am I. Must be objective, but don't have the tools. Sure you do. Anyone can do an objective listening comparison, if they care to go to the trouble. I know, I'll post on RAHE. No, I did that and the results were definitely mixed. I must restart my train of thought as I seems to have acquired a circular track. Where is the exit? The exit lies in learning to conduct meaningful listening comparisons. Or in simply deciding to believe the subjectivists' story. Take your pick. bob |
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#51
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#52
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The biggest problem with passive preamp is that (a) there is no voltage
gain and buffering, and (b) the capacitance of the cable at the output could affect the frequency response. Not only the cable capacitance. Many amplifiers use a shunt capacitor (220pF, 390pF, etc) across the input to suppress high frequency noise. This is very significant when using resistor values higher than 10KOhm. |
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#53
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#54
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While we´re on this topic, I'm wondering if anyone has information
about an old Parasound preamp -- the PR200. Is it a John Curl design? Is it as nice as the later Parasounds? Also looking for info on the old Parasound PA260 Power amp... same questions. These models don´t even show up on the Parasound web site (which has info on a lot of discontinued stuff.) |
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#55
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Stewart Pinkerton wrote in message ...
.. But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? Has it indeed? Do you have any *evidence* for this extraordinary claim? Please see comments in my post to this thread dated October 12 relative to my experiences with the Audible Illusions 3A. I guess what I am asking is if key parts such as resistors don't make a difference (I'm not trying to put words in your mouth) then what is the point of using anything but the cheapest? None at all, sonically. Of course, a P&G pot has a very smooth action and will last 'forever', as will the ruthenium-tipped relays. Using parts that will increase the longevity and reliability of the unit is as valid a reason as any for investing in more expensive parts. Given that there are no sonic advantages in an high-end and expensive line stage is the reliability factor the sole reason you spent the extra bucks? That's certainly true, and can make some switched attenuators very expensive indeed. But will they sound better? Not in my experience, and I've built attenuators using Vishay S102s, which is as good as it gets technically. Do expensive Vishay S102s (which is what my linestage utilizes) last longer and or more reliable than the lower cost cousins? If not, why pay the vastly increased cost? Robert C. Lang |
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#56
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Robert C. Lang wrote:
Stewart Pinkerton wrote in message ... . But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? Has it indeed? Do you have any *evidence* for this extraordinary claim? Please see comments in my post to this thread dated October 12 relative to my experiences with the Audible Illusions 3A. What you posted was a sighted preference, hardly evidence. If you can show that the Audible Illusions 3A has *measureably* better performance, then you have something to start from. Even then, the better performance could be due to better choice of resistor values, or a host of other possibilities like better matching, better switching, etc., rather than using expensive resistors vs not-so-expensive resistors I guess what I am asking is if key parts such as resistors don't make a difference (I'm not trying to put words in your mouth) then what is the point of using anything but the cheapest? None at all, sonically. Of course, a P&G pot has a very smooth action and will last 'forever', as will the ruthenium-tipped relays. Using parts that will increase the longevity and reliability of the unit is as valid a reason as any for investing in more expensive parts. Given that there are no sonic advantages in an high-end and expensive line stage is the reliability factor the sole reason you spent the extra bucks? I think he likes the action of the P&G potentiometers. And perhaps the much finer control (than resistive attenuators). That's certainly true, and can make some switched attenuators very expensive indeed. But will they sound better? Not in my experience, and I've built attenuators using Vishay S102s, which is as good as it gets technically. Do expensive Vishay S102s (which is what my linestage utilizes) last longer and or more reliable than the lower cost cousins? If not, why pay the vastly increased cost? No reason to. The Vishay s102 family is designed for ultra-high accuracy applications. It has excellent temperature stabililty and could be ordered in matched pairs. Those are very good attributes for certain applications like discrete DAC's, but overkill for audio applications. Reliability/longevity is not a reason for using these expensive resistors. I will be willing to bet that if you were to replace all the s102 resistors with cheaper metal film resistors of the same value, you could not tell any difference. |
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#57
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Chung wrote in message ...
Robert C. Lang wrote: Stewart Pinkerton wrote in message ... . But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? Has it indeed? Do you have any *evidence* for this extraordinary claim? Please see comments in my post to this thread dated October 12 relative to my experiences with the Audible Illusions 3A. What you posted was a sighted preference, hardly evidence. If you can show that the Audible Illusions 3A has *measureably* better performance, then you have something to start from. Even then, the better performance could be due to better choice of resistor values, or a host of other possibilities like better matching, better switching, etc., rather than using expensive resistors vs not-so-expensive resistors I may be wrong but I *think* Stewart was questioning whether I had evidence that I found some line stages to sound better or different than other line stages, irrespective of the resistor issue. Because a few posts ago after you and Stewart both presented compelling empirical info about resistor measurements and performance I conceded on that issue. That is, based on information presented there is no basis to suggest that one resistor, no matter what the cost, will perform or sound any different than another resistor. That the Audible Illusions 3A sounded and performed "differently" in my system than other line stages sounded and performed in my system is a different matter altogether (I think). The question asked in the thread is "Do all preamps sound alike"? It has been my experience, that in my system. they don't all sound alike. You suggest that because my audition of the Audible Illusion 3A was sighted that my observations were not valid. (By the way, the performance of the 3A was "less" not "better" in my system than other line stages). I believe that if you read my comments closely that you will find that the fact it was sighted had no affect on my observation. I realize this is what they all say. But here it was graphically black and white. No blind test required. Literally hundreds of times I have listened to the Telarc Michael Murray performance of the Poulenc Organ Concerto. Heading into the final 3 minutes or so the recording (and at a live performance) I habitually brace myself for a faint but *very* deep organ passage which is sustained continuously for well over 90 seconds. Because it is sustained it is easier to gauge than a transient. Telarc says that this sustained note was at 23 HZ. It feels like a small earthquake (I live in the San Francisco Bay Area). But with the Audible Illusions that sustained note simply did not occur. It simply didn't happen. The faint groan of the organ didn't happen, the *seemingly* change in the barometric pressure (for lack of a better description) didn't happen, the very unique and easily identifiable flutter of the floor didn't happen. Turning up the volume to higher than normal did not make it happen. The bottom octave was clearly rolled off. I can't speak to *why* the lower octave was not reproduced. I offer some opinions in my original comments and both the dealer and the manufacturer confirmed that the unit was working to spec. Perhaps you can shed some additional light on that. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Robert C. Lang |
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#58
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Well Dude, perhaps amplify prior to the input of an amplifier, ie
preamplify? -Bill www.uptownaudio.com Roanoke VA (540) 343-1250 "Tat Chan" wrote in message ... Wylie Williams wrote: Georg Grosz wrote: If the two preamps were given a fair double blind test, and sounded different, one of them would probably be an incompetent design. I wish I had take more Philosophy classes that worked through logical thinking. Somehow when I make a post asking "Do preamps sound alike?" and there are a number of answers like this I imagine myself doing a comparison of two preamps, hearing a difference, then asking myself "Which one is the incompetent one. Let's check the specs. Hmmm, both have excellent specs. Could it be that both of them are incompetent in different ways?" Dude, what else is a pre-amp meant to do other than act as a source selector and volume control? As such, a pre-amp should be nothing more than a connection (maybe with some gain) to the power amp and as such have no distinct sound of its own. |
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#59
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#60
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Robert C. Lang wrote:
Chung wrote in message ... Robert C. Lang wrote: Stewart Pinkerton wrote in message ... . But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? Has it indeed? Do you have any *evidence* for this extraordinary claim? Please see comments in my post to this thread dated October 12 relative to my experiences with the Audible Illusions 3A. What you posted was a sighted preference, hardly evidence. If you can show that the Audible Illusions 3A has *measureably* better performance, then you have something to start from. Even then, the better performance could be due to better choice of resistor values, or a host of other possibilities like better matching, better switching, etc., rather than using expensive resistors vs not-so-expensive resistors I may be wrong but I *think* Stewart was questioning whether I had evidence that I found some line stages to sound better or different than other line stages, irrespective of the resistor issue. Because a few posts ago after you and Stewart both presented compelling empirical info about resistor measurements and performance I conceded on that issue. That is, based on information presented there is no basis to suggest that one resistor, no matter what the cost, will perform or sound any different than another resistor. Yes, and I think we were looking for evidence of said differences. What you said is that you strongly believe that there are differences, but that does not constitute evidence. Certainly others may not accept your belief as evidence that such differences exist. That the Audible Illusions 3A sounded and performed "differently" in my system than other line stages sounded and performed in my system is a different matter altogether (I think). The question asked in the thread is "Do all preamps sound alike"? It has been my experience, that in my system. they don't all sound alike. OK. You suggest that because my audition of the Audible Illusion 3A was sighted that my observations were not valid. Your observations in that case are not evidence. You certainly are right to choose your components based on your personal observations, though, so they may be perfectly valid for you. (By the way, the performance of the 3A was "less" not "better" in my system than other line stages). I believe that if you read my comments closely that you will find that the fact it was sighted had no affect on my observation. I realize this is what they all say. But here it was graphically black and white. No blind test required. Literally hundreds of times I have listened to the Telarc Michael Murray performance of the Poulenc Organ Concerto. Heading into the final 3 minutes or so the recording (and at a live performance) I habitually brace myself for a faint but *very* deep organ passage which is sustained continuously for well over 90 seconds. Because it is sustained it is easier to gauge than a transient. Telarc says that this sustained note was at 23 HZ. It feels like a small earthquake (I live in the San Francisco Bay Area). But with the Audible Illusions that sustained note simply did not occur. It simply didn't happen. The faint groan of the organ didn't happen, the *seemingly* change in the barometric pressure (for lack of a better description) didn't happen, the very unique and easily identifiable flutter of the floor didn't happen. Turning up the volume to higher than normal did not make it happen. The bottom octave was clearly rolled off. I can't speak to *why* the lower octave was not reproduced. I offer some opinions in my original comments and both the dealer and the manufacturer confirmed that the unit was working to spec. Perhaps you can shed some additional light on that. Definitely that difference, assuming it's real, is not caused by the type (or price) of the resistors. I would guess that perhaps that unit has a much lower input resistance, and that caused the output capacitance of the source to have a high-pass cut-off that is too high in frequency. Or that it has a coupling capacitor that is too small. Is there transformer coupling inside the unit? Do you have a schematic of the 3A? On the manufacturer's website, the specs for the M3A say that the error is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly does not agree with what you observed. Were you using the phono section? What you described can also be easily measured, if it was the high-level input that you were using. In fact, you can probably measure it yourself using a good voltmeter, if you have access to that unit. Play a test CD disc with constant-level low frequency tones, and see how the output level varies as you play different tones. It should be flat down to at least 20 Hz. Make sure that you connect the outputs of the preamp to the power amp while you make that measurement. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Sure, if the CD player, the preamp, or the power amp were poorly implemented, then they can easily get in the way. But competence in these components is easy to achieve today. That competence, unfortunatly, cannot be assumed, particularly in the high-end products. |
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#61
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#62
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(Nousaine) wrote in message ...
(Robert C. Lang) wrote: Chung wrote in message ... Robert C. Lang wrote: Stewart Pinkerton wrote in message ... . But your conclusions raises more questions (for me) they answer. If there are no practical or measurable quality differences among resistors what makes some passive sound better than others (and that indeed has been my experience)? Has it indeed? Do you have any *evidence* for this extraordinary claim? Please see comments in my post to this thread dated October 12 relative to my experiences with the Audible Illusions 3A. What you posted was a sighted preference, hardly evidence. If you can show that the Audible Illusions 3A has *measureably* better performance, then you have something to start from. Even then, the better performance could be due to better choice of resistor values, or a host of other possibilities like better matching, better switching, etc., rather than using expensive resistors vs not-so-expensive resistors I may be wrong but I *think* Stewart was questioning whether I had evidence that I found some line stages to sound better or different than other line stages, irrespective of the resistor issue. Because a few posts ago after you and Stewart both presented compelling empirical info about resistor measurements and performance I conceded on that issue. That is, based on information presented there is no basis to suggest that one resistor, no matter what the cost, will perform or sound any different than another resistor. That the Audible Illusions 3A sounded and performed "differently" in my system than other line stages sounded and performed in my system is a different matter altogether (I think). The question asked in the thread is "Do all preamps sound alike"? It has been my experience, that in my system. they don't all sound alike. You suggest that because my audition of the Audible Illusion 3A was sighted that my observations were not valid. (By the way, the performance of the 3A was "less" not "better" in my system than other line stages). I believe that if you read my comments closely that you will find that the fact it was sighted had no affect on my observation. I realize this is what they all say. But here it was graphically black and white. No blind test required. Literally hundreds of times I have listened to the Telarc Michael Murray performance of the Poulenc Organ Concerto. Heading into the final 3 minutes or so the recording (and at a live performance) I habitually brace myself for a faint but *very* deep organ passage which is sustained continuously for well over 90 seconds. Because it is sustained it is easier to gauge than a transient. Telarc says that this sustained note was at 23 HZ. It feels like a small earthquake (I live in the San Francisco Bay Area). But with the Audible Illusions that sustained note simply did not occur. It simply didn't happen. The faint groan of the organ didn't happen, the *seemingly* change in the barometric pressure (for lack of a better description) didn't happen, the very unique and easily identifiable flutter of the floor didn't happen. Turning up the volume to higher than normal did not make it happen. The bottom octave was clearly rolled off. I can't speak to *why* the lower octave was not reproduced. I offer some opinions in my original comments and both the dealer and the manufacturer confirmed that the unit was working to spec. Perhaps you can shed some additional light on that. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Robert C. Lang If what you say is true than wouldn't you agree that these differences would be completely revealed with a frequency response measurement taken at the input terminals of the loudspeakers? Or even at the inputs to the power amplifier? As pronounced as the bass frequency roll off was I would think it would be readily measurable. If I suggested otherwise I certainly didn't mean to. As humans we can ONLY hear level differences (sound pressure) and arrival time differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage to alter either when they are in a bypass mode. I don't know. Keep in mind that my observation of the bass roll off did not involve transients that in music can be tricky, at best, to compare lest you use a level matched A/B switch of some sort. On the contrary the difference I observed were an organ bass note that was sustained, continuously for 90 seconds. With the Audible Illusions that 23 HZ note was completely missing for the entire 90 seconds. I can only logically conclude that the Audible Illusions, in my system, rolled off sharply below 30 HZ. What do you think acounts for such audible, tactile (floor vibrations that did not occur as with other line stages), and visual (lack of room vibrations as there are with other line stages) differences? Robert C. Lang |
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#63
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Chung wrote in message
I would guess that perhaps that unit has a much lower input resistance, and that caused the output capacitance of the source to have a high-pass cut-off that is too high in frequency. Or that it has a coupling capacitor that is too small. Is there transformer coupling inside the unit? Do you have a schematic of the 3A? On the manufacturer's website, the specs for the M3A say that the error is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly does not agree with what you observed. Were you using the phono section? No. My observation was based primarily on the Telarc Poulenc Organ Concerto CD. What you described can also be easily measured, if it was the high-level input that you were using. In fact, you can probably measure it yourself using a good voltmeter, if you have access to that unit. Play a test CD disc with constant-level low frequency tones, and see how the output level varies as you play different tones. It should be flat down to at least 20 Hz. Make sure that you connect the outputs of the preamp to the power amp while you make that measurement. At my invitation Audible Illusion had every opportunity to make measurements, while the pre amp was in my system as they are only 20 minutes away. They did not think it was necessary based on my observations. By the way, the representatives of Audible Illusions never doubted the validity of my observations (I have only used the word "observation", never "evidence". Because as clearly stated in my original comments (the ones made in February 2000 at http://www.audioreview.com/Preamplifiers/Audible Illusions/PRD_118448_1591crx.aspx#reviews) I had a strong bias in favor of Audible Illusion because it is a local company and I had been in direct contact with the company to arrange a purchase. Audible Illusions took my observations and comments quite seriously and were never cynical. They found my observations to be quite compelling (and said so) because they involved more that just hearing (they also involved sight [lamps not vibrating] and feel [vibration of floor]. Audible Illusions offered an explanation that I retrieved from the archives of this group I made several years back. To put the Audible Illusion representative's comments in perspective it should be noted that my system is bi-amped. "The day after I wrote my comments Art Ferris, of Audible Illusions, in a email to me expressed his belief that because I was "driving several amplifiers, electronic crossover etc." he believed that the "paralleled load impedance" of my amplifiers was well below the minimum load impedance of 20kohm. Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferriss also stated that "in most normal systems", where the pre amp is driving an amplifier with an input impedance above 20kohm, I would not experience a problem." I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Sure, if the CD player, the preamp, or the power amp were poorly implemented, then they can easily get in the way. But competence in these components is easy to achieve today. That competence, unfortunatly, cannot be assumed, particularly in the high-end products. Agreed. But also that even competently designed gear such as the Audible Illusion 3A is not always a fit in all systems. Robert C. Lang |
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Robert C. Lang wrote:
Chung wrote in message I would guess that perhaps that unit has a much lower input resistance, and that caused the output capacitance of the source to have a high-pass cut-off that is too high in frequency. Or that it has a coupling capacitor that is too small. Is there transformer coupling inside the unit? Do you have a schematic of the 3A? On the manufacturer's website, the specs for the M3A say that the error is +/- 1dB from 2 Hz to 100KHz for the high-level input. So that clearly does not agree with what you observed. Were you using the phono section? No. My observation was based primarily on the Telarc Poulenc Organ Concerto CD. In that case, there is a huge discrepancy between your observations and the spec sheet. What you described can also be easily measured, if it was the high-level input that you were using. In fact, you can probably measure it yourself using a good voltmeter, if you have access to that unit. Play a test CD disc with constant-level low frequency tones, and see how the output level varies as you play different tones. It should be flat down to at least 20 Hz. Make sure that you connect the outputs of the preamp to the power amp while you make that measurement. At my invitation Audible Illusion had every opportunity to make measurements, while the pre amp was in my system as they are only 20 minutes away. They did not think it was necessary based on my observations. By the way, the representatives of Audible Illusions never doubted the validity of my observations (I have only used the word "observation", never "evidence". Because as clearly stated in my original comments (the ones made in February 2000 at http://www.audioreview.com/Preamplifiers/Audible Illusions/PRD_118448_1591crx.aspx#reviews) I had a strong bias in favor of Audible Illusion because it is a local company and I had been in direct contact with the company to arrange a purchase. Audible Illusions took my observations and comments quite seriously and were never cynical. They found my observations to be quite compelling (and said so) because they involved more that just hearing (they also involved sight [lamps not vibrating] and feel [vibration of floor]. Audible Illusions offered an explanation that I retrieved from the archives of this group I made several years back. How could they have taken your comments seriously if they did not try to get to the cause of the problem? Or give you a replacement first? To put the Audible Illusion representative's comments in perspective it should be noted that my system is bi-amped. "The day after I wrote my comments Art Ferris, of Audible Illusions, in a email to me expressed his belief that because I was "driving several amplifiers, electronic crossover etc." he believed that the "paralleled load impedance" of my amplifiers was well below the minimum load impedance of 20kohm. I would think that your electronic crossover is in *series* with the power amp, so that the preamp only sees the crossover as a load. Does your crossover has an extremely low input impedance, like less than 10K? Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferris is clearly technically incompetent. You can ignore everything he said, based on that comment. Mr. Ferriss also stated that "in most normal systems", where the pre amp is driving an amplifier with an input impedance above 20kohm, I would not experience a problem." Assuming that the +/- 1dB spec at 2Hz is achieved at 50K loading as stated in the specs, it would take a load of 5K to move the -1dB point to 20 Hz, if the output coupling capacitor was causing the roll-off. (If some interstage cap or transformer was casuing the roll-off, then output loading should not make any difference.) And even that still does not account for your observations, which were more like -6dB or worse at 23 Hz. Seems like you had a defective M3A. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Sure, if the CD player, the preamp, or the power amp were poorly implemented, then they can easily get in the way. But competence in these components is easy to achieve today. That competence, unfortunatly, cannot be assumed, particularly in the high-end products. Agreed. But also that even competently designed gear such as the Audible Illusion 3A is not always a fit in all systems. Robert C. Lang |
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Stewart Pinkerton wrote in message ...
On 21 Oct 2004 23:41:06 GMT, (Robert C. Lang) wrote: Chung wrote in message ... Robert C. Lang wrote: Stewart Pinkerton wrote in message ... Literally hundreds of times I have listened to the Telarc Michael Murray performance of the Poulenc Organ Concerto. Heading into the final 3 minutes or so the recording (and at a live performance) I habitually brace myself for a faint but *very* deep organ passage which is sustained continuously for well over 90 seconds. Because it is sustained it is easier to gauge than a transient. Telarc says that this sustained note was at 23 HZ. It feels like a small earthquake (I live in the San Francisco Bay Area). But with the Audible Illusions that sustained note simply did not occur. It simply didn't happen. The faint groan of the organ didn't happen, the *seemingly* change in the barometric pressure (for lack of a better description) didn't happen, the very unique and easily identifiable flutter of the floor didn't happen. Turning up the volume to higher than normal did not make it happen. The bottom octave was clearly rolled off. That may of course be literally true. Have you measured the frequency response of this generally well-regarded preamp? But here it was graphically black and white. No blind test required. Yeah, right. That is indeed 'what they all say', usually right before they can't tell any difference under level-matched DBT conditions... I can't speak to *why* the lower octave was not reproduced. I offer some opinions in my original comments and both the dealer and the manufacturer confirmed that the unit was working to spec. Perhaps you can shed some additional light on that. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. So you say, but you offer no evidence that this perception had any basis in the physical world. You suggest that because my audition of the Audible Illusion 3A was sighted that my observations were not valid. (By the way, the performance of the 3A was "less" not "better" in my system than other line stages). I believe that if you read my comments closely that you will find that the fact it was sighted had no affect on my observation. I realize this is what they all say. Quite so, hence you will understand my dismissal of your opinion. First, it doesn't matter. Audible Illusions (including at least two engineers in the company) found my observations to be dispassionate and plausible not to require measurements or dbts to confirm the obvious. Audible Illusions (only 20 minutes away) had the opportunity to make measurements; they chose not to. They came to the same conclusions I did. That is, that there *was* an audible bass roll off of the 3A in *my* system (not necessarily applicable to your system). Second, with respect to your remarkable propensity to curtly dismiss others opinions and require corroborative proof for such, by English definition *opinion* "is a belief or conclusion held with confidence, but not substantiated by positive knowledge or proof". Opinions are by *definition* unsubstantiated! This definition should be familiar to you because I have offered to you on several occasions in the past. I have never asked you to substantiate with measurements or with any other form of "evidence" your *opinion* on XRCDs or CD players, speakers, or anything else. It would be not only disingenious, but also unfair to you and to the discussion. Indeed, at times your pronouncements are validated only by the fervor with which you offer them. For example, this past January 21 I mentioned to the group (not you in particular) that I was considering several universal players. You exhorted "Pioneer DV-868 - accept no substitute!" The exchange went like this: I'm attending CES specifically to narrow my choices for a universal player so I can listen to DVD-A as well as SACD and CD. Pioneer DV-868 - accept no substitute! :-) And then when I asked for even a low-level clarification on one of your endorsements you didn't respond. No problem there, but I would hope that you would refrain from holding others to standards that you yourself don't adhere to. Robert C. Lang -------------------------------------------------------------------------------- |
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Jim wrote in message ...
(Robert C. Lang) wrote in : Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferris is blowing smoke on this one. High capacitance interconnects might affect the high end, but certainly not low frequencies. -- JS Frankly, That was my thinking at the time. Robert C. Lang |
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Stewart Pinkerton wrote in message ...
On 23 Oct 2004 14:45:38 GMT, (Robert C. Lang) wrote: (Nousaine) wrote in message ... As humans we can ONLY hear level differences (sound pressure) and arrival time differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage to alter either when they are in a bypass mode. I don't know. Keep in mind that my observation of the bass roll off did not involve transients that in music can be tricky, at best, to compare lest you use a level matched A/B switch of some sort. On the contrary the difference I observed were an organ bass note that was sustained, continuously for 90 seconds. With the Audible Illusions that 23 HZ note was completely missing for the entire 90 seconds. I can only logically conclude that the Audible Illusions, in my system, rolled off sharply below 30 HZ. What do you think acounts for such audible, tactile (floor vibrations that did not occur as with other line stages), and visual (lack of room vibrations as there are with other line stages) differences? What you report is shall we say, vanishingly unlikely, unless there was something *seriously* wrong with your system. Bear in mind that the 3A is specified as flat to -1dB down to 2Hz, and you'll see that what you are reporting is essentially impossible. BTW, it's worth remembering that, while John Curl is a talented and professional designer, Art Ferris is a graphic artist turned 'high end' audio salesman, so not to be relied on for anything technical! :-) How about something being "wrong" with the Audible Illusions? Or how about nothing being wrong with the Audible Illusions but it just innocently rolled off below 30 hz? Because, roll off notwithstanding the 3A did sound good. And if something is "wrong" with my system you care to offer your opinion as to what are the possibilities? Particularly, since the problem (lack of below 30 hz bass) has not been audibly evident with other line stages. Also, you have been quiet vocal in dissing the accuracy of tube gear. What in you opinion, if any, might that have contributed to the 3A performance? And as for the competence of Mr. Ferris, I'm not about to touch that one, except he did collaborate with others at Audible Illusions including engineers. Indeed, I had discussions with Mr. Ferris, and two engineers. Although I agreed with their conclusion, I did not "buy" their explanation. Robert C. Lang |
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Stewart Pinkerton wrote in message ...
On 23 Oct 2004 14:48:28 GMT, (Robert C. Lang) wrote: To put the Audible Illusion representative's comments in perspective it should be noted that my system is bi-amped. "The day after I wrote my comments Art Ferris, of Audible Illusions, in a email to me expressed his belief that because I was "driving several amplifiers, electronic crossover etc." he believed that the "paralleled load impedance" of my amplifiers was well below the minimum load impedance of 20kohm. An active crossover will not in general present a lower load impedance than would a power amplifier. The power amps are of course *not* directly connected to the preamp in such a situation, hence there is no question of any 'paralleled load impedance'. From your comments, It sounds like Art Ferris is utterly incompetent. Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferriss also stated that "in most normal systems", where the pre amp is driving an amplifier with an input impedance above 20kohm, I would not experience a problem." This is utter rubbish. The only possible effects due to high capacitance interconnects would occur in the extreme treble. It is simply not possible for cable capacitance and/or low load impedance to make a difference to the bass. I can't respond to what else you have written above, but I agree it has always been my understanding that high capacitance interconnects would could possible only effect the extreme treble, especially with a passive line stage. I can only say to an absolute certainty that in *my* system (and that's all I am talking about) that the lower octave was lacking with the 3A whereas as with most others line stages it was not an issue. Up until that time I thought that speakers were the limiting factor and that all pre amps sounded a like (if not identical). I learned from that experience that other parts of the chain can also get in the way. Sure, if the CD player, the preamp, or the power amp were poorly implemented, then they can easily get in the way. But competence in these components is easy to achieve today. That competence, unfortunatly, cannot be assumed, particularly in the high-end products. Agreed. But also that even competently designed gear such as the Audible Illusion 3A is not always a fit in all systems. However, what you report is simply not technically possible. So that I may further understand what you are talking about, what *specifically* is not technically possible? Robert C. Lang |
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B&D wrote:
On 10/23/04 2:43 PM, in article , "Chung" wrote: Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferris is clearly technically incompetent. You can ignore everything he said, based on that comment. Wow - that is a rather sweeping statement, Chung. Before passing judgement on someone else (It certainly seems we are all very quick to come to the conclusions like the ones you did) might be good to dig a little deeper, eh? So would you trust anything Mr. Ferris said regarding this problem? Or do you need to dig deeper before you can dismiss his comment that high capacitance interconnects could cause bass roll-offs? |
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On 23 Oct 2004 22:15:10 GMT, B&D wrote:
On 10/23/04 2:43 PM, in article , "Chung" wrote: Mr. Ferris also expressed concern whether I was "running low capacitance interconnect recommended for use with the Audible Illusion 3A. He expressed that high capacitance interconnects could account for bass roll-off. Mr. Ferris is clearly technically incompetent. You can ignore everything he said, based on that comment. Wow - that is a rather sweeping statement, Chung. Before passing judgement on someone else (It certainly seems we are all very quick to come to the conclusions like the ones you did) might be good to dig a little deeper, eh? You need dig no deeper than that blatantly erroneous statement by Ferris. If you were to dig deeper, you'd find that Ferris trained as a graphic artist, then moved into *selling* high-end audio. Technical credentials - zero. Judging by his statements quoted in this thread, technical knowledge also zero.................... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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Have you checked for the obvious?
- Was the subsonic filter enabled? - Is the switch for this function defective? Normally, I'd expect the subsonic filter to be applicable to the phono stage only, but since specs for the 3A available on the web don't give much information, who knows how it's implemented. |
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"Stewart Pinkerton" wrote in message
... On 23 Oct 2004 14:45:38 GMT, (Robert C. Lang) wrote: (Nousaine) wrote in message ... As humans we can ONLY hear level differences (sound pressure) and arrival time differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage to alter either when they are in a bypass mode. I don't know. Keep in mind that my observation of the bass roll off did not involve transients that in music can be tricky, at best, to compare lest you use a level matched A/B switch of some sort. On the contrary the difference I observed were an organ bass note that was sustained, continuously for 90 seconds. With the Audible Illusions that 23 HZ note was completely missing for the entire 90 seconds. I can only logically conclude that the Audible Illusions, in my system, rolled off sharply below 30 HZ. What do you think acounts for such audible, tactile (floor vibrations that did not occur as with other line stages), and visual (lack of room vibrations as there are with other line stages) differences? What you report is shall we say, vanishingly unlikely, unless there was something *seriously* wrong with your system. Bear in mind that the 3A is specified as flat to -1dB down to 2Hz, and you'll see that what you are reporting is essentially impossible. BTW, it's worth remembering that, while John Curl is a talented and professional designer, Art Ferris is a graphic artist turned 'high end' audio salesman, so not to be relied on for anything technical! :-) I gather that this is a passive "preamp". If so, it should not have a low frequency limit--unless there is a coupling capacitor somewhere in the circuit. If this capacitor is at the input, I can see no way that it can screw up the low frequency response, since the load impedance is known by the manufacturer. However, if it's at the output, the load is unknown, and if you have several parallel loads, it could move the pole up to where 23 Hz is down quite a bit. IMHO this would be a bad design choice, but stranger things have happened. You might try disconnecting as many devices as you can, and then see if the bass improves. Of course if you have a voltmeter and a stable frequency source, you can answer the question at once. Norm Strong |
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On 24 Oct 2004 15:19:50 GMT, (Robert C. Lang)
wrote: Stewart Pinkerton wrote in message ... On 23 Oct 2004 14:48:28 GMT, (Robert C. Lang) wrote: Agreed. But also that even competently designed gear such as the Audible Illusion 3A is not always a fit in all systems. However, what you report is simply not technically possible. So that I may further understand what you are talking about, what *specifically* is not technically possible? That high-capacitance cables, or low load impedance, could affect the bass. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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On 24 Oct 2004 15:19:14 GMT, (Robert C. Lang)
wrote: Stewart Pinkerton wrote in message ... On 23 Oct 2004 14:45:38 GMT, (Robert C. Lang) wrote: (Nousaine) wrote in message ... As humans we can ONLY hear level differences (sound pressure) and arrival time differences between our 2 ears. I'm wondering exactly how pre-amplifiers manage to alter either when they are in a bypass mode. I don't know. Keep in mind that my observation of the bass roll off did not involve transients that in music can be tricky, at best, to compare lest you use a level matched A/B switch of some sort. On the contrary the difference I observed were an organ bass note that was sustained, continuously for 90 seconds. With the Audible Illusions that 23 HZ note was completely missing for the entire 90 seconds. I can only logically conclude that the Audible Illusions, in my system, rolled off sharply below 30 HZ. What do you think acounts for such audible, tactile (floor vibrations that did not occur as with other line stages), and visual (lack of room vibrations as there are with other line stages) differences? What you report is shall we say, vanishingly unlikely, unless there was something *seriously* wrong with your system. Bear in mind that the 3A is specified as flat to -1dB down to 2Hz, and you'll see that what you are reporting is essentially impossible. BTW, it's worth remembering that, while John Curl is a talented and professional designer, Art Ferris is a graphic artist turned 'high end' audio salesman, so not to be relied on for anything technical! :-) How about something being "wrong" with the Audible Illusions? Or how about nothing being wrong with the Audible Illusions but it just innocently rolled off below 30 hz? There's nothing 'innocent' about a component specified as flat to 2Hz, rolling off at 30Hz! Because, roll off notwithstanding the 3A did sound good. And if something is "wrong" with my system you care to offer your opinion as to what are the possibilities? Particularly, since the problem (lack of below 30 hz bass) has not been audibly evident with other line stages. Your imagination seems to be the most likely culprit. Also, you have been quiet vocal in dissing the accuracy of tube gear. What in you opinion, if any, might that have contributed to the 3A performance? It's hard to be quiet vocal, but I have in point of fact never had a problem with tubed preamps, aside from phono stages, where noise is an inevitable problem. Indeed, tubed preamps have excellent overload capacity, and are generally nicely linear. Unnecessarily expensive to be sure, when compared with SS, but not audibly problematical. And as for the competence of Mr. Ferris, I'm not about to touch that one, except he did collaborate with others at Audible Illusions including engineers. Indeed, I had discussions with Mr. Ferris, and two engineers. Although I agreed with their conclusion, I did not "buy" their explanation. You should not have agreed with their conclusion, as it is technically impossible. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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