The above reference sums matters up in an exact way, and would be about all that is required in this debate. But the debate will resurface every time someone with insufficient knowledge of the subject comes to a quite honest conclusion, however one that does not take all known facts into account.
It is such a pity that the learning curve occasionally becomes static because pet 'convictions', aquired quite logically and honestly at the time they 'surfaced', will then stubbornly be adhered to. Ergo, the initial honest learner gets switched onto a dead-end side track, from which there is mostly no return.
Perhaps some psychologist can be found to explain this to us. Thanks for the link, Cbdb.
It is such a pity that the learning curve occasionally becomes static because pet 'convictions', aquired quite logically and honestly at the time they 'surfaced', will then stubbornly be adhered to. Ergo, the initial honest learner gets switched onto a dead-end side track, from which there is mostly no return.
Perhaps some psychologist can be found to explain this to us. Thanks for the link, Cbdb.
cbdb said:
The problem is, he can have a proof, but it may not be repeated in different conditions. Dr. Richard Bandler once told a story how he wanted to manufacture pills called Placebo for usage in psychotherapy, but could not get over FDA, while lots of pills that work less effective than placebo are approved by FDA. Suggestions can cause miracles, like balancing of immune system to completely eliminate cancer, and there are many cases had been reported. The problem is, the only procedure that can be used to approve such methods causes an opposite effect when used. "I.e. prove me that your procedure works, but in order to prove you must use my procedure that causes your procedure not working".
If Stuart weren't on your side of the debate, he would have sited you for argumentum ad verecundiam.
John
Sy,
Based on my own experiences and those of several colleagues, I find your JJ12AT7 claim to be extraordinary.
Did you or did you not use sighted listening to help arrive at your conclusion re the superiority of the JJ 12AT7 over all other variants. Please answer unambiguously and quit being so evasive.
What 'classic" collectors' item versions' of the 12AT7 did you test. What was the context (ie over what range of operating conditions did you test). How many samples were tested. What confidence level applied to your result.
Based on my own experiences and those of several colleagues, I find your JJ12AT7 claim to be extraordinary.
Did you or did you not use sighted listening to help arrive at your conclusion re the superiority of the JJ 12AT7 over all other variants. Please answer unambiguously and quit being so evasive.
What 'classic" collectors' item versions' of the 12AT7 did you test. What was the context (ie over what range of operating conditions did you test). How many samples were tested. What confidence level applied to your result.
cbdb said:
I see from his basic comments he has found the same issue, no one wants to participate in any test where they might be wrong. Just too much to lose.
I was completely unambiguous about it and have posted my procedure and results on several occasions. Linearity was measured with spectrum analysis (AudioTester and M-Audio 196, with an HP 3581A as a backup/verification), microphonics by listening and pencil taps. If that's extraordinary to you, I'd recommend a few courses at a technical school.
Sy,
Since condescension appears to be your forte, I'll leave you to it. So the JJ measures better than other 12AT7 variants, displays less microphony and does not necessarily sound superior (unless you contend that measurement and microphony mean everything and can be used in isolation to assess the sonic merit of a component).
As for your not answering the other questions I posed to you - it was quite what I expected. You have proven to be an extremely slippery beast and I can't be bothered pursuing this matter any further.
In conclusion, all I can say is practice as you preach, or your credibility goes out the window.
Why DBTs don’t reveal differences between cables.
It’s the context: In an unfamiliar (and possibly stressful) context the subject’s brain is so busy trying to get a handle on the way the system sounds (ie how it reproduces music differently to his/her own system) and interpret music they have not heard previously that it is totally incapable of detecting lesser order differences like cables. I have experienced this on many occasions at friend’s homes.
However, in the context of your own system, in your own home, the sound of which you are totally familiar, using music you have listened to 100’s of times, small differences become quite apparent. Some negative differences may only become apparent after some time (usually as an irritation which makes you less inclined to listen to music). I am very confident that a rigorous DBT conducted in the context of the subject’s own system) in their own home using familiar music would yield a positive result (assuming normal hearing).
As to preconditioning always determining an outcome: the number of times I have obtained a result opposite to that expected leads me to believe that this influence is overrated.
Manufacturers of boutique cables are well aware that people can hear differences between interconnects and speaker cables. Many of them are deliberately engineered to sound different; the key issue being that different does not mean better. This is where the advertising spin and appearance comes into play. It encourages subjects to interpret any perceived difference as an improvement.
I shall now don a flak jacket and retire from this thread as the self proclaimed objectivist cheer squad circles in for the kill.
It’s the context: In an unfamiliar (and possibly stressful) context the subject’s brain is so busy trying to get a handle on the way the system sounds (ie how it reproduces music differently to his/her own system) and interpret music they have not heard previously that it is totally incapable of detecting lesser order differences like cables. I have experienced this on many occasions at friend’s homes.
However, in the context of your own system, in your own home, the sound of which you are totally familiar, using music you have listened to 100’s of times, small differences become quite apparent. Some negative differences may only become apparent after some time (usually as an irritation which makes you less inclined to listen to music). I am very confident that a rigorous DBT conducted in the context of the subject’s own system) in their own home using familiar music would yield a positive result (assuming normal hearing).
As to preconditioning always determining an outcome: the number of times I have obtained a result opposite to that expected leads me to believe that this influence is overrated.
Manufacturers of boutique cables are well aware that people can hear differences between interconnects and speaker cables. Many of them are deliberately engineered to sound different; the key issue being that different does not mean better. This is where the advertising spin and appearance comes into play. It encourages subjects to interpret any perceived difference as an improvement.
I shall now don a flak jacket and retire from this thread as the self proclaimed objectivist cheer squad circles in for the kill.
It's obvious that the debate over $700 cables won't be solved here. The original question (remember that?) asked if a big (14/2) power cord would be advantageous on a tube receiver. It is my opinion (and only my opinion) that it would not be, since most tube type receivers were definitely not "resolving enough to be able to hear the difference between power cords".
If you believe that a $700 power cord makes your system sound better AND you financially secure enough to buy one, then by all means make yourself happy. I don't satisfy either criteria, so I use the power cable from an old computer. I don't believe that anyone with even a well stocked lab could measure the electrical effects imposed on a properly designed amplifier by two different but properly designed power cables.
Now the differences between two different brands of 12AT7's can be heard AND measured. I have some experience here. I have about 1000 12AT7 tubes in just about every flavor ever used by the US millitary. I also have some European types. There are dozens of different constructions of 12AT7 type tubes. SY suggested a while ago that I try the JJ 12AT7 since they were the best there is, so I bought a pair of them. They are built totally different than any other 12AT7 that I have seen. The plate looks like it came from a 6DJ8.
During the design phase of the Simple SE I was looking for a tube with worldwide availability that had enough gain to drive a triode wired KT88 to full power from a CD player. Several of the common tube types were eliminated but the venerable 12AT7 remained a viable choice.
It had been stated on this forum that 12AT7's sound terrible in a SE amp. It was stated that this is because they produce too much second harmonic. Was this true?
I ran several tests on several types of 12AT7's. It is true that some tubes do produce copious amounts of 2H under some conditions. The signal level and bias current where the 2H peaks is different for each type of 12AT7 and even for different tubes of the same make and date code. These tests were all conducted with a resistive load at various bias currents and supply voltages. 3H and higher harmonics are even more varied, but substantially lower. In most cases operating the 12AT7 at currents of 5 mA or more results in the lowest THD. The JJ tubes did behave somewhat differently than most of the others, and the absolute worst case level of 2H was lower than most other types. They are the most well behaved types at low currents (2 mA) but only 2 tubes were tested.
The results were somewhat different with a CCS load. The CCS lowers the 2H output on ALL 12AT7's tested. The reduction was dramatic. This is expected, and is a common result with most triodes. An ideal triode produces no harmonics with an ideal CCS load. The 3H and higher harmonics are also reduced, but not by a great amount. Here the JJ "advantage" is not as great. Since the JJ already had a lower amount of 2H. I have all of the data on paper, and it will be on my web site when I finally find the time to finish redoing it.
What about the sound. In some amplifiers it is easy to see how all of the different 12AT7's including the JJ would sound different. In the Simple SE the differences are not as dramatic because of the CCS load. The JJ does sound a bit different than the others. Does it sound better? I don't know. The difference is not great enough for me to buy JJ's when I have zillions of "free" ones to choose from. I have heard from a few Simple SE builders who have rolled 12AT7's and among those with a preference, the JJ is the most often mentioned.
Does my testing or SY's testing present sufficient evidence to suggest that the JJ 12AT7 would sound best in all amps with all music in all situations? I don't think so.
Now lets bring up another "truth" that gets brought up occasionally by some members of this forum including SY. Do all 12AU7's suck? Does the "suckiness" change with the type or variant of 12AU7? Does a CCS load make them suck less? I don't have the answer to this one yet, and it will be a new thread when I do. I have thousands of these in a bunch of different constructions. They can't all suck, can they?
If you believe that a $700 power cord makes your system sound better AND you financially secure enough to buy one, then by all means make yourself happy. I don't satisfy either criteria, so I use the power cable from an old computer. I don't believe that anyone with even a well stocked lab could measure the electrical effects imposed on a properly designed amplifier by two different but properly designed power cables.
Now the differences between two different brands of 12AT7's can be heard AND measured. I have some experience here. I have about 1000 12AT7 tubes in just about every flavor ever used by the US millitary. I also have some European types. There are dozens of different constructions of 12AT7 type tubes. SY suggested a while ago that I try the JJ 12AT7 since they were the best there is, so I bought a pair of them. They are built totally different than any other 12AT7 that I have seen. The plate looks like it came from a 6DJ8.
During the design phase of the Simple SE I was looking for a tube with worldwide availability that had enough gain to drive a triode wired KT88 to full power from a CD player. Several of the common tube types were eliminated but the venerable 12AT7 remained a viable choice.
It had been stated on this forum that 12AT7's sound terrible in a SE amp. It was stated that this is because they produce too much second harmonic. Was this true?
I ran several tests on several types of 12AT7's. It is true that some tubes do produce copious amounts of 2H under some conditions. The signal level and bias current where the 2H peaks is different for each type of 12AT7 and even for different tubes of the same make and date code. These tests were all conducted with a resistive load at various bias currents and supply voltages. 3H and higher harmonics are even more varied, but substantially lower. In most cases operating the 12AT7 at currents of 5 mA or more results in the lowest THD. The JJ tubes did behave somewhat differently than most of the others, and the absolute worst case level of 2H was lower than most other types. They are the most well behaved types at low currents (2 mA) but only 2 tubes were tested.
The results were somewhat different with a CCS load. The CCS lowers the 2H output on ALL 12AT7's tested. The reduction was dramatic. This is expected, and is a common result with most triodes. An ideal triode produces no harmonics with an ideal CCS load. The 3H and higher harmonics are also reduced, but not by a great amount. Here the JJ "advantage" is not as great. Since the JJ already had a lower amount of 2H. I have all of the data on paper, and it will be on my web site when I finally find the time to finish redoing it.
What about the sound. In some amplifiers it is easy to see how all of the different 12AT7's including the JJ would sound different. In the Simple SE the differences are not as dramatic because of the CCS load. The JJ does sound a bit different than the others. Does it sound better? I don't know. The difference is not great enough for me to buy JJ's when I have zillions of "free" ones to choose from. I have heard from a few Simple SE builders who have rolled 12AT7's and among those with a preference, the JJ is the most often mentioned.
Does my testing or SY's testing present sufficient evidence to suggest that the JJ 12AT7 would sound best in all amps with all music in all situations? I don't think so.
Now lets bring up another "truth" that gets brought up occasionally by some members of this forum including SY. Do all 12AU7's suck? Does the "suckiness" change with the type or variant of 12AU7? Does a CCS load make them suck less? I don't have the answer to this one yet, and it will be a new thread when I do. I have thousands of these in a bunch of different constructions. They can't all suck, can they?
Believe me, if I make a claim of sonic superiority of capacitor A versus capacitor B or power cord A versus power cord B, in the absence of well-defined measurements demonstrating a difference above accepted audible thresholds, it will either be supported by controlled listening tests or I will be very clear that the differences I think I'm hearing may well be imaginary. Hmmm, that's exactly what I've done in the past... what a clever, slippery person I am!
As a philosophical note, a tube cannot have a sound. A circuit using the tube can. A tube is a dumb device, a single component. As an amplifying device, its linearity is easily quantified. True, someone might want the tube to be nonlinear to allow the circuit to act as an effects box. I've also been pretty clear that my stated preferences are not in that direction, and that if someone wants a tube circuit to make the sound "prettier" or "mellower" or what-have-you, my advice will not get them there.
A more linear amplification device is "better" in my universe, where emotion or timing/pace/rhythm in music is the responsibility of the musicians, not the power cord.
As a philosophical note, a tube cannot have a sound. A circuit using the tube can. A tube is a dumb device, a single component. As an amplifying device, its linearity is easily quantified. True, someone might want the tube to be nonlinear to allow the circuit to act as an effects box. I've also been pretty clear that my stated preferences are not in that direction, and that if someone wants a tube circuit to make the sound "prettier" or "mellower" or what-have-you, my advice will not get them there.
A more linear amplification device is "better" in my universe, where emotion or timing/pace/rhythm in music is the responsibility of the musicians, not the power cord.
mach1 said:
Sure! After the 5'th session of listening to the same tune it is apparent that it makes me feel sick of it. 😎
If the range of tubes you tested and sample size were sufficient to warrant your unqualified conclusion I’ll EAT a JJ 12AT7.
You haven't noticed a debate going on here? Your learned Professor Lesurf offers plenty of comment and a decent argument, but no proof. So what you've done is appealed to a higher authority, and that makes yours a fallacious argument.
What are your physics credentials?
John
mach1 said:
Your conclusion on "Why DBTs don’t reveal differences between cables", it's based on your personal confidence?
By the way, who are these people that are denying the testers the freedom to do DBT in the context of the subject’s own system in their own home using familiar music?
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