There are ultra low distortion amplifiers with less than 1ppm around now.
These ultra low THD amps would make an excellent platform to exchange some, or one, of these alleged substandard resistors/capacitors and measure the effect on distortion due to the ferro-magnetic content in their manufacture.
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The people who make these unsupported and (frankly) ignorant claims try very hard to not think about tubes.
Can't be done. It's magical and mysterious distortion undetectable by science, but easily detectable by sensitive ears, but only when they are allowed to peek.
Gentlemen,
In analysing capacitors the recent few posts, particularly from Charles, is true. That is not disputed. But nowhere do I read about quantatative results. Yes, cap A might be 10X better than cap B - so we should all go for cap A if we want the best regardless .... (define 'best')
But (for the umpteenth time), what about the effct IN AUDIO ? We can all go make the couplings of our garden hoses from silver because that is undisputedly higher quality ....... The other matter not addressed above - I repeat: A coupling capacitor is a d.c. block. There is no resulstant a.c.across it over the audio band. If no charge/discharge takes place, it matters not about di-electric absorbtion or whatever; all these things are at a constant, in other words resting. The only relevant characteristic of a coupling cap here is that it should not leak (or blow up because an insufficient working woltage was used). It is only when capacitors start acting capacitively e.g. in filters, that one might become concerned with internal shenanigans (and even then there remains the question of whether audible at all - but that is anolther topic.) I don't know how to explain it any better ....
apart from frowning on the implication that most designers over decades were all ignorant of this sort of thing, only sitting up now on the wake-up call of anecdotal nature with no measurements as back-up evidence.
In analysing capacitors the recent few posts, particularly from Charles, is true. That is not disputed. But nowhere do I read about quantatative results. Yes, cap A might be 10X better than cap B - so we should all go for cap A if we want the best regardless .... (define 'best')
But (for the umpteenth time), what about the effct IN AUDIO ? We can all go make the couplings of our garden hoses from silver because that is undisputedly higher quality ....... The other matter not addressed above - I repeat: A coupling capacitor is a d.c. block. There is no resulstant a.c.across it over the audio band. If no charge/discharge takes place, it matters not about di-electric absorbtion or whatever; all these things are at a constant, in other words resting. The only relevant characteristic of a coupling cap here is that it should not leak (or blow up because an insufficient working woltage was used). It is only when capacitors start acting capacitively e.g. in filters, that one might become concerned with internal shenanigans (and even then there remains the question of whether audible at all - but that is anolther topic.) I don't know how to explain it any better ....
apart from frowning on the implication that most designers over decades were all ignorant of this sort of thing, only sitting up now on the wake-up call of anecdotal nature with no measurements as back-up evidence.
All human sensory systems, sight, taste, touch, smell, and yes, even hearing are all subject to inaccuracy and failure. A bare foot on a cold dry floor can feel wet. Artificial flavorings can fool our tongues into perceiving real food while we're actually ingesting a food substitute (well...sort of), Looking at a graphic consisting of a black background crisscrossed with horizontal and vertical white bands will inevitably lead the eyes to see gray spots at the intersections that do not exist. And finally, the things we "know" (or think we know) can fool our ears into hearing things that exist only between our ears, not external to them. The list is endless.
If anyone can show any evidence that ferrous materials adversely affect the sound (I know what I hear doesn't count), I'd like to see it, so far nobody has.
Mike
If anyone can show any evidence that ferrous materials adversely affect the sound (I know what I hear doesn't count), I'd like to see it, so far nobody has.
Mike
Marce,
To go rather OT, here it may surprise you that many of the audio greats never listened to their products until after the design was completed; particularly after the 70s, when knowledge and instruments were capable of modelling hearing to the extent that whatever was audible, could by then be quantified as such.
Leak, Walker, Williamson, Self and many others (Doug is a member here and can correct me). I am unfamiliar with the Eastern scene, but I have never read about the following conversation taking place, e.g: "There's a little brightness around 4 - 5kHz. Shall we - let me see - decrease R39 somewhat; what do you say, Jack? .... Oh! You think it is rather lacking there! .... (momentary frown) ... Then we must increase the value .....
OH! You reckon we should change the mains cord .... "
Not contradicting you, Marce, but I did about the same ... must have done most things right over decades, if I have never had disagreement over the acceptability of my own amps.
Of course, commercial viability would be entirely dependant on the client's hearing taste. And with the variation in that .... For whose taste must the poor designer design?
To go rather OT, here it may surprise you that many of the audio greats never listened to their products until after the design was completed; particularly after the 70s, when knowledge and instruments were capable of modelling hearing to the extent that whatever was audible, could by then be quantified as such.
Leak, Walker, Williamson, Self and many others (Doug is a member here and can correct me). I am unfamiliar with the Eastern scene, but I have never read about the following conversation taking place, e.g: "There's a little brightness around 4 - 5kHz. Shall we - let me see - decrease R39 somewhat; what do you say, Jack? .... Oh! You think it is rather lacking there! .... (momentary frown) ... Then we must increase the value .....
OH! You reckon we should change the mains cord ....
"Not contradicting you, Marce, but I did about the same ... must have done most things right over decades, if I have never had disagreement over the acceptability of my own amps.
Of course, commercial viability would be entirely dependant on the client's hearing taste. And with the variation in that .... For whose taste must the poor designer design?
Interestingly, there's at least two well-regarded designers here who have admitted that they don't actually listen to their designs, they just have "formulas" that work. I'm a bit of a chicken in that I do listen to mine, but the work on the test bench gets me there without iterating perhaps 99% of the time. It's easier when you're designing boxes of gain that are not intended to have a "sound" but are meant to merely make a small signal larger.
i do listen to my own builds, i listen for humming,
hissing and other noise and make sure that you have
to keep your ears an inch from the speakers to hear those....
i keep my comments to myself most of the time,
i let those auditioning to decide for themselves,
i am one who doesn't get sore if someone has negative
criticisms of my amp, i listen to them and find out how i can do better next time....
i do listen to my own builds, i listen for humming,
hissing and other noise and make sure that you have
to keep your ears an inch from the speakers to hear those....
Shows up in the test measurements, but anal-retentive me just likes to make sure.
The other important thing to listen for is the tendency toward sporadic oscillation or squegging, especially after a clipping event.
so far, i have kept my listening to "just enough" levels so as to avoid clipping...
i am using floor-standers that has 90db of sensitivity so that mere 12 watter
6LU8 pp amps are more than enough for me.....
i have somebody who do some sort of "wine tasting" on my amps,
he minces no words and is very honest in his assessments...
i have yet to set-up testing equipment to do some testing, i found that
having someone or a group of listeners helps....
i am using floor-standers that has 90db of sensitivity so that mere 12 watter
6LU8 pp amps are more than enough for me.....
i have somebody who do some sort of "wine tasting" on my amps,
he minces no words and is very honest in his assessments...
i have yet to set-up testing equipment to do some testing, i found that
having someone or a group of listeners helps....
Suppose I had the opportunity to eliminate a coupling capacitor by using a properly designed DC servo. The other choice being to use whatever capacitor of my choosing (such as my latest 10uF teflons). Which would I do? I would choose to eliminate the capacitor every time! Would I try to measure the distortion caused by ferromagnetic parts? I both know it *is* there, at some level, and also that it is extremely difficult to measure, likely beyond anything in my collection of measuring devices. But I don't have to measure it. I know that NO Capacitor will have less distortion than even the best capacitor. And I see many well regarded audio designers take this same approach. When possible, they eliminate capacitors. DC Servo power amplifiers have been around, and usually among the most highly regarded, since the mid 1970's.
That's an important point. Why would one replace a cap that is so linear and neutral that it adds nothing audibly and measureably for a servo, that DOES measurably add unwanted stuff?
Replace a cap with an opamp and expect the sound to become better? Heresy!
Jan
To be fair, one can also set up a servo that adds nothing audible or measurable compared with a coupling cap. Of course, that DOES require engineering rather than voodoo incantations and vague handwaves.
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