| serengetiplains |
| Anyone know the dielectric constant of kraft paper? I seem to recall it's pretty low .... in the neighbourhood of 2, but I don't know why I think that and the source of that thought might in any event be quite unreliable. |
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| serengetiplains |
| Ouch, that's high. Thanks Chris. |
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| Tweeker |
| This one attributes a value between 1.5 and 3. Craft paper is a kind of nebulous item, its not something whos dielectric value is set in platinum-iridium. The oil you use is also important. |
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| serengetiplains |
| Thanks, Tweeker. |
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| Tweeker |
Hmm, the clippercontrols link I listed also listed this:
Gerber Oatmeal (In Box ) 1.5 |
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| anatech |
Hi Tweeker,
Yes, you are correct. But if you search the first article, it's listed at a value of 4. They also mention the oil type and the fact that it will change the dielectric constant if you change the oil.
That's why I posted the link to the article.
-Chris |
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| TwoSpoons |
| Which suggests that '4' is really the dielectric constant of the oil, and the kraft paper is just there to hold the oil in place. |
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| anatech |
Partially. I don't know what the DC is for dry kraft paper. You would have to measure it in a nitrogen (or similar gas) atmosphere so the paper really is dry.
-Chris |
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| Tweeker |
| The clippercontrols link actually lists its paper as "dry",though it does not specify type. |
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| Tweeker |
| This link is very interesting, giving constants on a few woods, and values at one MHz and 3 GHz on some items. Gives Paper (bond) as 3.0. |
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| anatech |
Hi Tweeker,
Cool. That answers that. Of course you wouldn't use it dry. It would take on water. Don't want that. Therefore you need to impregnate it with something first.
-Chris |
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| anatech |
Hi Tweeker,
There is an interesting entry in there. The "Loss Tangent" for silicon is 0.005 @ 1 GHz, a vacuum is 0 I guess. One reason for a difference in sound between SS and tubes? For comparison, a polystyrene cap has a loss of 0.00033 @ 3 GHz. Hmmmm.
-Chris (see, I read the linked page) |
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| Curmudgeon |
| Nice links above. Very interesting, thank you. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
Anyone know the dielectric constant of kraft paper? I seem to recall it's pretty low .... in the neighbourhood of 2, but I don't know why I think that and the source of that thought might in any event be quite unreliable. |
Mind if I ask why you're asking?
se |
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| serengetiplains |
| Hi Steve, I want to better understand its utility in a capacitor. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
Hi Steve, I want to better understand its utility in a capacitor. |
Ah, ok. By the way, some of the separator papers used for capacitors are made of hemp rather than wood fiber.
Also, Steve Bench did some linearity tests on a variety of caps including a number of film caps and the PIO performed as good or better than the film caps.
If you're not already familiar with it:
The "Sound" of Capacitors
se |
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| serengetiplains |
My goal is to make a capacitor with a dielectric constant <1.9.
For low voltage use, perhaps a dielectric like a loose-weave silk or cotton would work well? Anyone think why not? |
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| Tweeker |
| JP4 has a dielectric constant of 1.7, though it likely to evaporate on you. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
My goal is to make a capacitor with a dielectric constant <1.9. |
So you're basically just chasing after numbers?
| quote: | | For low voltage use, perhaps a dielectric like a loose-weave silk or cotton would work well? Anyone think why not? |
Size for one thing. Unless you're only wanting to make picofarad caps. Second, neither cotton nor silk have dielectric constants as low as you want to go.
The claims made for cotton's dielectric constant of 1.4 are misleading as it only applies to cotton in its raw form, i.e. cotton balls, due to the vast amount of air that makes up the total volume. In textile form, dielectric constant is higher, and higher than the sub-1.9 figure you're chasing after.
se |
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| poobah |
Tweeker,
That is a cool list!
Serangetti,
Rice bran came in at 1.6 to 2.0. The Asians use rice to make paper... maybe???
Bet someone in Japan is already selling them for $200 a pop. |
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| serengetiplains |
| Foam polypropylene? |
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| serengetiplains |
| Anyone know someone at Porex who can get me a sample of porous teflon or polypropylene film? |
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| serengetiplains |
| quote: | Originally posted by Steve Eddy
So you're basically just chasing after numbers?
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Yup. Numbers is it. |
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| poobah |
Do you plan to impregnate with oil???
I only ask because the voltage breakdown will likely change when the material is foamed.
I have been looking into teflon films and all the makers warn of pinholes. |
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| serengetiplains |
I can understand that pinholes would become a concern at higher voltages, but for coupling purposes in low voltage situations, perhaps the bigger the pinhole the better?
I'm currently having a capacitor manufacturer experiment with a paper-in-Fluorinert (1.86 dielectric k) construction. No word yet on whether it might succeed. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
Yup. Numbers is it. |
Well, this is a society that largely worships the quantitative over the qualitative so I guess I can't blame you.
Enjoy the chase.
se |
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| serengetiplains |
| The hunch I'm chasing follows the observation that evil dielectric absorption largely correlates with dielectric constant such that the lower the DC the lower the DA the higher the signal transfer fidelity. |
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| MQracing |
[QUOTE]Originally posted by serengetiplains
[B]My goal is to make a capacitor with a dielectric constant <1.9.]
amorphous FEP teflon by dupont is said to be either 1.92 or 1.93... I forget which.
"regular" FEP teflon is close to 2.0 or 2.2... forget exactly... you can look these materials up on dupont's website.
Mike |
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| serengetiplains |
Thanks, Mike. Fluorinert comes in at 1.75-1.91, depending on the variety, but it's liquid, so requires a suspending solid to hold it in place. The particular variety of Fluorinert I'm testing is FC-84, which has a DC of 1.86. Porous teflon is 1.5 and higher, depending on the pore size, and porous polypropylene should be about the same. One possibility is to wind a capacitor with two layers of dielectric, one layer of foam ptfe/pp, the other solid ptfe/pp, the solid layer to prevent arcing or electrostatic whatever (I have no idea).
If teflon capacitors at 2.1 DC sound better than polypropylene at 2.2, can you imagine what a 1.8-1.5 DC capacitor would sound like? |
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| Tweeker |
Any foamed cap is going to be huge. Foamed dielectrics tend to be used where you want the lowest possible capactiance...
I suppose it might be possible to build a paper in butane cap into a little pressure vessel. Butane k=1.4, its alot more common than fluorinert. |
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| serengetiplains |
| Yes, capacitor size correlates with DC. Tis a problem that cannot be cured. But for certain applications where inductance is not an issue, and where larger size can be accommodated, lower DC is the only way to better sound. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
The hunch I'm chasing follows the observation that evil dielectric absorption largely correlates with dielectric constant such that the lower the DC the lower the DA the higher the signal transfer fidelity. |
What exactly makes dielectric absorption so evil? What exactly is its effect on signal transfer fidelity? I can see how it would be a problem with something like a sample and hold circiut, but for an analogue signal?
se |
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| jcx |
http://www.designers-guide.org/Modeling/da.pdf
also
http://www.national.com/rap/Applica...1570,28,00.html
point out that dielectric adsorption has a very successful linear model that doesn’t affect audio signals (sub ppm linear freq response variations vs the "pure C" model in most continuous filter applications)
no good theory linking da with distortion - do you have the ability to measure even polystyrene distortions?
a big issue is water, water is polar, has huge dielectric constant and everything absorbs water, papers/fabrics of organic fibers adsorb multiple percent - water even diffuses through oil impregnants - you'll need to vacuum bake to dry and then hermetically seal any of your experiments to avoid absorbed water dominating the dielectric effects as you try to go lower
even with < 0.1% equilibrium water absorption polystyrene has measurable dielectric changes - I recall seeing a report of 10X increase of 1KHz dielectric loss for polystyrene with absorbed water |
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| Steve Eddy |
Right. DA has been made into a huge Bogey Man, and it is in certain applications such as sample and hold circuits. But I haven't seen anyone demonstrate that it affects analogue audio signals in any appreciable way.
I'm beginning to think it's the case of the Bogey Man that wasn't there.
se |
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| poobah |
JCX,
The National article by Bob Pease does in fact say the soakage (DA) can be a detriment to AC coupled amplifiers.
Steve Bench also has some convincing tests on his website... with REAL data. Paper in oil showed the best results... hmmmmm.
I agree that much more "non-ear" testing needs to be done; but this looks real. |
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| Tweeker |
| quote: | Based on polarization/dielectric constant considerations for minimization of dielectric absorption, the best films for audio applications are teflon and polypropylene. Runners up would be polyethylene and polystyrene, based on these considerations alone. Throughout this discussion, I have assumed that dielectric absorption and the dielectric constant are directly correlated.
Apparently, when polarizability factors predominate, the time constant for relaxation of the field induced dipole is critical. Otherwise, one would expect polypropylene to have a lower dielectric absorption than polystyrene, which is not the observed result. This can be reasoned by re-examining what is being polarized by the field in each. In the case of the polystyrene, the pi-electrons in the aromatic rings (which have been modeled, in the past, as a "free electron gas") can orient electronically, with less mechanical change in the polymer structure. Hence, it can relax faster. In contrast, the polarization of polypropylene involves more mechanical change of the structure, and hence a slower relaxation rate. |
From Anatech's first link in thread. Discussing PS vs PP in particular. |
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| Steve Eddy |
| quote: | Originally posted by poobah
Steve Bench also has some convincing tests on his website... with REAL data. Paper in oil showed the best results... hmmmmm. |
Which is interesting given that paper in oil caps are far far worse than film caps when it comes to DA.
se |
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| Tweeker |
| quote: | | Yes, capacitor size correlates with DC. Tis a problem that cannot be cured. |
Its a bit worse when it comes to a foamed dielectric or air cap, youl have a lower breakdown strength to contend with vs a solid. |
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| Joules |
| Yes, you can make your own capacitors it's not hard they are to simple. I use to make cap for high voltage use -15kv- using aluminum foil and glass plate worked quite well. As time went by I figured out better ways of making them. One thing I found out by just experimenting is that the alum foil plates needed to be very solidly stuck to the glass plates. assembled "dry" they would his and buzz like you would not believe vibrating to tune of the signal, so I smoothed the aluminum foil on to the plates with oil. Wow what a difference much quieter and much better performance in the circuit. It's as if energy was lost vibrating the alum plate back and forth. So for audio use, wrap / compress them tite. |
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| jcx |
| quote: | Originally posted by poobah
JCX,
The National article by Bob Pease does in fact say the soakage (DA) can be a detriment to AC coupled amplifiers.
Steve Bench also has some convincing tests on his website... with REAL data. Paper in oil showed the best results... hmmmmm.
I agree that much more "non-ear" testing needs to be done; but this looks real. |
you mean this? - I don't see audio frequency mentioned
"Other applications in which soakage can degrade performance are those involving fast-settling ac active filters or ac-coupled amplifiers. In Fig 6's circuit, C1 can be a Mylar or tantalum unit because it always has 0V dc on it, but making C2 polypropylene instead of Mylar noticeably improves settling. For example, settling to within -0.2 mV for a 10V step improves from 10 to 1.6 sec with the elimination of Mylar's dielectric absorption."
Mylar may not be the best but you'll have to work at it to find an example of reasonable audio utility where frequency response is affected by da to within orders of magnitude of the 0.1 dB threshold detectable in dbt
Bench's "data" is pretty weak, and I assumed that we were in general talking about dielectrics better than mylar (which leaves out the popular silver-mica acording to Bob's data) - the obviously bad curves from Bench' are electrolytics and Hi-K ceramic |
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| poobah |
"ac-coupled amplifiers"... right in the text! Interstage coupling caps are blocking DC/coupling AC between amplifiers.
I have no vote regarding the effect at audio frequencies though. When capacitors require seconds, or fractions thereof, to discharge; it is entirely plausible that audio distortion results. |
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| poobah |
I would like to see Bench's set up for measurements... schematic with part numbers. A little strange in that what he labels as "hysterysis" is probably the effects of DA.
You're right though... WEAK data, not compiled in such a way that someone else could duplicate his results (methinks a lot of people do that on purpose).
Commendable in the regard that unlike most speaker cable people; he at least publishes something... other than an opinion. |
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| serengetiplains |
| Poobah, I think it's almost beyond discussion that DA, or something to which DA tightly correlates, is audible. For some who post on these websites, nothing is known with enough certainty to say anything meaningful about anything, let alone to allow one to make progress. Personally, I'm fine with guessing down probablistic lines, using information I'm able to glean to inform that guessing. For instance, when an engineer of a military capacitor manufacturer tells me that signal integrity is higher the lower the DA, I take that as a sign that DA, or something to which DA tightly correlates, affects signal integrity. Cyril Bateman has performed a series of stringent tests on capacitors, testing for distortion in different capacitors using different designs and dielectrics. His observations follow observations of those who use only their ears as a guide: capacitors with a lower DC (= lower DA) sound better, hence the heirarchy: electrolytic, mylar, polypropylene, polystyrene, teflon. Also of interest, he found that film/foil varieties measure better than metallized counterparts. One reason I would posit for this result---as another guess, for you unknowing types---is that film/foil types have a layer of air between the dielectric and the metal surface, and we all can reasonably guess the effect this would have on resulting DA etc. |
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| serengetiplains |
| quote: | Originally posted by jcx
no good theory linking da with distortion |
Do you mean, no good theory in the entire universe, or no good theory of which you are aware? Cyril Bateman, ee + ex-capacitor designer, says re DA:
| quote: | | The main characteristic I have found, which clearly relates to dielectric absorption, is the magnitude of the second harmonic [he means, "the magntitude of measurable second harmonic distortion a capacitor produces on an AC signal"]. |
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| SY |
| So you would predict, then, that if I checked the harmonic distortion spectrum of a normal audio signal passed through an RC coupling circuit, I would see a noticeable difference between a crummy bipolar electrolytic and, say, a nice Teflon cap that some kind soul sent me? |
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| SY |
| quote: | | One reason I would posit for this result---as another guess, for you unknowing types---is that film/foil types have a layer of air between the dielectric and the metal surface, and we all can reasonably guess the effect this would have on resulting DA etc. |
We can also reasonably guess the effects of any air gap on microphonics and modulation of capacitance with vibration... |
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| anatech |
Hi SY,
That's easy, stick them in a high gain circuit and give them a "twack" with your finger nail. You might get different notes, and so have a new instrument! ;)
-Chris |
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| serengetiplains |
| quote: | Originally posted by SY
So you would predict, then, that if I checked the harmonic distortion spectrum of a normal audio signal passed through an RC coupling circuit, I would see a noticeable difference between a crummy bipolar electrolytic and, say, a nice Teflon cap that some kind soul sent me? |
I would be inclined to guess down those lines, certainly.
| quote: | Originally posted by SY
We can also reasonably guess the effects of any air gap on microphonics and modulation of capacitance with vibration... |
No doubt. What we most need is to finger the factor that accounts for lower THD of film/foil types. Could be lower DA. Could also be the non-linear R of metallized dielectrics. I'd be inclined to guess that all these factors, including greater vibration etc, combine into one global effect. |
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| serengetiplains |
For those interested, here are quotations from Bateman's multi-part capacitor series titled "Capacitor Sound," beginning July 2002 in Electronics World and subsequent issues. Bateman is an electrical engineer, now an editor, I believe, of EW, and formerly was a capacitor design engineer, no slouch when it comes to capacitors. To test capacitor distortions, he designed a rig using a computer soundcard with FFT software using pricey audio-grade (cough) components like Holco resistors (should have used Vishays). Initial measurements obtained using this rig were discarded because he realised, part way through his project, that capacitors he used as critical coupling capacitors in the rig---metallised PETs---introduced distortions that ruined the result (an observation that, itself, could provide the basis for interesting discussions about "measuring"). So he ditched the PETs for MKPs (should have used teflons) etc etc, and here's what he found. I give a random selection of quotations, but before doing so I give his most fundamental finding, which is that .... drum roll .... dielectric absorption is the primary factor producing *easily measurable* capacitor distortion. Say it isn't so. Alas, the golden ears have known this for years without resort to or the need for measurements, but how nice now to have measured results now saying so, especially from a once-capacitor design engineer who had to reverse his long held view ("scientific," no doubt, especially when imposed on others) that capacitors are not much different one from another and that DA has little to do with AC-coupling signal integrity etc. Here are some quotes from Bateman which read almost as from a golden ears' book of experience:
"Many capacitors that distort little when sine wave tested without a DC bias voltage, exhibit much bigger distortions with increasing polarisations [ie, bias voltage]."
"Polar dielectrics [ie, mylar] are lossier and take longer for the dielectric to return to its original uncharged state. Polar dielectrics produce easily measured 'dielectric absorption' effects, especially apparent in thin [read: low voltage] dielectrics."
Polystyrene is "perhaps the best of the easily obtained plastic film dielectrics ... It has an N150 temperature coefficient, a very small tan d and the smallest [next to teflon] dielectric coefficient of all film materials."
"For the best, undistorted sound, dielectric choice is obviously all-important."
"A poor dielectric principally influences the levels of the second and even harmonics produced by the capacitor."
"An internal non-ohmic connection in the capacitor ... introduces significant levels of odd harmonics [watch those connections!], the third having the biggest amplitude."
"I have measured many metallised film capacitors having very large third harmonic levels, frequently as much as +20dB higher than others in the same batch. I have not found this problem when foil electrodes are used with the same dielectric."
"To avoid any possibility of a non-ohmic end connection we could use a solderable, soft metal foil electrode and solder it directly to the lead out wires. This is exactly the time proven assembly used by a large maker of extended foil/Polystyrene capacitors. It produces a near perfect, non-distorting capacitor."
"Self-inductance of [an extended foil rolled] capacitor body is then less than its equivalent length of lead wire. These capacitors have almost no self-inductance apart from the 7nH per cm of the lead wires used to connect them to the circuit."
"The resistance of the metallised electrode combined with aluminum's temperature coefficient of 0.0039 results in a non-linear resistance. This may at least partially explain some of the larger third harmonic distortions [in metallised vs. foil capacitors]."
In measurements of metallised stacked vs. rolled PET capacitors, "the stacked film capacitors usually exhibited an increased third harmonic compared to the wound type."
"Depending on circuit arrangements, many capacitors could produce audible distortions. Perhaps this should not surprise us. Audiophiles have claimed to be able to 'hear' PET capacitors for many years."
I believe that for 0.1uF to 1uF values, metallised PET capacitors should first be distortion tested. Because of their rapid increase in second harmonic with DC bias, they should not be used with significant DC bias, relative to their rated voltage, in high quality audio equipment."
"To ensure the claimed performance of a published audio circuit can be repeated, the designer should declare the make, model and rated voltages of the capacitors. Simply stating ceramic, film etc. is totally unacceptable. These tests illustrate how a capacitor with an acceptable single frequency distortion test can produce significant intermodulation on audio when presented with multiple frequencies."
"Single tone 1kHz amplifier harmonic distortion tests ignore distortions caused by the rising impedance of capacitors at low frequencies. It is now clear that large amplitude bass notes and drum beats in music can result in peculiar intermodulation distortions, in an otherwise apparently good amplifier. For my part, I shall disregard any published audio designs which do not report low frequency intermodulation distortion claimsor low frequency harmonic distortion results, especially if the capacitors used are not properly chosen and [!] adequately defined."
All electrloytic capacitors are ****. (paraphrase)
Bi-polar electrolytics are better than all other electrolytics but are still **** and are easily bested by metallised PET, which are themselves ****. (paraphrase)
"Dielectric behaviour with voltage [ie, DA] depends on the voltage gradient in volts/micron and the characteristics of the dielectric. Its [ie, DA] effects are more readily apparent at low voltages with thin dielectric. The dielectric used in low voltage electrolytics is exceptionally thin. Consequently we find increased effects from dielectric absorption when meauring these types [ditto with thin vs. thicker film film capacitors]."
Electrolytic capacitor distortion increased exponentially the higher the RMS test voltage, including at test [signal] voltages less than 1V. (paraphrase)
_______________________
Bateman gives THD and IM distortion numbers for various capacitors under various test conditions. Those numbers define a range of -150dB to -50dB for the various harmonics concerned. Here are some examples:
Class 2 (ie, noisy) ceramic, zero DC bias = 0.00074% THD, -133dB 2HD, -102dB 3HD.
Class 2 ceramic, 18VDC bias = 0.00205% THD, -95dB 2HD, -99dB 3HD.
Another Class 2 ceramic, 18VDC bias = 0.145% THD, -63dB 2HD, -58dB 3HD.
Class 1 ceramic (C0G), zero DC bias = 0.00006% THD, -128.5dB 2HD, -129dB 3HD.
Class 1 ceramic, 18VDC bias = 0.00009% THD, -122dB 2HD, -129dB 3HD.
Foil polystyrene, 18VDC bias = 0.00005% THD, -129dB 2HD, -131dB 3HD. No visible IM distortion.
Foil polypropylene, 18VDC bias = 0.00005% THD, -128dB 2HD, -131dB 3HD. No visible IM distortion.
Wima FKP2 foil polypropylene, 18VDC bias = 0.00006% THD, -126dB 2HD, -131dB 3HD. No visible IM distortion.
Metallised PET, 18VDC bias = 0.00225% THD, -92dB 2HD, -110dB 3HD. IM distortion clearly visible.
63V polar electrolytic, 30VDC bias = 0.00461%THD, -86dB 2HD, -104dB 3HD. IM distortion clearly visible.
63V bipolar electrolytic, 30VDC bias = 0.00225%THD, -93dB 2HD, -122dB 3HD. IM distortion not visible. |
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| serengetiplains |
| None of the above, of course, is in any way audible. |
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| SY |
| quote: | Originally posted by anatech
Hi SY,
That's easy, stick them in a high gain circuit and give them a "twack" with your finger nail. You might get different notes, and so have a new instrument! ;)
-Chris |
I have. The results deeply increased my cynicism regarding "designer" capacitors. The best-performing caps in that test were mass-market Sprague, Panasonic, and WIMA. The worst was a hideously expensive Teflon cap.
BTW, this is the basic flaw in the idea of reducing dielectric constant via a foam or mesh dielectric. |
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| anatech |
Hi SY,
So have I. Slapping mic cable on the floor is another fun trick. You get the oddest "bwang" noises out the speakers.
This all comes from my desire to mess with the average audiophiles head. :devilr:
-Chris |
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| poobah |
I have been wanting to read Bateman's stuff. Is there acces to it anywhere without spending $200 for the back issues?
I do question whether harmonic distortion alone is a valid test.
Were I to guess, and I should know better than to do it here, (;) ) I would have to think that some other effect, rather than the sub 100 db levels of THD are causing what is heard.
It is easy enough to make a rough model of DA. Has anyone ever run simulations?
Just for fun... how 'bout cryo caps using frozen JP4? :D |
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| serengetiplains |
Poobah, send me a pm.
I wouldn't be surprised if Bateman's THD figures constitute a proxy for more complex and subtle---and more irritatingly audible---forms of distortion. |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
I wouldn't be surprised if Bateman's THD figures constitute a proxy for more complex and subtle---and more irritatingly audible---forms of distortion. |
Isn't this just more cart-before-the horse thinking? Instead of just making assumptions (unless that's all one is interested in), wouldn't it make more sense to first establish actual audibility and then use that as a means to pin down the cause?
Otherwise, all you have are a bunch of speculations which may or may not be the case.
se |
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| poobah |
Establishing audibility raises all the ugliest of issues... controlled testing.
Speculation is just that, but it is also the vehicle of discovery is it not?
Suppose for the moment we are barking up the wrong tree by looking for THD... then let's look for a new measurment.
I am the biggest skeptic of all, but for the comments/writings I have heard from guys I truly respect; I think this "capacitor thing" might be real. |
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| serengetiplains |
| quote: | Originally posted by Steve Eddy
Isn't this just more cart-before-the horse thinking? Instead of just making assumptions (unless that's all one is interested in), wouldn't it make more sense to first establish actual audibility and then use that as a means to pin down the cause? |
Whoa, hold the horses! To establish "actual audibility," you first gotta hear something, then correlate measurements to hearing, which is to say hearing comes first---it's a priori, as some might say. Assumptions are tricky things, hey Steve? |
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| Tweeker |
Out of curiousity Id like to see some strontium titanate (k=233), silver mica, teflon, and vacuum capacitors tested.
Id also like to read this paper.
Hollow microcrystalline keratin fibers (k = 1.7) in butane (k=1.4) capacitors? |
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| serengetiplains |
| quote: | Originally posted by Tweeker
Hollow microcrystalline keratin fibers (k = 1.7) in butane (k=1.4) capacitors? |
I *assume* it would sound good. |
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| serengetiplains |
| quote: | Originally posted by poobah
Suppose for the moment we are barking up the wrong tree by looking for THD... then let's look for a new measurment.
I am the biggest skeptic of all, but for the comments/writings I have heard from guys I truly respect; I think this "capacitor thing" might be real. |
I completely agree that if THD is the wrong measurement, which it probably is---or, better, is one probably one of a handful of relevant measures, not all of which are presently known---we must look elsewhere, which would mean to forge new ground, which gets you back to speculating in the series hear-speculate-determine&test. So I'm not jumped on as a moron, allow me to state my assumption that that series does not state a lockstep linear series of investigation, but folds back onto itself such that hearing determines speculation determines testing determines speculation etc. |
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| Steve Eddy |
| quote: | Originally posted by poobah
Establishing audibility raises all the ugliest of issues... controlled testing. |
Yes. Because until you control for known phenomena with regard to subjective perception, those elements will always remain as an ambiguity and you've not got anywhere.
| quote: | | Speculation is just that, but it is also the vehicle of discovery is it not? |
But speculation is not an end in itself. Unless all you're interested in is showing off for the girls or something.
| quote: | | Suppose for the moment we are barking up the wrong tree by looking for THD... then let's look for a new measurment. |
Ok. But if the reality is that none of this is actually audible in the first place, what's the poing?
| quote: | | I am the biggest skeptic of all, but for the comments/writings I have heard from guys I truly respect; I think this "capacitor thing" might be real. |
And it just might be real. I have never claimed that it is not. My point is that you're not truly going to know that until you first establish actual audibility. Otherwise, ambiguity will remain and you're really no farther down the road than when you started.
se |
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| Steve Eddy |
| quote: | Originally posted by serengetiplains
Whoa, hold the horses! To establish "actual audibility," you first gotta hear something... |
I would say you first have to perceive something.
| quote: | | ...then correlate measurements to hearing... |
I would say then you determine whether the perception was due to something actually heard or something merely perceived. In other words, establish actual audibility.
Then you start correlating measurements, and then you may ultmately end up discovering causation. Don't forget, correlation and causation are not one and the same.
| quote: | | which is to say hearing comes first---it's a priori, as some might say. |
I define hearing as perception as a result of actual audibility as opposed to perception that may be due to other, non-related causes.
se |
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| poobah |
| I am ALWAYS interested in showing off for girls. |
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| SY |
| Advice: make sure the room isn't too cold. Trust me on that one. |
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| poobah |
I sure would like to hoist a glass with some of you brainiacs... some of my best hangovers have been in California & Canada
Sy... you're very right... also watch what you do with fiberglass curtains... :whazzat: |
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| SY |
| quote: | | I sure would like to hoist a glass with some of you brainiacs |
Liquor cabinet is always open at our place. Steve Eddy, OTOH, is a strict Muslim and cannot drink. But he does have fifteen wives. |
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| poobah |
| Is that why he's grouchy? |
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| anatech |
Hi Tweeker,| quote: | | Multi-Chip-Module circuit printing results suggest that the low-cost composite made with HF (from avian sources) and plant oil (from soybean) has the potential to replace the dielectrics in microchips |
Does this mean we could catch avian flu from IC's and caps? :xeye:
I believe there is an effect there, audibility is a sticky ball I wouldn't want to touch!
-Chris |
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| anatech |
Hi poobah,
Yah, 15 wifes would make anyone grouchy! :whazzat: |
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| poobah |
NO... NO... NO! :smash:
It will be all of two days before someone is selling bird fiber caps for $2000 apiece. The $4000 units will be made from California Condors and Bald Eagles; of course for reasons of sonic superiority. Panda's will be next... :hot: |
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| anatech |
| How much for Polar bear?:bigeyes: |
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| poobah |
| you see my poin then... |
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| Tweeker |
| Polar caps wont do except in SS, you want brown for SE amps, grizzly for PP. Chicago are good for decoupling. |
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| poobah |
You guys are nutz... nutz I say!
Polar caps............................. |
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| anatech |
| Polar caps, they sound cool.:cold: But they are a bear to install! |
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| Steve Eddy |
| quote: | Originally posted by anatech
Polar caps, they sound cool.:cold: But they are a bear to install! |
I'm in a pretty good mood right now so I'm going to forgive you for that. :)
By the way, I love your avatar.
se |
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| DSP_Geek |
| Just from a sense of curiosity, has anyone tried comparing the sound of one large capacitor versus a number of smaller units in parallel? All other things being equal, I'd expect ESL and ESR effects to be smaller. |
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| anatech |
Thanks Steve!:grouphug:
DSP_Geek, a bunch of smaller ones are usually less expensive. They probably do sound better.
-Chris |
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| poobah |
What's this Anatech? Do moderaters get their own special set of of smiley's and stuff... something above and beyond the prosthetic forehead?
BTW... Congrats, Your Majesty |
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| Tweeker |
| I have special :wiz: :drink: powers. |
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| poobah |
| I still want your resume... |
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| Tweeker |
| quote: | | Just from a sense of curiosity, has anyone tried comparing the sound of one large capacitor versus a number of smaller units in parallel? All other things being equal, I'd expect ESL and ESR effects to be smaller. |
I have little direct experience with this, but have heard there is some phase distortion with this in cossovers. Its great in PSUs.
Sadly, its the vacuum in my resume thats lacking. |
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| poobah |
We won't discuss resume vacuums; only minds.
Don't be a bad child... nothing to win. Beotch.... |
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| anatech |
Hi poobah,
No special smiley's. There are all there, but it's hard to find what you're looking for sometimes. But another member showed me how to do this ... |
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| anatech |
However, I did it wrong. The image has to be posted on a site to link to.
-Chris |
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| Tweeker |
| Under the selection of 24 smilies is a javascript window labeled "Get More", this is where most of the other smilies come from. People who use it get more.:lickface: |
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| poobah |
| I'm just an engineer with a bad case of ADD... can't type either |
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| DSP_Geek |
| quote: | Originally posted by anatech
DSP_Geek, a bunch of smaller ones are usually less expensive. They probably do sound better.
-Chris |
I don't know about less expensive. PartsExpress pricing on 5 x 10 uF Solens is 5 x $4.32 = $21.60, whereas a 51 uF part is $13.92.
I do suspect the paralleled parts might sound better, for the same reason that two small power supply caps could have better performance than one large one. Note that switching supplies tend to have paralleled capacitors in the filtering circuits.
Francois. |
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| SY |
| The problem with multiple parallel is that you've got to get connections to them. As you add more and more caps, the connections get longer and longer. |
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| anatech |
Hi Francois,
My error, I was thinking of electrolytics. With films that may not hold true due to the improved construction. You are at two extremes, there may be a better price point with only two - or not.
In switching power supplies we are talking about electrolytics. The smaller ones in parallel do yeld lower esr, etc. Different situation.
-Chris |
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| poobah |
Good point SY,
In large inverters (50 kW) with banks of caps, we have to go to extremes to be sure that each cap "sees" the same length of wire and its associated inductance... else one cap carries the lions share of the transients.
:xmastree: |
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