Capacitor's re-visited

[rrcrain]

The old electrolytic caps have a tendency to De-form with time if left idle, or used at a fraction of their rated voltage.

Now, this discussion about "fully" forming the new poly caps to their full rated voltage, often 400 VDC, has me wondering. Will these caps "de-form" back to the voltage level for the circuit they are in over time?

[Carlspeak]

If you are referring to Sean's post #23, I think his is another example of a single extemporaneous recollection of a personal experience. Thus, I am a bit skeptical.

While I feel there may be some value to cap 'forming', I also strongly believe the results are minimal and only noticeable on very high end speakers like his father's. I suspect doing a similar process with new caps going into classic speakers with their vintage drivers will not pay off.

It's all about the music

Carl

Carl's Custom Loudspeakers

[Guest Bret]

>I think his is another example of a single extemporaneous recollection of a personal experience. Thus, I am a bit skeptical.<

Carl, the question is; how many uniform extemporaneous recollections of a personal experience by different observers does it take to rise to the level of "evidence?"

A resistor is a pretty darn simple device.

An inductor is a pretty darn simple device.

A capacitor has a bunch of "moving parts" and they aren't made the same way with the same materials. I hear that some capacitors can even be microphonic, like a vacuum tube. . .

What I really wish the skeptics would all do is run an experiment or two before they skepticulate. I'm not advocating a particular capacitor or a combination or a type.

As you dismiss these things via "masking" and other failures of the brain (Julian Hirsch's garage evidently stunk as a listening room, he had to have accustomed himself to that (masking) in order to hear anything in there), you might consider that were you to have someone stalking you and carrying a weapon, and you reported it to the professionals (police) you could be easily dismissed as needing anti-psychotic medications; you might be dismissed as someone suffering from paranoia. You might be dismissed as someone who watches too much TV, has a vivid imagination, is "attention-seeking," or has reasonably reached an incorrect conclusion and is actually under Federal investigation explaining the weapon and the constant appearance of the same investigator. We might even discover there is a "need" in the human psyche to invent such conspiracies as we are pattern-seeking creatures and need to make sense of randomness.

Or it could be you were randomly picked for extinction by a lunatic.

Just because there may be an alternate explanation does not mean that the first explanation is wrong.

I dare say people have been sent to the gas chamber with fewer witnesses reporting less-similar recollections of personal observations.

You don't have to believe that, either. I can't prove it is true.

Bret

[rrcrain]

I'm a bit of the same opinion myself given I'd fully expect the capacitors to "deform" over time to the actual applied working voltage.

[Carlspeak]

>

>........"What I really wish the skeptics would all do is run an

>experiment or two before they skepticulate. I'm not

>advocating a particular capacitor or a combination or a type......."

Nor am I. However, most, if not all, of these classic speakers need to have their original, dated paper/oil and/or NPE caps replaced due to leakage, drifting in propeties and escalating ESR. The debate that has ensued here and in the AR discussion area is which brand/type of new cap to use and separately, whether or not the new ones need to be 'broken in'.

If you haven't already perused the 35 'capacitor myths' posts (over 2500 views) in the AR discussion area, please do. FYI, your wish for an experiment above has been answered there. Please read the "skepticulater's" experiment summarized in the following link:

http://www.members.aol.com/pjay99site/captest2.htm.

I think it does a pretty good job addressing the type of cap question.

Over 2500 views indicates a very high level of interest by those visiting CSP. That's by far the most popular disucssion subject in recent memory. I believe many who visit are restorers looking for advice/ideas on what caps to use. Most are probably refoaming and recapping as part of their restoration project - hence the high level of interest. Refoaming typically restores the woofers to their original operating condition (hopefully). Not much excitment there other than resotring the bass register. On the other hand, the recapping step affects a far greater proportion of the audible frequency spectrum and has more options for the restorer to consider:

1) should I recap with a similar cap to maintain the original performance characteristics (e.g., replace a NPE with a NPE recommended by some who post here)?

2) should I recap with a more modern type of cap like a metallized film or film/foil cap? Must these be 'formed' or 'broken in'?

3) should I bust the budget and opt for a 'boutique' cap I think (read hope) will give me a significant improvement in listening pleasure because it costs a lot more? [personally, I don't think vintage speakers will benefit signifantly from these caps]

IMHO, short of spending oodles of cash on boutique caps, I strongly recommend DIY restorers replace those old caps and experiment with questions 1) & 2) above a bit. It won't cost a great deal of money.

The mere fact that all who have posted on this subject and argued their various positions is self-evident that the differences are relatively subtle and highly subjective.

As I've written before, "SONIC BEAUTY IS IN THE EAR OF THE BEHOLDER"

I wish I could enlarge and bold the font here....

FIND OUT FOR YOURSELF WHICH IS BEST FOR YOU!!!

It's all about the music

Carl

Carl's Custom Loudspeakers

[rrcrain]

One more opinion.

A local business I frequent took on the task of re-capping the crossover in an old set of Snell speakers. Since they've never sold Snell and didn't have any experience with them, they contacted the manufacturer, looking for advise and direction on how to proceed. According to what they told me, Snell expressed the opinion that they would have used polyproplyene caps at the time, if they had been available. They believed it was best to replace the old, worn out elelctrolytics with the newer poly caps.

Different speakers, different ears and different caps...

[Carlspeak]

>One more opinion.

>

>A local business I frequent took on the task of re-capping the

>crossover in an old set of Snell speakers. Since they've never

>sold Snell and didn't have any experience with them, they

>contacted the manufacturer, looking for advise and direction

>on how to proceed. According to what they told me, Snell

>expressed the opinion that they would have used polyproplyene

>caps at the time, if they had been available. They believed it

>was best to replace the old, worn out elelctrolytics with the

>newer poly caps.

>

>Different speakers, different ears and different caps...

>

>

Interesting comment because I have recapped a pair of Snell Model A's (visit my website for some pics) with poly caps. It was quite a project indeed. Peter S. used oodles of 4 uF caps in various size 'bundles' to get a particular value. After prying up the glued bundle from the XO board, I discovered a single, flat, disk-shaped pF valued ceramic bypass cap at the bottom which, I suspect, also did double duty as a gluing surface.

Also totally agree with your last sentence above - and the beat goes on.......

Carl

Carl's Custom Loudspeakers

[Guest Bret]

"Myth, myth!"

"Yeth?"

Carl, there's no need for us to even debate.

But technically we can say that a thing is right or wrong.

Someone went to great lengths to back-up their position that all capacitors sound exactly the same (to put us "dumb fools" in our place). They then make suggestions as to how to compensate for the differences by adding small value resistors.

Evidently we can prove that capacitors sound exactly alike in carefully controlled listening tests. By adding a resistor to some capacitors we can make them sound even more exactly like the others than they did before we added resistance.

Others, to-which we didn't add resistors, which already sounded exactly alike, were unidentifiable in listening tests, but presumably are more inaudibly different than they are when made absolutely, completely, inaudibly different after we add resistance.

Of course, all the controlled listening tests proved that there is no audible difference to make less audible.

But, evidently we'll find even less than zero difference if we add small value resistors.

**********************************************************

This is a new concept and I think I'm going to patent it as a device: The new D-FER; or "Dumb Fool Effect Resistor." Using them we can D-FER the whole subject:

If you want to make two identical capacitors even more identical than identical, just put a D-FER in series with them.

This we will call a Dumb Fool Effect Transistor in Series, or D-FERinSe, for short.

It is a perfectly ineffectual device, so will not change the sound of any identical capacitor to which it is attached.

What I'm saying is that if you put one on your capacitor you cannot hear the D-FERinSe.

If you do not put these on the speakers there is no D-FERinSe to hear.

But the REAL beauty is that with them soldered in place there is a D-FERinSe you cannot hear in a controlled listening test.

Bret

[dynaco_dan]

Hi Bret;

Thank you for a great hifi funny.

[Carlspeak]

If you're considering recapping your speakers, I suggest you visit the AR discussion threads and check out the "capacitor myths" posts and the "capacitor myths revisited" posts and download the report available in the latter thread.

Some good info. there to help you make a decision.

It's all about the music

Carl

Carl's Custom Loudspeakers

[jwjensen356]

Carl, I am in the midst of recapping a pair of Dynaco A-50 (twin woofer + one tweeter) systems. I opted for the ClarityCaps (partially on the basis of the HumbleHomemadeHiFi.com survey). I've only done the replacement of the caps in one of the speaker boxes so far. Sounds fine but I so far have found no difference in audio quality to what it was before.

The big woofer cross-over cap (24µF) was clearly marked as an electrolytic. the smaller tweeter (5µF) cap simply said NP. Using a DVM I checked for leakage resistance of both original capacitors. When touched to the leads, the DVM immediatly shows the charging effect and within a second or so measures a high value of resistance. Considering they are 30+ years old I was quite impressed that they seem 'like new'.

But being electrolytics, I am glad I am replacing them.

John

[Carlspeak]

>Carl, I am in the midst of recapping a pair of Dynaco A-50

>(twin woofer + one tweeter) systems. I opted for the

>ClarityCaps (partially on the basis of the

>HumbleHomemadeHiFi.com survey). I've only done the

>replacement of the caps in one of the speaker boxes so far.

>Sounds fine but I so far have found no difference in audio

>quality to what it was before.

>

>The big woofer cross-over cap (24µF) was clearly marked as an

>electrolytic. the smaller tweeter (5µF) cap simply said NP.

>Using a DVM I checked for leakage resistance of both original

>capacitors. When touched to the leads, the DVM immediatly

>shows the charging effect and within a second or so measures a

>high value of resistance. Considering they are 30+ years old

>I was quite impressed that they seem 'like new'.

>

>But being electrolytics, I am glad I am replacing them.

>

>John

It's become my opinion that electrolytic caps may well be inexpensive, but they inherently have a limited life; something akin to foam surrounds. On the other hand,caps will probably outlast you and I. Clarity caps look like a good value PP cap, similar to Solens.

Enjoy the music. Because........

It's all about the music

Carl

Carl's Custom Loudspeakers

[dynaco_dan]

Hi John;

It is a well known fact that you can only A - B quickly, two at a time, whether it is a cartridge, amp, pre-amp or speaker.

Our memory of more than two items is too difficult to compare.

You can A - B a pair of caps, with a switch, but it is too long a span of time to remove and re-install a cap and try to compare them accurately.

Excepting if the cap was obviously defective.

If, as I have suggested in a much earlier write-up, connect a simple 2-way speaker, a single capacitor only, up to a multi-position switch setup and run the two cap wires out from the cabinet to this test box.

There can only be one cap in the speaker crossover for a valid test.

Any number, types and models of caps can be audibly compared, only two at a time though.

[Carlspeak]

Yet another 'one man show' review of some caps priced more towards the high end.

FYI and reading pleasure

http://www.audiocircle.com/circles/index.php?topic=54218.0

[soundminded]

I've listened to the capacitor debate for a long time and frankly I've always been skeptical of any audible differences. PeteB's report that to audiophiles' surprise, in a fair AB test they couldn't hear a difference beteen different types didn't surprise me, it's what I expected. This caused me to do some thinking. I realized that the reason all capacitors sound the same is that in reality they are the same. Here's why. A capacitor is made by placing an insulator between two conductors. The conductors of most capacitors are foil, usually aluminium but they could be copper (more expensive) but it hardly matters. The insulators whether paper, or mylar are made up of the same atoms, carbon, oxygen, hydrogen, perhaps some nitrogen and in some types some halogens. That also doesn't matter. When a voltage appears across the conductive plates, the electrons migrate within the atoms towards the positively charged plate but they cannot escape the strong electropositive pull of their nucleii. This slight migration is called displacement current. It doesn't matter whether or not the atoms are bound up in cellulose molecules or polypropylene molecules, the phenomenon is the same. The main difference is that residual acid in the paper making process will slowly chemically degrade the cellulose causing it to become thinner and therefore over time, the capacitance will increase. The breakdown voltage for paper of a given thickness may be lower than that of polypropylene but it doesn't matter either if you don't exceed the rating. Minor differences in parasitic electrical values such as ESR of different capacitor types shouldn't matter at audible frequencies in loudspeaker crossover networks. The comment about putting a series resistor measured in tenths of an ohm in a circuit to compensate for these minor differences probaby won't have any audible effect. These differences may be related to the way the leads are attached to the foil, not the capacitor insulating material. The variation they introduce is probably smaller than the variation due to manufacturing tolerences from one capacitor to another. Therefore the only advantage I can see for polypropylene is long term stability. Personally, I use the electrolytics myself.

[Carlspeak]

Sorry Soundminded, but here's another capacitor comparison study. This one appears much more rigorous than the prior, 'one-man-show' cap study.

FWIW, the mega-bucks Dueland caps used in one of my other posts (KLH 5 recap) rated the highest for loudspeaker crossovers.

http://www.tempoelectric.com/caps.htm

I am slowly coming to the conclusion from what I've read in countless posts on caps both here and on other audio sites, that the debate boils down (in many cases) to the subjectivists (non-techie listeners) vs the objectivists (techie engineer, theory & data driven types). Is this coincidence or, is there something to this apparent phenomenon? Don't know....

[soundminded]

Sorry Carl but it's all fluff. In fact from a technical standpoint it is so poor it really wasn't worthy of a good electronics hobbyist magazine let alone any professional journal. There was not a single measurement. The evaluations were based strictly on opinions. There was no explanation or correlation between perceived opinions of "betterness" and differences in electrical parameters. In fact we don't even know if two capacitors which have the same numbers on the outside are even close in their actual capacitance. This is the kind of audiophile claptrap that sells products. Is the better sounding amplifier the better amplifier? Better sounding to whom? Often the better amplifier doesn't disguise the flaws of other equipment with its own complimentary flaws. The solid state amplifier with power bandwidth to 20 khz and flat response makes the shrill speakers sound shrill, doesn't produce the muddy upper bass in an underdamped speaker which has no real bass the way a low damping factor rolled off high end tube amplifier will. Cartridges with high end peaks were deliberately selected for console phonographs which had no high end. Did that make them better cartridges? See the last column on the top and bottom? That's where you click "purchase."

[Carlspeak]

Sorry Carl but it's all fluff. In fact from a technical standpoint it is so poor it really wasn't worthy of a good electronics hobbyist magazine let alone any professional journal. There was not a single measurement. The evaluations were based strictly on opinions. There was no explanation or correlation between perceived opinions of "betterness" and differences in electrical parameters. In fact we don't even know if two capacitors which have the same numbers on the outside are even close in their actual capacitance......."

Like I wrote above: "the debate boils down (in many cases) to the subjectivists (non-techie listeners) vs the objectivists (techie engineer, theory & data driven types). Is this coincidence or, is there something to this apparent phenomenon? Don't know.... "

[soundminded]

Actually what it boils down to is what is the goal of a high fidelity sound system. For some like me, it is to reproduce the sound of live unamplified music. That was the original and in my view only legitimate goal of high fidelity is about. Therefore the only meaningful listening comparisons are between the results of the efforts of recording engineers and designers of high fidelity equipment and live music. That is what Acoustic Research and some of the small handful of companies of an earlier era spoken about here are about. That is what makes those companies, their efforts, their products, and this site more valuable than others. The efforts to achieve that goal can only have success in a systematic investigation of how real musical sound is produced and how to narrow the differences between that and what the machines produce. This requires scientific training and study if for no other reason than to see if a new effort gets you closer to the goal or further away. All other efforts are basically shooting in the dark. When that goal is removed and substituted by what people "like" on the spur of the moment, or their particular personal preferences, that opens up a market for an entire universe of endlessly diverse products, each different from the other and and different from live music. It also opens up an endless opportunity for profits because once an objective goal is achieved with sufficient adequacy, the only questions become ones of convenience, reliability, and cost.

Why does this effort matter? Because live music at its best is a beautiful sound but unfortunately a sound machines rarely if ever reproduce sufficiently well to bring equal pleasure to those who listen to live music critically. How do we know that this is true? Because people still spend hundreds of millions of dollars to build concert halls and opera houses in the hope that they will create the acoustic enhancement that makes music sound its best and because people still pay good money and inconvenience themselves to go to live concerts when it is far cheaper and easier to buy audio equipment and listen at home to recordings. But people who listen only to recordings or amplified commercial music don't know what they are missing.

The fact is that for the time being, this problem has beaten the best minds who attempted to it. The industry is no closer today to solving it than it was 30 years ago. Instead, it has relied on an endless stream of mostly useless me-too products whose cost spirals up endlessly, only matched by the advertising claimed for it. That it is a failure mode was demonstrated to me just again in the last few months with the disappearance of Harvey Electronics in Bridgewater NJ in a high end strip mall. Its expensive products sold in an affluent and relatively sophisticated market generating insufficient profit long enough to keep the doors open. Will there ever be a revival of this industry? Will it ever be renewed? On the face of it, you wouldn't think so. But I'm reading a book by a famous British neurologist who is a doctor at Columbia Presbyterian Hospital who claims there is a direct and unique link between the way the human brain and nervous system is organized and music. In fact he claims no civilization of any era in any place has been found without some form of music. Fossilized musical instruments have been found in caves, instruments which are 50,000 years old. He also cites a large number of anecdotal stories about the medical effect of music on the brain and human body. This unbreakable link may be our best hope that interest in real music and efforts to create convincing facsimiles of it may one day be revived.

[Carlspeak]

Thanks Soundminded for your thoughtful insights.

If I may, I'd like to sum up the last five sentences in your prior post in one sentence... It can be found below just above my name.

[Carlspeak]

Oh no, more capacitor shootout links!!!

http://www.ecp.cc/cap-notes.html

http://www.10audio.com/sonicap_oimp_multicap.htm

http://www.altavistaaudio.com/caps.html

http://www.vhaudio.com/21capacitorshootout.pdf

[soundminded]

Sorry Carl but once again no cigar. These are four utterly incompetent writeups. There wasn't even an attempt made in any of them to measure how close the actual capacitance values came to what was printed on the package. The first one was so crude, the author connected some of them with leads attached to alligator clips. This brings up a point. While we often model various electrical devices mathematically in very simple terms, in the real world, they have many parasitic components which can affect performance depending on the circuit. For example how the leads were configured can affect series inductance and shunt capacitance. A real mathematical model is far more complicated than a simple capacitor. They didn't even make an effort to measure DC leakage. BTW, both the more detailed mathematical model and real world measurements of that model in a lab are junior level courses for EE students in college. It's their first year of specilization after more general engineering and science courses. The measurements are what every electrical engineer would demand and even serious electronics hobbyists and tinkerers have a right to expect. Again, these are marketing articles, not engineering reports. They should carry no credibility. They only give some opinions by some people used in one or a few circuits. Like wires, resistors, switches, and all other purely electrical devices, they have a purely electrical function which can be defined, whose criteria for design can be established, and against which their performace can be measured. This in not properly called an "objectivist" point of view, it is a rational point of view. Once again, whether a particular device pleases a particular reviewer in a particular circuit tells us nothing about why or what we are likely to find if we use it in another circuit ourselves. To anyone wanting to design an amplifier, these articles seem worthless to me.

[kimberley]

Discussion about the virtues, values & volumes (physical) of different capacitor types has been a long-player!

John Wright of IMF wrote back in about 1970:

"At various times criticism has been levelled at the use of reversible electrolytic capacitors and ferrous-core inductors in crossover networks. Electrolytic capacitors have been said to became conductive during tunes of operation causing 'transient overload', whilst cored inductors have been said to 'ring'. Despite the fact that at the lower impedances and crossover currently frequencies employed, paper capacitors and air-cored coils would be completely impractical in terms of coat and space, it was decided to conduct some research into the matter to determine what, if any, subjective benefits were to be gained. Using a multitude of ex-Government block paper capacitors and chunky, air-cored hand-wound coils a switching arrangement was made up whereby a direct comparison, between the test sample and a crossover entirely comprised of electrolytics and ferrous-core inductors, could be made. The same drive units and enclosure were employed with adjustment for differing insertion losses but, that apart, the networks were as identical as possible and, not surprisingly, the overall balance remained unaltered. There was, however, a marked difference in the 'attack' and 'cleanliness' of the sound particularly at very high and very low listening levels where transient peaks were encountered, and in every case the more 'inconvenient' network was preferred. This led to examination of the toneburst response and distortion components at various levels and frequencies. Here the differences observed could have been explained by errors in the test procedure or tolerance differences of the components used, or even a subtly different load presented to the amplifier. Again, we appear to have encountered a situation where the ear is a more reliable tool than the equipment available or knowledge of how to effectively employ it!

As the intention behind the project was to develop a loudspeaker where performance, rather than price or an operating principle, was the primary criterion of merit, the choice presented itself between adopting the superior network and increasing enclosure size to accommodate it, crossing over at a higher frequency to make it more manageable, or continuing research to discover what factors precisely were contributing to the difference, and then eliminating their effects. Since a higher crossover had previously been discounted for reasons mentioned, the latter course was adopted. From the work it was found that if the tuned circuits employing ferrous-core inductors were of comparatively low Q, their substitution for the air-cored brought a negligible change which could not be detected when employed with electrolytic capacitors. Secondly it was found that by far the most critical capacitors were those feeding the tweeter and super-tweeter, which did require effective 'blocking off' on transient pulses. Comparison between the air cored coil and paper capacitor network, and a crossover comprising both types of capacitor, according to their location, and lower Q ferrous core inductor circuits was entirely favourable, the differences being rather less than could be expected from sets of components subject to normal manufacturing tolerances. Furthermore, when differences were noted, opinion varied as to which network was preferable, and this was partly (for reasons too involved to discuss here) because the components adopted presented certain other advantages if used in the fairly conventional configuration..."

The whole article is on the IMF enthusiasts' 'site at:

http://www.imf-electronics.com/jwright/hifinews0770I.html

which some may find interesting if only because at the time AR & IMF may have been viewed as competitors in the same market.

My own view? Well, I have both IMF & ARs and I like them both. When rebuilding crossovers I use modest-priced polypropylene capacitors for most purposes, but reversible electrolytics ("NPEs") for low-frequency circuits, where bulk - & expense - mitigate against polypropylene. Then I hedge my bet with a small polypropylene bypass capacitor. But of course I am English and compromise is part of our character!

Adam K.