[art]

But when did that ever stop me?

It does not take a tremendous amount of experience, knowledge, intuition, creativity, or even chutzpah, to take cheap shots at someone else's work without any factual basis.

Well, ok.....maybe it does take some chutzpah, but certainly not much or even the kind I would advise.

I suppose guys like John Curl and Walt Jung decide to put their professional reputation(s) on the line, for no good reason at all. Other than to have others who do not take the time to try to comprehend their efforts take cheap shots at them. Even if one does not agree with their conclusions, the position of a professional would be to appreciate the tremendous amount of work necessary to put forth their assertions.

OK, now I'll stop. For a while.

Pat

[TheChairGuy]

OK, now I'll stop. For a while.

Pat

Thanks, Pat 

[fortitudine]

The "non-perfection" of a capacitor is measured by the dissipation factor. Every real capacitor has a significant and measurable dissipation factor. Just pick up an LCR meter. I just bought some caps for a new crossover and measured them. The nice 100uf polypropylene has d=0.02. The 330uf non-polarized electrolytic has d=0.15, roughly a factor of ten difference. But you could not see this difference on an oscilloscope.

So you can easily measure an objective quantity that correlates to the "goodness" of a capacitor. How does it sound? That is, as always, subjective.

Randy

[Scott F.]

Hey John C. (if you are still with us), I've got a question I've always wondered about. Let me start by letting you know I'm into tubes primarily.

As you know well there are all kinds of exotic caps being used in tube amps, pre's and even crossovers. After playing with numerous caps in the coupling position (and elsewhere) I've found that really like the sound of the Teflon V-Caps and in the right location (and design) the OIMP's.

Why is it that the exotic caps seem to be only used in tube amps and such and not solid state gear (save power supply bypassing)? I haven't seen anybody try to stuff any of those on board in the coupling (or any) position.

Is it the forward nature of a transistor doesn't mate well to revealing nature of these type caps? Is it a size issue? Or is it designers just think it is overkill?

[Bill Baker]

Hey Scott,
 Actually, there are a few SS amp designers that have seen the benefit of exotic caps in their designs. I won't mention any names but I know of one manufacturer who has V-Cap Teflons all through his personal amp. They are not installed in production units as it would blow their $3k retail price point.

 In many SS designs, the values used are far too large to accomidate Teflon or even other quality film caps. Also, size restraints would prevent large physical capacitors on the circuit boards of most designs.

 That's all I'm saying in this thread as I do not want to be involved in this debate.

[Imperial]

Anyway...
I'm not gonna say that I don't get Daryls side of things, because I do.
I think a lot of us do, Even Curl, when you get down to it.
But reading the textbook and doing the stuff on school, becoming an engineer.
You ain't done when you get your diploma!!! That's when you start to learn!!!
To not speak so quickly among those things also...

I've gone to school myself, mechanical engineering, and yeah, after that is done, you feel you know it all.
You know it ALL ... But it ain't so...
Even after a number of years doing stuff, working, gettin' it right even... You ain't done yet either!!!
Getting the experience, "growing up" as it were, understanding that square is 4 times a left turn, and then you are back at the start.
But now you have traveled...

Get it?
Nice...
Don't sweat it Daryl, we've all been there... I know I have! 
I'll say, Curl posting again after 4 years...
I guess he's passionate about capacitors then!

- The best capacitor.. Who cares? If it does the job, it does the job... Thats my take on the matter.
You have a speaker manufacturer named Boenicke Audio, that makes some filters that are filled with all sorts of knowledge and parts, and Boenicke uses what I believe is the best capacitor. The DCA "flat pack".

I also think that the ears get the last word... when sound quality goes.
Science, isn't an exact art if that is what is believed,  or so is the current theory, until something better comes along.

Imperial

[Mike B.]

let me chime in on the Vishay caps. I have a supply of the 1837's I purchased from RS. This is the 1% tolerance, 100 volt variety. I read about them on a multi capacitor test done by a individual in Europe. I find them to be of the highest audio quality. They simply open up the sound IMO. They also make a excellent electrolytic bypass IMO.

[john curl]

Scott, many expensive and exotic audio designs use Teflon caps.  In fact I have 2 samples in front of me at the moment:  One is called 'Audio Cap', and is .33uF Teflon.  $41 each at OEM prices. 
Another is a Russian made .1uF cap that is the best made cap I have ever seen.  However I haven't measured or listened to it. 
Now why TEFLON?

Teflon is simply the most accurate cap that we know of, except for an air or vacuum cap. 
This has been known for more that 50 years, and was first important when we used analog computers for computation as well as digital computers.  The deviations that caps made from being an 'ideal' cap changed the final results, so Teflon was often specified and necessary.  Next best was polystyrene. 
In the tests that Walt Jung and I presented, we were trying to show that many cheap caps did not follow their presumed and assigned path when passing audio signals.  This is called 'linear' distortion, rather than 'nonlinear' distortion that we are accustomed to measuring. Does 1 to 10% deviation from the ideal path make a difference?  How about 3-10 caps in series, each adding their contribution?  Sooner or later, something has to make a difference, so we published some results using a differential comparison developed by Scott Wurcer of Analog Devices for the test.  Any engineer or technician could emulate our results, either by making a test box, or by emulating 'real' capacitors on a computer and differentially cancelling it by subtracting an ideal cap using a transient analysis program.  You get essentially the same results.  Those of you in doubt, check it out for yourselves. 
It is interesting that our simple test procedure, while measuring differences between caps down to .001%, cannot differentiate between Teflon, polystyrene or polypropylene to any extent.  However, we still hear small, but important differences when these caps are used in the best audio equipment.  This is especially true in RIAA eq networks, where the caps must drop AC voltage across them. 
Coupling caps between stages, or power supply bypass caps may or may not benefit much from Teflon.  Polystyrene may be OK in many cases and even Polypropylene.  However, everything else should be suspect, for good reason.  It can be easily measured to deviate from ideal.

[Imperial]

Mr Curl
I gather then, that to get accuracy, teflon is better, but not nessesary the only way, as
finding the right cap for the right place is also a part of the trade...
As for Teflon being the most accurate, ok...
Is there something to be said of the word that Teflon caps need some 400 hours to Burn in?
Or does this imply another aspect of the design, that is burning in... when connected via Teflon..?

Imperial

[john curl]

Imperial, I would stick to polystyrene, if I were you.  If you want to 'sweeten' the sound, then Mylar might be a good choice.  Break-in is something that I hate, but seemingly necessary.  I don't know what the hours are. 
For the record, most electrolytic caps are still used with zero DC volts across them.  Just look at mid fi equipment, sometime.  This is how they make coupling between op amp stages, without using servos.

[Scott F.]

I may be talking out of my rear end here but from what I've read, Teflon has the best dielectric constant of the materials used in the production of caps. Here I'll dive off into the deep end, is the reason for the long burn in (which I've experienced many times BTW) due to skin effect and the slight changes in the dielectric materials (ie, Teflon takes longer than the poly's)?

So John, are you considering using Teflon's in some of your upcoming designs? If so (as Bill Baker mentioned), have found a source for the smaller value caps typically used in SS designs?

[john curl]

I have a T mod for the original Vendetta, and we tend to use Teflon these days. 

[Daryl]

Daryl, what gives you the right to form an opinon about capacitor problems?   This better be good!

It does not take a tremendous amount of experience, knowledge, intuition, creativity, or even chutzpah, to take cheap shots at someone else's work without any factual basis.

No cheap shots here.

I think I made some good points.

[TONEPUB]

I guess what I'm interested in is what your background is?

Do you design electronics?  What kind of scientific credentials
do you have....

[Daygloworange]

Am I the only one wondering why there is not more elaboration here on capacitor perfromance in electronic circuits despite the parties already involved in this thread seeming to have more than enough areas to talk about in order to make their respective views?

Inquiring minds want to know...

Cheers

 

[Imperial]

Daryl, what gives you the right to form an opinon about capacitor problems?   This better be good!

It does not take a tremendous amount of experience, knowledge, intuition, creativity, or even chutzpah, to take cheap shots at someone else's work without any factual basis.

No cheap shots here.

I think I made some good points.

If you gotta paint...

You gotta paint...

The right way is up top there...
 
Uhm , and then there was something about corners being the most important? About capacitors?
Well, I don't think we should paint that...

Imperial

[ctviggen]

he made the following "points":

Film capacitors are nearly perfect componets (especially polypropylene and teflon, polyester is much less perfect but still impressive).

There are differences but too small to hear since the componets are so nearly perfect.

Also the influence of a capacitor is strongest at the corner frequency of the circuit (declining above and below) so in most applications (coupling, bypass) you can eliminate the capacitors influence by locating the corner frequency well below the audio band (use a large value) making even poorly performing capacitors have no signifigant effect upon the circuit.

The article you linked as well as the articles from Jung/Marsh and Jung/Curl are utterly foolish.

They spend most of their time showing you the operation of capacitors you would never use for audio.

Then they waste more time operating polarized capacitors reverse-biased/unbiased which even a novice knows not to do (but apparently not them).

Finally they draw conclusions which their own measurements don't support.

[ctviggen]

What can one learn about the following:

http://members.aol.com/sbench102/caps.html

Not much, considering they tested at a measly two frequencies. 

[john curl]

Daygloworange, it is not necessarily easy to give detailed info to a general audience.  The original papers on dielectric absorption come from the 50's and 60's, and are really the best references.
Audio manufacturers ignored this problem at that time, except by accident, such as switching from wax paper caps to Mylar, that Marantz did in the early days.  There actually is a significant difference in DA between these two types.
When it comes to newer and better caps, my first experience was with Mark Levinson (the man) back in 1973.  He was using polycarbonate (somewhat better than Mylar) caps in his designs.  He found that they sounded better.  Then, in 1974, I saw my first real measurement of nonlinearity in caps.  This was done by Tektronix, and it was an eye opener.  However, it only showed that ceramic caps (a common coupling cap at the time) were prone to distortion.   Later, I found that Tantalum caps operating at 0 Volts (typical design decision for about a decade) were also prone to distortion.  I published a paper with the IEEE on this in 1978.   This is when Walt Jung first learned of non-linear distortion measurement in caps, at least that is what he told me.  
About the same time Dick Marsh (then working at Lawrence Livermore Labs) realized that DA could be important, especially in the tantalum caps that we all used at the time.  He got together with Walt Jung to write their fundamental paper on cap selection around 1979-80.  
In subsequent years, Bob Pease wrote a very good paper on DA, and finally Walt and I wrote a paper on how to easily measure DA and note how significant it could be, at least as a measurement difference.  
Most of us, designed out coupling caps where we could, because 'good' caps cost big money and are very large.  Servos helped us in a big way, to remove interstage coupling caps, but you will find that most mid fi equipment still just uses electrolytic caps at essentially 0V between stages or in the feedback loop.  This is something that Daryl doesn't seem to know about.

[art]

You mean like:

Film capacitors are nearly perfect componets (especially polypropylene and teflon, polyester is much less perfect but still impressive).

Nearly perfect, but not perfect. So what does this statement prove? Anything that the average designer does not already know?

There are differences but too small to hear since the componets are so nearly perfect.

So he says. But no proof to back it up. Just his opinion.

Also the influence of a capacitor is strongest at the corner frequency of the circuit (declining above and below) so in most applications (coupling, bypass) you can eliminate the capacitors influence by locating the corner frequency well below the audio band (use a large value) making even poorly performing capacitors have no signifigant effect upon the circuit.

That is going to be a hard sell. "Poorly performing capacitors have no significant effect..........."

The article you linked as well as the articles from Jung/Marsh and Jung/Curl are utterly foolish.

Well, certainly an erudite opinion.

They spend most of their time showing you the operation of capacitors you would never use for audio.

Oh, and just what capacitors are used in audio?

Answer: In commercial gear, whatever they can get. The cheaper, the better. But he just told us that "poorly performing.........." 

Yeah, whatever, dude.

Then they waste more time operating polarized capacitors reverse-biased/unbiased which even a novice knows not to do (but apparently not them).

Oh, so now it is not only the entire audio industry that uses electrolytics in circuits with only AC across them that doesn't know what they are doing (well, he may have a point........), but the now the guys who show not to do it are also less knowledgeable than a novice. Because they show what happens when you do. Boy, that makes a lot of sense.

Finally they draw conclusions which their own measurements don't support.

So, measurements that show don't use an electrolytic with only AC across it is bad, because "our expert" says that even a novice knows better, but their measurements don't support that conclusion.

Yeah, right.

I see no points, just a lot of hot air. From someone who appears to have an agenda against someone who has experience and the respect of their peers.

BTW, who are his peers? And do they respect him? Where is his anthology of work, and where can it be found?

All for now......I gotta make a $ or 2. Have fun, and play nice.

Pat