Well said! There are certainly some snake oil peddlers out there. One I recall was Kimber Caps. Although they were a good capacitor, they were not special in any way. They were a polypropylene & foil tape wrapped and epoxy endfilled, with stranded teflon coated wire. They claimed all kind of "sonic benefits" but the bottom line is they were a .50 cent film/foil capacitor.
I know the company that manufactured these for Kimber, they are a quality house. It was the market hype to was hard to swallow
Sy,
Thanks for sticking up for me, I assume that he has no idea that I have been involved in plastics manufacturing for over 35 years, but I'll give him a break there. Now that comment about the 25% rejection rate that sounds rather difficult for any of us who do serial manufacturing to understand. That is just unacceptable QC in any area that I have worked in for a long time now. I would never say there is absolutely no differences between the varied manufacturers of caps but that is not what we have been saying. Take a well made cap with similar film properties and the same type of process, metal/film let's say, with equal electrical values, I keep saying that but it guess that gets by, and show us that you could really hear a difference between the two in the same exact position in an electrical circuit. Compare a radial or axial cap with the same voltage rating and the same type of construction and let's see this wide variation in electrical results we are forever hearing about?
Thanks for sticking up for me, I assume that he has no idea that I have been involved in plastics manufacturing for over 35 years, but I'll give him a break there. Now that comment about the 25% rejection rate that sounds rather difficult for any of us who do serial manufacturing to understand. That is just unacceptable QC in any area that I have worked in for a long time now. I would never say there is absolutely no differences between the varied manufacturers of caps but that is not what we have been saying. Take a well made cap with similar film properties and the same type of process, metal/film let's say, with equal electrical values, I keep saying that but it guess that gets by, and show us that you could really hear a difference between the two in the same exact position in an electrical circuit. Compare a radial or axial cap with the same voltage rating and the same type of construction and let's see this wide variation in electrical results we are forever hearing about?
capman57,
Your observation is the same that I have spoken of. Many so called audiophile caps are nothing but a pretty wrapper and a different lead out wire. I have seen the same thing for other name brand caps and this is what some of us are talking about. Why pay $5.00 and more for a cheap film capacitor when it is just a normal cap?
Your observation is the same that I have spoken of. Many so called audiophile caps are nothing but a pretty wrapper and a different lead out wire. I have seen the same thing for other name brand caps and this is what some of us are talking about. Why pay $5.00 and more for a cheap film capacitor when it is just a normal cap?
I am assuming that you have visited many capacitor manufacturing facilities and and have experience with commercial vs. aerospace vs. military and acceptable yields and end customer requirements. I don't recall stating "end customer yields" at 75%. Most commercial end users don't give a rip about factory yields, provided the MTBF for their application is adequate. Acceptable yields in a manufacturing company are part of the business model, that is, what's acceptable and what isn't, provided there isn't a customer requirement.
For example - lets discuss a product that gets a lot of mileage - PIO (paper in oil). To start with that is a bad acronym - if there is paper in part of the dielectric, then they has to be vacuum impregnated. To a manufacturer, PIO lends itself more towards "oil filled". Most impregnated or oil filled capacitors are leak checked, to insure that the end customer doesn't get defective products. Depending on the type/style of capacitor, the environmental requirements, leaks are not 100% preventable during production and a certain rate of failure is accepted based on end customer requirements, MTBF, and business model (P & L). On the opposite spectrum, we manufacture products that get 100% inspected at various stages of manufacture, and only a certain failure rate is acceptable to the customer.
So what is a commercial product? That could be a very deep discussion, so let me outline it for you with an example. Many years ago Motor run & Motor start capacitors use to be larger oil filled units. One might say, technology has changed is why they are smaller. The answer is not really. The raw materials used for capacitor manufacture have not changed for 30 years - there are some subtle changes, thinner dielectrics, slightly better manufacturing techniques, etc, but essentially the same. What I am saying? The MR/MS industry was driving price down and the only way to do that was by decreasing life expectancy. So thinner dielectrics were used, oil was left out (for the most part) and life expectancy was reduced to 25K or 40K hours from 100K.
A commercial product is manufactured as cheap as possible while still meeting basic needs. Military & Aerospace are very different.
My comment about material science is correct - when someone states "willy nilly" differences without understand the implications of the "willy nilly" differences, they obviously don't understand material science. These small differences can make a huge difference in the application.
Hand made & semi-automated - you are easily amused 🙂 Have you ever seen a fully automated radial lead capacitor operation? This is fully automated. You dump windings and cases into a vibrator feeder, load up the epoxy and lead wire, flip the switch and 15 minutes later parts start popping out. ANY capacitor manufacturer that is not a high volume nickel & dime house uses a mix of hand processes, combined with semi-automatic processes. Most of the USA capacitor manufacturers are no longer high volume houses and mix hand operation with automated operations. Obviously (unless you've been to a mfg) everyone imagines what "hand operations" actually is, differently. Most people visualize some person cranking a handle to "wind up" the capacitors. This is far from the truth - hand winders are really semi-automated devices. They still have tensioning, turn or length counters, ramp up/ramp down controls. The difference is each capacitor is started and removed by hand.
If anyone would like an education on capacitor manufacturing, please feel free to contact me and we can arrange for a plant tour.
Yes, thus my comments.
If we were getting 75% manufacturing yields, we wouldn't be in business; this would be a huge ding in customer quality audits, especially our automotive and medical customers, and essentially eliminate any reasonable margin. If a major cap manufacturer actually had 25% scrap, I could get rich fixing it.
Okay - fair enough statement. I have not only been in the "plastic industry", but been involved in the design, manufacture, installation, and training of film metalizers, extrusion lines, vacuum plasma treaters, atmospheric plasma treaters, and corona treaters for 14 years. I have been in facilities all over the world, including some of the premier mfg's such as duPont. I spent 7 months in the Luxembourg facility (Teijin - Polyester film for capacitors) commissioning a new process.
I've read a few posts with negative comments about "trade secrets" - yes there are some proprietary processes that capacitor manufacturers have and I won't share them here and neither would any of you if you were in my position.
I will try to answer best I can. First I need to say, in the audio industry as a whole, its very subjective. Forget high end audio, go to the big box stores and have various people listen to equipment and you get different opinions.
So, here we go. One process that is required after winding is annealing - or thermal setting of the plastic. How this is performed has an effect on the capacitor mechanically as well as electrically. I have not addressed the EMF as of yet but now I will touch on it. When a film capacitor is charged and discharged, the winding "moves". How much it moves is dependent on the shape (round, flat, etc) and the annealing process. How does that effect an audio circuit? That is where "you" are the experts. I can tell you that when a capacitor is charged, it constricts and the capacitance changes. Shape (cross section) has a tremendous affect and oil also dampens the effect.
I would venture to say the ESR & ESL have a big effect on the sound of capacitors. I did mention in my last post "I have not been on this forum very long", so therefore have not hear much about those two parameters.
Sorry I don't have much time to go on with this. I will pick up later 🙂
No doubt I agree with you, that is, within certain markets. Have you been to a capacitor manufacturing facility in China? I'm talking about down & dirty commercial product, not auto or medical industries.
Perhaps my 75% was more of an emotional response, but rest assured generic commercial grade capacitors do not have high yields.
Well-known stuff, but that's why it's good to have caps wound on machines with high tension. And that also why the slight electrical superiority of PTFE (popular with fashion audio types) for timing circuits is compromised by poorer mechanical properties- you can tension, for example, a biax PP film to a much greater extent. COC even more so, but for whatever reason, that material hasn't found much industry use.
Not down and dirty ones- they wouldn't ever be on my list for potential suppliers. Wima, Vishay, Sprague (back in the day), TRW (ditto), Panasonic, CDE, those sorts of companies would be.
I totally agree (now we are getting some where). I've been in this audio capacitor industry back in the 90's before it became crazy. Many companies market parts based on emotions. We manufacture for some of those companies 🙂
On the other hand, we also supply good quality product without snake oil - actually we use FDA grade mineral oil. I will do my best as time and confidentiality permits, to continue to give facts and try less emotions
Just curious- since I rarely use any caps with oil- why FDA grade rather than just high purity? And why mineral oil rather than synthetics, especially fluorocarbon-based synthetics?
I can't speak for all of these companies, but I can tell you some of them are now producing in China using Chinese materials. One of the companies you mentioned just moved part or most of their facility to Mexico - so expect some changes there.
Sprague (now Dearborn) and TWR (now ASC) are quality manufacturing companies.
As you probably well know, if you purchase a 5 cents part, then that is what you get. I'm guessing you are in some type of electronic industry that supplies to the automotive and medical industry. Based on that, I'm guessing the components you spec have certain requirements they must meet, possibly over and above catalog items. Perhaps even source controlled?
Excellent question - part for marketing purposes (ug). When there is fluid of any kind involved, people get really nervous. We chose to use FDA grade because you can eat it. If there is a problem with the parts or if the customer mis-handles them and oil leaks, it can be wiped up a disposed of easily.
One issue with impregnation fluids is vapor point and cost. Many fluoro's have low vapor points and boil off. Many companies use silicone, castor, and various plastizers. Using high purity has benefits but when its used with paper its kind of a mute point.
I was in electronics and aerospace, but not any more. These days, I work for a company that supplies mostly to heavy manufacturing, automotive, aerospace, and medical. Not only do our products have to meet high standards, but so do our manufacturing and quality systems. The supplier audits we get are the closest thing I know to proctology. Just finished a two day audit from a major pharma company, and I still can't sit down.
Thanks for the answer about FDA- as a cynic, I'm not surprised. 😀 I was thinking of high MW fluorinateds (yes, I know they're expensive) and controlled MW aliphatics.
Sy,
If you used some aromatic oils you could make such a sweet smell as your amp is warming up. just put a small vent in that electrolytic cap for ambiance!
If you used some aromatic oils you could make such a sweet smell as your amp is warming up. just put a small vent in that electrolytic cap for ambiance!
You obviously have an impressive back ground of knowledge 🙂
Like I stated before, I'm new to the forum, so I don't know if EMF in capacitors is well know. That is why I stated it.
I agree in principle to your high tension statement, but its not that easy. EMF can be reduced by annealing and often better, vacuum annealing. High tension winding also reduces corona on-set (less gas to ionize). I would venture to say a capacitor manufacturer does have SOP's to wind at max tension at all times.
Several things comes into play - what is the actually application? What type of winding or winding machine is it? If its a split mandrel, then tension has to be carefully considered so that the mandrel hole doesn't not collapse, thus causing additional electrical problems. Is it an impregnated part? where it becomes very tricky is on thin films, especially BOPP. Any stretching of the film not only risks damaging the film, but micro-crack the metalization.
Sophisticated tensioning primarily is due to high speed winding. I'm going to assume you've seen a Metar or Arcotronics winder. Running at top speed these things are impressive. In all manufacturing the key object is to get as much out as possible in the shortest time possible. So that said, these winders are high speed, but they have a cycle. The cycle requires ramp up from some slow speed, and ramp down. This is where tensioning is very important. Minimizing the ramp slopes and maximizing the winding speed is key to getting products out the door.
Regarding COC vs. BOPP - my guess is that COC is not available in thin gauges. BOPP is available as low as 3 um and PET 0.9 um I'm not too familiar with COC, but perhaps is a cost issues as well. In my experience, PTFE as a capacitor dielectric has vastly suppoerior electrical characteristic to that of BOPP, but a you pointed out, mechanically its a real bummer
Capman57,
I never paid much attention to the manufacturer's name on the winding machines that I saw but do believe that units I saw were not very new in manufacture date. They did do some semi-automated winding when the volumes were low but most of the time they were using full automation when making large runs of single values. I would imagine that the newer machines would be highly accurate as regards to winding tension, not sure why it would be different at different speeds but I will accept that fact if you say so.
I specifically remember that the owner had a preference for German made PP film in his factory. I wouldn't think there would be very many manufacturers of this type of film as it is so specific in its use and so must be limited to a few manufacturers around the world. Now you throw in the lower dollars Chinese suppliers and I can imagine that there could be quality issues but that would be something that would probably be for more common +/- 20% type of capacitors and not the 1 and 5% values we are mostly talking about here.
I'll leave the technical arguments to you and Sy as I don't have enough information to stand on besides what I have personally seen. Major audiophile brand names made with cheap 25 cent capacitors and nice pretty wrappers and braided Teflon coated lead-out wires. Oh yes they also changed the color of the epoxy that they used to encapsulated the ends.
I never paid much attention to the manufacturer's name on the winding machines that I saw but do believe that units I saw were not very new in manufacture date. They did do some semi-automated winding when the volumes were low but most of the time they were using full automation when making large runs of single values. I would imagine that the newer machines would be highly accurate as regards to winding tension, not sure why it would be different at different speeds but I will accept that fact if you say so.
I specifically remember that the owner had a preference for German made PP film in his factory. I wouldn't think there would be very many manufacturers of this type of film as it is so specific in its use and so must be limited to a few manufacturers around the world. Now you throw in the lower dollars Chinese suppliers and I can imagine that there could be quality issues but that would be something that would probably be for more common +/- 20% type of capacitors and not the 1 and 5% values we are mostly talking about here.
I'll leave the technical arguments to you and Sy as I don't have enough information to stand on besides what I have personally seen. Major audiophile brand names made with cheap 25 cent capacitors and nice pretty wrappers and braided Teflon coated lead-out wires. Oh yes they also changed the color of the epoxy that they used to encapsulated the ends.
I fully understand this - we are starting to consider AS9100 and can't wait 🙁
Funny story - many years ago I stumbled across some fluorinated fluid. Did a little research and found it had very desirable characteristics. Decided to impregnate some capacitors and the following day I opened up the chamber to find all of the fluid gone. Vapor pressure 🙂
We have a mix of 70's & 80's machines and a few from 2012. It all depends on the product and volume. Some of the more sophisticated machine take time to set up and for small runs we use the old machines. We might even have an old Kresslor (1950's) in our warehouse 🙂
German polypropylene - Thats easy - Steiner films. They have two facilities, one in North Adams Ma, and the other in German. They have the best capacitor grade polypropylene period. They are also the top metalizing house in the world - my humble opinion.
Thanks for the marketing tip!! We could come up with seasonal smells as well 🙂
- Status
- Not open for further replies.