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In Reply to: Re: What is wrong with Auricaps? posted by Jim McShane on March 3, 2007 at 10:23:11:
Actually it wouldn't because mundorfs are polypros and not paper in oil so again that just implements what I'm saying.
You said "The biggest problem with auricaps is they are metallized polypros".
So are many Mundorfs.
I have seen the insides of a few metalized caps. There is a wide variety of metalization thickness. There is also a means of dividing up the plates into a bunch of fairly safe, individually fused areas. That kind of cap is quite varied in its construction. I just don't believe that one would be able to say something useful about the whole family. Given the good results I have gotten from MKV oilers in coupling cap applications, I will continue to believe that it's possible to make good ones. I have just the opposite experience with the Solen metalized offerings( which is contrary to a bit ov experience posted here ). The decisions on which cap to use are most closely equated to which Church shall I become a member of think.
A brief story. I bought some Mundorf silver supreme for a crossover application. The results were very good. Then I ordered a pair to try in home built SET amps. Not a good move. They sounded horrible.
I happened to buy two AEON polyprop and tin foil caps when ordering the Mundorf just because the vender was flushing them at low cost. After hearing how bad the Mundorfs were (in this RC application) I removed them and installed the AEON to see how they might compare. The AEON were far and away superior. Upshot? Predicting performance of a single component part may not be possible. It always comes down to how does it sound versus expectation, reputation, and other performance related info/hype/scuttlebutt. That said, I know where Mikey Samra is coming from regarding metallized film caps. I don't think metallized film caps sound as good as film & foil in RC coupling. Each to his own.
At the risk of getting involved in an un-resolvable difference of opinion...If you read carefully what Mike wrote, he's really describing his dislike of the polypropylene dielectric and not whether conductors are metalized or film-n-foil. He's also stating that oil impregnated paper dielectric is superior to PP and so I'd also expect him to not grant any great favor to the "AEON" (AXON?) caps either. The SBE 715/716 series of caps is also film-n-foil and yet most true believers are passionate in their dislike of them so it's not just a materials/construction thing.
Mike cites as one of his reasons for likeing paper/oil is that they're more linear with frequency or something like that. Actually, in terms of pure objective measurements, polypropylene is a near ideal dielectric in most every way and much better than paper. Obviously, there's more to cap preferences than objective measurements.
I use polypro caps but I use them as power supply filter caps where we are dealing with one frequency 120hz but thats me.
The pio caps I speak of in the vit Q or the k40 are very expensive caps that the US or Russian Military paid dearly for and I have a price list here from 1953 showing where the us military paid 22 dollars for a single .015 at 600vdc cap.Now thats quite a bit of money even today for most people let alone 1953 where it would be in the neighborhood of 105 dollars per cap if sold today. Had these caps been made cheaply by a factory with no attention to detail or tolerance and just basic materials,they may be just a so so cap.
Anytime the military has something made its usually top notch.When I talked to rel cap and the one engineer is telling me that he uses k40s in his amps,it made me realize that they must be somthing to behold being the access he has to caps himself.When he told me they could build a cap like the k40 and this was the .1@630vdc cap for 135usd,I thought what a bargain at 4 or 5 dollars each.The big price was already paid for these caps and now we are buying them at surplus marketing cost or maybe they are hot,who knows!! At any rate when I see parts connexion selling a a pio cap for 1400 dollars each,I wonder how much better it is if any.
Steve like you said and basically everyone else says,if we rely only on specs,we will wind up with a diversity of opinions and maybe none that we like.I guess its buy what you like but being I have a hand in the vta board with upgrades with roy mottram,I know the difference the k40s make in that board.
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