I'm not writing them off. I'm just trying to find a technical explanation for the observations.
It's a fact that polyester is the poor man's polypropylene. But it's probably "good enough" for most of the audible spectrum. Besides, some people just don't like having lots of detail in the high end. For instance, I have a friend who's heavily into Hip-Hop, and he hates the sound of a really good stylus on vinyl. In his ears only a blunt DJ stylus sounds "correct".
It's a matter of taste.
I wouldn't waste my money on Mundorf silver caps though. I'd be perfectly happy with Wima caps or some equivalent with tighter tolerance.
It's a fact that polyester is the poor man's polypropylene. But it's probably "good enough" for most of the audible spectrum. Besides, some people just don't like having lots of detail in the high end. For instance, I have a friend who's heavily into Hip-Hop, and he hates the sound of a really good stylus on vinyl. In his ears only a blunt DJ stylus sounds "correct".
It's a matter of taste.
I wouldn't waste my money on Mundorf silver caps though. I'd be perfectly happy with Wima caps or some equivalent with tighter tolerance.
mach1,
brilliant comments. I would only add what the fat man said - all theory should come from practice.
Wima caps - every time I have replaced Wimas, the sound gets better. There is so much 'received wisdom' aka b/s in audio it's breathtaking. Mosfets sound better when run hot - to make that a rational statement you have to have run them by way of fan cooling which means at room temperature - I have and they sound more detailed and more organic and this way they don't heat up the other components. I have never seen a single comment about mosfets on this point where the author has said that they have done any tests at all to prove their point.
el donkey - interesting comments about using low value K73s' as bypass. I like your kind of posts because they come from practice. I am rebuilding a hybrid amp and have fitted 3.3uFs, so I may try to get hold of some caps at or near the values you have used and see if bypassing yields a better sound.
From listening to the difference that 1uFs made as input caps, I'm not sure that I would attempt to bypass these as I found the sound to be just 'right' - if it aint broke don't fix it'.
brilliant comments. I would only add what the fat man said - all theory should come from practice.
Wima caps - every time I have replaced Wimas, the sound gets better. There is so much 'received wisdom' aka b/s in audio it's breathtaking. Mosfets sound better when run hot - to make that a rational statement you have to have run them by way of fan cooling which means at room temperature - I have and they sound more detailed and more organic and this way they don't heat up the other components. I have never seen a single comment about mosfets on this point where the author has said that they have done any tests at all to prove their point.
el donkey - interesting comments about using low value K73s' as bypass. I like your kind of posts because they come from practice. I am rebuilding a hybrid amp and have fitted 3.3uFs, so I may try to get hold of some caps at or near the values you have used and see if bypassing yields a better sound.
From listening to the difference that 1uFs made as input caps, I'm not sure that I would attempt to bypass these as I found the sound to be just 'right' - if it aint broke don't fix it'.
Hi,
Polyesters caps distort. Audibly so and measurably so. End of story.
Any added superior cap bypassing it proves exactly that point.
Cheers,
I know. I was just trying to be a bit diplomatic
Yes, but there's also tons and tons of alchemy and superstition.
There's no reason why this:
should sound any better than this:
I have a feeling that the fact that it's shiny and have been called "military surplus" is enough to get some mind tricks going.
It's most likely pure make believe. But in audio make believe is often more real than reality, so I guess it's all cool.
Yes, everybody who has tried and likes them has been deluded 'cos they're all shiny and purdy, and that military surplus mystique really sucks them in at the subliminal level. Thanks for pointing this out. I shall dislike them intensely from now on as polyester caps obscure top end detail.
Moreover I will never ever make the mistake of trying to actually compare capacitors by listening again and will only read specifications which tell me the best ones to buy.
Now that all this nonsense about these caps sounding good has been put to bed once and for all, why don't we just close the thread and leave the matter as a valuable lesson learned.
Moreover I will never ever make the mistake of trying to actually compare capacitors by listening again and will only read specifications which tell me the best ones to buy.
Now that all this nonsense about these caps sounding good has been put to bed once and for all, why don't we just close the thread and leave the matter as a valuable lesson learned.
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Yes, when used as filters.
But we are discussing coupling capacitors here. Coupling capacitors when sized appropriately do not filter the audio frequency, they do not have a significant audio voltage across them and as a result they do not distort the audio frequencies.
mixing dielectrics may have some advantage. To date, my limited researches have not found any article/paper that describes what dielectrics can be used to compensate for shortcomings in the parameters of the main (largest value) coupling capacitor dielectric.
@mach1
I get what you're saying. And I'm not dismissing PETP caps. There's a good chance that they simply mess up the sound in a way that's pleasing to the ear. Like tube amps and vinyl.
Audio is a highly subjective thing, but it still doesn't make sense to rely solely on listening tests. You get the best and most effective results when you rely on a good balance between logic and emotion.
My biggest gripe with this thread is that the PETP caps are being compared to all kinds of caps with other types of dielectricum.
It would make more sense to compare them to other polyester caps.
I get what you're saying. And I'm not dismissing PETP caps. There's a good chance that they simply mess up the sound in a way that's pleasing to the ear. Like tube amps and vinyl.
Audio is a highly subjective thing, but it still doesn't make sense to rely solely on listening tests. You get the best and most effective results when you rely on a good balance between logic and emotion.
My biggest gripe with this thread is that the PETP caps are being compared to all kinds of caps with other types of dielectricum.
It would make more sense to compare them to other polyester caps.
There's no reason why this:
should sound any better than this:
...
Plenty of reasons - the construction differs considerably. One is axial, the other is radial. One has cylindrical winding, the other has elliptical winding. One has a stiff aluminium housing and epoxy seals, while the other has no outer housing. One has non-magnetic leads, the other ?
You get the general idea - I have not even gone into the details of the contact weld between the leads and the metallization, which is critical for good sound. Simply wrapping the film around the leads and hoping for a good contact won't cut it.
I have never seen an actual commercial capacitor built that way. Anything that comes from reliable manufacturers like Vishay or Wima uses thermally sprayed metal.
The theological discussions are amusing, though.
I measured the tan(delta) on a K73-16 1.8uF/100V at ~0.1%.
A typical polypropylene would be 0.01 to 0.001 - below the capability of my measuring setup.
However, a Black Gate PK 4.7uF/50V measures around 1 to 2.5%, about the same as most small electrolytics.
I do not detect any audible high-frequency drop-off with the Black Gate PK as a coupling cap.
Conclusion: Dissipation Factor is irrelevant to the frequency response of a coupling capacitor in the audio band, or for that matter, even into the MHz range. It may be relevant to the dissipation/loss of a high-Q LC tank circuit of a VHF or UHF transmitter, but that's not what we're discussing here.
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I kinow about the subjective tests, and I've been using K73-16s from before that evaluation. I wouldn't easily trade them for anything else as input coupling caps at that price point, or even 10x that price point.
The only exceptions are due to space constraints, typically in compact and portable consumer equipment. A Wima MKS2XL in a 5-mm pitch bypassed with a Panasonic ECHU SMD PPS cap on the underside, is hard to beat for overall sonics and transparency within the space constraints. It's pretty close to a K73-16, just a little more closed and veiled.
I stand corrected. My theory was rather thin, to be honest.
But I'd still like to know why these polyester caps sound "less strident and aggressive at the top end" than polypropene caps.
Why not? It would help to determine whether these caps are truly "one Of The Best" or whether polyester is just an underappreciated dielectric. It could also open up for an interesting discussion about whether the construction of a cap is more important than the materials being used.
I don't really care IF these PETP caps sound good. I'm much more interested in finding out WHY they sound good. Preferably without trying to violate the laws of physics.
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Might i suggest you guys download RMAA (its free after all) and run some frequency response tests with a few different caps. My findings were the K73's roll off high end and low end, not as bad as a the K75-10's, but nowhere near as good as a quality poly cap like a Claritycap or Mundorf.
I have used a variety of Rusky caps from K42's, K72's, K75, KBG, FT3, FT1 and slowly replaced them all with quality "audio grade" caps as people call them. They are good caps for the money, but dont be fooled into thinking they are the be all and end all because they just aren't.
...all of which is my humble opinion from first hand experience.
I have used a variety of Rusky caps from K42's, K72's, K75, KBG, FT3, FT1 and slowly replaced them all with quality "audio grade" caps as people call them. They are good caps for the money, but dont be fooled into thinking they are the be all and end all because they just aren't.
...all of which is my humble opinion from first hand experience.
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