Ceramic vs. Polystyrene Capacitor Distortion Analysis
- Thread starter Mark (Basspig) Weiss
- Start date
I am not sure why capacitor "phase change" couldn't be measured... Capacitor (L, and R) self-resonance is well-known and easy to characterize. As is ESR and so forth... The problem for most 'philes is lack of access to the equipment to take measurements and lack of knowledge and experience to interpret the measurements. At least IME.
Ceramic capacitors are used mostly in high-power RF applications. The material is prone to traps and various mechanical issues that have made it a non-player is most other applications these days. Most film capacitors will not exhibit significant distortion or noise within their operating range (frequency, voltage, temperature).
Ceramic capacitors are used mostly in high-power RF applications. The material is prone to traps and various mechanical issues that have made it a non-player is most other applications these days. Most film capacitors will not exhibit significant distortion or noise within their operating range (frequency, voltage, temperature).
Don,
Are you able to interpret the measurements of different types of film capacitors in terms of sound quality?
Dunno, show me some measurements. However, IME nobody can defeat a mind already made up. My experience with measurements and audiophiles has been very interesting. Most of the time the 'philes were annoyed when they could hear things we couldn't measure, especially when they could not pass any sort of blind listening test. However, there were those cases when repeatability happened and we had to figure out what and how to measure to explain what was clearly heard. Again IME to dismiss measurements or hearing out of hand is a mistake, but I am a skeptic.
In the past I was able to correlate fairly gross (to my standards) measured characteristics of a few different types of capacitors to listening tests. This was in the 1980's. We took ceramic, electrolytic, mica, polystyrene (not sure those are available now), polypropelyne, and teflon capacitors of equal values and used them in the coupling circuit of a Hafler preamp (because it was a kit build of mine so easy to fiddle with). We compared THD, IMD, and noise plus did pulse testing to look for hysteresis as well as the usual VNA measurements, then conducted listening tests. I am not sure anything we did was new or the results any different than any other experiment, but it was fun at the time.
We played a little with speaker caps but it was hard to get repeatable results in DBTs.
In the past I was able to correlate fairly gross (to my standards) measured characteristics of a few different types of capacitors to listening tests. This was in the 1980's. We took ceramic, electrolytic, mica, polystyrene (not sure those are available now), polypropelyne, and teflon capacitors of equal values and used them in the coupling circuit of a Hafler preamp (because it was a kit build of mine so easy to fiddle with). We compared THD, IMD, and noise plus did pulse testing to look for hysteresis as well as the usual VNA measurements, then conducted listening tests. I am not sure anything we did was new or the results any different than any other experiment, but it was fun at the time.
We played a little with speaker caps but it was hard to get repeatable results in DBTs.
Gary: I've used Rels over the years and would say they're are good for the money. I prefer, everything being equal, the "sound" of Teflons though I will eventually get around to listening to some Duelands.
What I really wanted to ask is does REL still make polystyrenes? As I understood it, there were some new rules and regs about PS and PS caps were a thing of the past. That's why some like cj moved onto the Teflons while others are using polypropylene, etc.
Interesting. I can imagine you could easily separate the ceramic, electrolytic and mica using measurements, but was there any measurable difference in the audio band between the polystyrene, polypropelyne and teflon capacitors?
And it wasn't that long ago that people thought that cap quality only counted for those units in the signal path. Now take a look at any top flight product. You'll find high quality caps used in both the circuit path and power supply! You will also see some manufacturers (I think ARC does this but not positive), where they use a "blend" of caps from different manufacturers in their design.
As far as I know, other than a few studies showing that some capacitors (such as tantalum, electrolytic or ceramic capacitors) introduce measurable distortion, you will find no objective and independent studies on the effects of capacitor types in sound quality - illusions (in the audiophile sense of the word) are not simple to prove by scientific methods.
My personal view - there is not such thing as the sound of a component, but there is the sound of component in a defined position of a defined circuit. In other words, there is so single magic, only group magic.
Good caps will not make a silk purse out of sow's ear circuit design. OTOH, crappy caps in a good circuit will hold back its potential. The best? Great caps and solid circuit design.
garylkoh
WBF Technical Expert (Speakers & Audio Equipment)
Myles: check out Rel's website http://www.reliablecapacitors.com/
To let the cat out of the bag, I use polystyrene caps in many of my crossovers. I do like the "sound" of teflon, but find the break-in characteristics so different from both polystyrene and polypropylene that you have to use all teflon in the crossover, and then it becomes "too much".
I think so but I honestly don't remember... It seems like we could pick out one, but the other two were essentially identical. IIRC, the polystyrene had the greatest bandwidth, but of course any of them had fo well over the audio range. I do remember as a group the poly's and teflon measured much better than the ceramic or electrolytic; seems like the mica was between the groups.
Looks like this became a hot topic overnight.
My test was intended to be basic and not too formal. I simply chose some caps I had handy in the shop. The ceramic caps are Y5F material. Some older guitar amps and early hi-fi amps (tube-based) used ceramic disc caps in the tone control circuits! Oh, the horrors...!
I'm editing a video of a similar test setup. I conducted a test this evening with ceramic and polyester film capacitors of larger capacitance and I used low frequencies to generate the test conditions. I just have to finish the narration and render the video, which I'll do later today.
My test was intended to be basic and not too formal. I simply chose some caps I had handy in the shop. The ceramic caps are Y5F material. Some older guitar amps and early hi-fi amps (tube-based) used ceramic disc caps in the tone control circuits! Oh, the horrors...!
I'm editing a video of a similar test setup. I conducted a test this evening with ceramic and polyester film capacitors of larger capacitance and I used low frequencies to generate the test conditions. I just have to finish the narration and render the video, which I'll do later today.
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