Thanks gonna go read it now!
Which Capacitors for Audio?
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Ricardus
WILL SOLDER FOR FOOD
The 2nd from last paragraph thanked someone for "listening tests." I'm already skeptical.
It's an interesting paper, however it fails explaining how Dissipation Factor and Dielectric Absorption correlates (or not) with distortion, except for a rather anthropomorphic blurb.
Certainly, the commonly-agreed models for both phenomenons do not have significance for analyzing distortion.
Also there is no mention of the voltage coefficient, which is probably the most important parameter in analyzing capacitor distortion.
Ricardus
WILL SOLDER FOR FOOD
The paper is from 1980. So much has changed in the last 43 years, one would hope there is a better/more recent analysis of this out there.
Cyril Bateman wrote his series of articles for Electronic World in 2002/2003, and a sequel in Linear Audio in 2015.
I'm not aware of any significant work since. It is long overdue, considering capacitor technology has changed a lot since, with much improved AL electrolytics, C0G ceramics and PPS films, and almost extinct polystyrene and polycarbonate.
AFAIK, the last Bateman paper was about DA, but did not show correlation between DA and distortion.
I'm not aware of any significant work since. It is long overdue, considering capacitor technology has changed a lot since, with much improved AL electrolytics, C0G ceramics and PPS films, and almost extinct polystyrene and polycarbonate.
AFAIK, the last Bateman paper was about DA, but did not show correlation between DA and distortion.
I don't know if so much proceedings have been gone, purchased new production of twist lock dry electrolyts and they still sound great in combination with tube amps. They nearly last forever, my tube radio is production year 1955 and still plays music. Nothing done inside, not new electrolyts. If new types will last that long, what have we won? In fact, they often last a lot less, due to bad materials or cheap production. Look at all that consumer audio from 30 years ago, they mostly need a complete recap. That is with Revox, Studer the case and many many more electronics. It's all obsolete after a decade and will be thrown in the bins, because too expensive to renovate and overhaul.
You should write the article
Indeed these RIFA capacitors were absolutely inferior, although Studer engineers thoroughly vetted them. It's called an industrial accident. Not as big as the one that put down thousands of computers, TV's, appliances, whatever... Many people do not throw their Revoxes to the bin, very often they recap them and keep them or put them for sale at a premium. Of course, apparatus with less noble lineage get thrown out.
Two things I would need:
- a good audio analyzer (AP or equivalent)
- patience
RuudNL
Well-known member
You can talk for hours about the 'sound' of capacitors.
I myself have been a professional sound engineer for about 25 years, but I have never heard a clear difference between different capacitors. (But maybe I just used 'good ones'...)
I myself have been a professional sound engineer for about 25 years, but I have never heard a clear difference between different capacitors. (But maybe I just used 'good ones'...)
You don't need to be a hen to appreciate eggs.
We are the hens that produce the eggs SE's and audiophile will taste. What do we now?
Mivel több mint 20 éve foglalkozom elektroncsöves stúdiómikrofonok (Neumann, Akg, stb.) javításával, fejlesztésével, szerintem jók. Sok paramétert kell mérni és hallgatni. A szigetelési ellenállást általában minden darabhoz megfelelő feszültségen mérem. Erre a célra egy Radiometer IM6 Megohmmeter műszert használok, csőmikrofonnal nagy zajt tud okozni. Ez a műszer 1000 teraohmig mér, a tesztfeszültség 1 voltonként 999 voltig állítható. A kapszulákat is a névleges polarizációs feszültségen kell mérni. Az SSE SX1 Interference Supressor kondenzátorokat nagyon jónak találtam (fémezett polipropilén). Igaz, hogy "dobozos" kivitelűek, de hosszú, 30-40 mm-es csatlakozókkal rendelkeznek. Még mindig sok probléma van a 100 MOhm - 1GOhm ellenállásokkal, 0805 méretű SMD ellenállásokból készítem "létra" elrendezésben, epoxi vákuum impregnálással. 47 és 10 MOhm egységektől. ("made in Japan") Sok sikert és jó egészséget ehhez a szép munkához!
I vaguely recall forum member Sam Groner doing some work quantifying nonlinearity in electrolytic capacitors.
Sam's article FWIW he had to come up with a custom measurement rig to resolve exceeding -150dB.
Edit- oops the Linear article is no longer free.
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Quadrature Bridge Measures Harmonic Distortion in Capacitors
This article considers the measurement of harmonic distortion in capacitors using a bridge circuit. Each arm of the bridge consist of one resistor and one capacitor. The bridge is driven in quadrature, such that both the differential and common-mode output voltage are nominally zero. The article introduces a procedure to construct a capacitor with very low distortion contribution, which is used in the reference arm of the bridge. The resolution of the bridge is estimated to exceed −150 dB. Measurement results for various capacitor types are presented. These show that parts with ceramic C0G dielectric have more consistent, and generally speaking also lower, distortion than Polyester, Polypropylene or Polystyrene film capacitors.Linear Audio, Volume 12, September 2016
This article is co-authored by Scott Wurcer.
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JR
"The RIFA's are a must and the X2 across the AC line (or just snip it out). You can replace the gold Frako electrolytics on the PS and transport boards and leave the audio cards for later if you'd like. Frakos do tend to fail dead short so keep that in mind."
Thats what they build some decades ago, when transistor gear took over the regime and tube electronics had to leave the place for improvement.
All those "improvements", shouldn't they lead to audio nirvana and shouldn't we have reached it now? If we failed, why is that? Because every new generation beats the old audio gear, we should be in heaven with our audio systems. The opposite is often the case. What went wrong and when it began to take the wrong direction?
Four decades ago, I asked that question, constantly swapping new gear in and out of the system and burning thousands or Reichsmark.
It has something to do with the sound of every single part in electronics and with a perfect matched system thats not easily achivable without knowledge.
I changed caps and listened to their different sounds, resistors and everything. One has to do to evaluate which part makes which sound.
Caps have a big influence on the sound and electrolytics a big influence on the lifetime of audio gear. I don't expect my gear to fail within my lifetime.
And I'm sure my heirs even will have fun with it for a very long time.
All that can be achieved, if one studies how different longlife pro audio has and is been build comparing to consumer gear.
You get what you pay for, but the best is always not achievable for the masses. And often the price tag doesn't say much about quality.
Only persons who know how the best was designed and build for a lifetime show interest for internal values. All others are blinded by fancy front plates and massive aluminum housings. It has nothing to do with internal qualities and long, trouble free lifetime.
Always search to become an expert on the field of interest or try to consult independent experts. But for most, this is much too time- consuming and to consult an expert, which gives independent advise is a no go in audio forums. Nobody will pay me even five cents for giving advise on such topics.
So they still burn their hard working money and still swap gear in and out constantly. Exactly the same what I've done some four decades ago.
And the industry still keeps advertising with the same slogans: "New and improved beats the old in the dust".
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That's right, I had forgotten about this article.
Out of the best contenders, Polystyrene is almost extinct, C0G limited in value (<33nF), only Polypropylene remains.
PPS was not even considered at the time.
Moving target.
I still have piles of polystyrene caps in my back lab. I used lots of them for my kit business. They are not robust enough for modern manufacturing processes. Maybe someone will make bigger cog/npo caps, but not soon enough to do me any good.
JR
JR
You can get some assemblies which are a bunch of SMT caps stacked up together in a little frame that holds them together and has bigger SMT feet to mount the entire assembly. Pretty expensive for what they are.
I have in certain situations. Clearly in some equalizer circuits. In the T filter EQ I built there was a clear difference between Wima PP and other PP caps. I’ve never heard a difference in coupling caps. I wouldn’t say they are never audible or always audible.
One thing to be careful about in uncontrolled listening tests is that the value of the capacitors being compared are closely matched.
JR
The value of the caps tested were selected within 0.1% of each other. I bought 100 pcs of each type and selected. I wasn’t screwing around with this console build.
Edit: Band gain and bandwidth was on rotary switches so also very well matched.
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