capacitor types

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Bernius1
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capacitor types

Post by Bernius1 » Wed Oct 09, 2002 5:56 am

I can't find this info in any of my textbooks.
What are the advantages(pro's/cons) between the
different tpes of capacitors? ( Mylar/Mica/
Tantalum/Ceramic/Electrolytic)
My understanding is that Tantalum is for low-
leakage, Ceramic for Hi-Freq.,and Electrolytic
is for Hi-capacitance in a small size. Any
ideas appreciated.
Can't we end all posts with a comical quip?

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Externet
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Re: capacitor types

Post by Externet » Wed Oct 09, 2002 8:05 am

Served on a silver plate... <p>Visit:<p>http://capacitors.com/pickcap/pickcap.htm<p>Enjoy,<p>Miguel
- Abolish the deciBel ! -

Bernius1
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Re: capacitor types

Post by Bernius1 » Wed Oct 09, 2002 9:51 am

Muchas Gracias, Externet !!!
Can't we end all posts with a comical quip?

Dean Huster
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Re: capacitor types

Post by Dean Huster » Thu Oct 10, 2002 5:52 am

I have the highest respect for Walt Jung, but his article tends toward some nit-picky stuff, comparing mostly different types of film capacitors. Since we're mostly hobbyists here, I think that one basic thing should be pointed out that is difficult to find in Walt's article.<p>Ceramic caps are wonderful for high frequency work and film caps are awful in that same arena. However, ceramic caps usually have one of the most awful temperature coefficients of any cap around. Never use a ceramic cap in a frequency-determining circuit or filter circuit where the frequency is critical. With a 10 degree change in temperature, you can have a horrible shift in capacitance unless you use a ceramic with an "NP0" tempco.<p>Film caps have much better tempcos so are better suited for frequency-critical circuits at audio frequencies or below a few MHz.<p>Beware of anyone who has "golden ears" and begins to describe the characteristics of a capacitor (or transformer, or tube, or amplifier) with the same kind of terms normally reserved for interior decorators, e.g., "warmth", "color", "depth", etc. Every bit of that is nothing but hogwash and snake oil.<p>Dean
Dean Huster, Electronics Curmudgeon
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Gregg
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Re: capacitor types

Post by Gregg » Thu Oct 10, 2002 8:42 am

Sorry dean, i gotta disagree with you on the discription of tubes.<p>In my opinion, as an avid guitar player and lover of old tube amps, i can hear the difference between certain tubes if comparing their warmth....etc. It does make a difference.<p>But w.r.t. caps, hogwash!!

Dean Huster
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Re: capacitor types

Post by Dean Huster » Fri Oct 11, 2002 5:52 am

Greg,<p>I agree with you, but you'll have to wade through the following to see that:<p>Vacuum tube amplfiers with their nearly-always present output transformers, do not provide the frequency response, linearity and low distortion that OTL solid state designs provide. Vacuum tube circuits, although nostalgic (and I love antique radios), do not ever reproduce program material faithfully. In fact, the cheapest solid state amp will usualy have better specifications than one of those gold-plated high-end tube amps. They add "color" of their own. If an audiophile's goal is perfect reproduction of his source material, a vacuum tube amplifier is the last thing that should be chosen for his system.<p>An audiophile can prefer a tube amp for its "warmth", "presence", "rhythm", "pacing" or "emotion" (or any of those other "golden-eared" BS or interior design terms) and that's fine. He's chosing the system for what he wants to hear. But any audiophile who claims that a tube amp reproduces more accurately than a solid state amp is living in a dream world. And as a side note, do you notice how the "golden-eared" audiophiles use home decorating terms to describe sound rather than technical terms? <p>MUSICAL INSTRUMENT AMPLIFIERS are exempt from this scathing material because they are a part of the instrument. An artist is trying to create a certain sound and the tube amps help him to do just that .... along with the fuzz boxes, reverb units, tremolo and other distortion-creating components that are added to the system. But on the other end of the industry, if you want to reproduce what that artist intended for the listener to hear, you can't insert another tube amp into the reproducing equipment without incurring added distortion. The whole idea is for the recording and reproducing systems to have zero distortion, infinite bandwidth, zero noise, etc. so that what the artist(s) produce is reproduced faithfully in the listener's ears. Speaker systems and room acoustics are the weakest links in this process anyway.<p>Dean<p>[ October 11, 2002: Message edited by: Dean Huster ]</p>
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

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L. Daniel Rosa
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Re: capacitor types

Post by L. Daniel Rosa » Fri Oct 11, 2002 11:55 am

Beyond audiophile and into audiovore... What about the wire? Don't you want to compensate for the "red" sound of copper? Especially if there is _ANY_ oxygen in it which gives it a "burnt" sound. Having the wrong strand diameter can make it "sinewy". Too exotic a speaker magnet makes it "salty". Dimensional lumber and synthetic adhesives may give the high end an "oakey", "corky", or "phenolic" whine.

bodgy
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Re: capacitor types

Post by bodgy » Fri Oct 11, 2002 4:39 pm

And your thought on the varying qualities of output transformers for valave audio?<p>colin
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russlk
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Re: capacitor types

Post by russlk » Fri Oct 11, 2002 6:56 pm

I agree with Dean: if you like the distortion of tube amps, fine. But don't say tube amps are "better" than solid state. Output transformers have a distortion all their own, particularly at high and low levels. An amplifier is better off without them.

bobsRAC
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Re: capacitor types

Post by bobsRAC » Fri Oct 11, 2002 7:02 pm

I'm from an entirely different school of though. I'm a much newer member of the electronics community than many of our valve-lovers, and therefore I am focused on modular and digital techniques.<p>The most appealing approach to me is a clean amp (having characteristics approaching ideal) and adding the warmth and tone through filters. This allows flexibility and repeatability of parameters.

Bernius1
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Re: capacitor types

Post by Bernius1 » Tue Oct 15, 2002 5:45 am

First, thank y'all for your input, both comic and
informational. I read the article (GOOD READING),
and also noticed the audio-only perspectve. Then,
reading MOUSER, I noticed that MICA caps are good
into the Ghz range. So deduction is still an
educational faculty, even if not entirely accurate. Re: tube amps, the article mentioned
correctly that many are DIRECT coupled,which helps preserve signal fidelity. Then the only
loss is in the output transformer. I'd imagine that a direct-cpld FET amp with all 'poly...'
caps would be cleanest. I be learning, no???
Can't we end all posts with a comical quip?

HomeBrew
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Re: capacitor types

Post by HomeBrew » Tue Oct 15, 2002 10:38 am

I agree with you Gregg..the tube amps have a sound quality that solid state amps can't match. Just the fact that there clean makes them sound a little harsh for many peoples taste. Even with filters it's hard to get a good mellow sound out of them. The tubes do have good sound.

bodgy
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Re: capacitor types

Post by bodgy » Tue Oct 15, 2002 3:52 pm

especially when you ping them with your finger :D <p>Or they've become leaky and you get the nice microphonic sound effects.<p>
bodgy - proud owner of a home built 95 Watt radiator that doubles as a 25 watt Amplifier.
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HomeBrew
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Re: capacitor types

Post by HomeBrew » Fri Oct 18, 2002 1:05 am

Tubes don't become leaky. The microphonic sound is caused by the tube elements becoming loose causing the effect combined with the heat from the tube. Only semiconductors become leaky.

bodgy
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Re: capacitor types

Post by bodgy » Fri Oct 18, 2002 2:38 am

Wrong term perhaps, When you get that little blue instead of red glow - I call it leaky as the vacuum is not so good - not too sure what the right term is.<p>
Still have my Radiator -playing music.<p>bodgy
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