Ceramic VS. Metal Film Capacitors

[mr.adambeck]

does it matter whether or not I use a metal film cap vs a ceramic one?  I am missing one cap component in a fuzz I'm building, and I the Radioshack near me had the right size cap, but it's a ceramic one, which I've never used in anything.

Thanks

[anchovie]

Some people's ears might say that ceramic sounds worse than film, yours may not notice the difference. When I've built stuff with ceramic caps, if it's sounded good enough then I don't worry about whether I should swap the caps later.

[Taylor]

It will work. Some people think it will sound different. Here's R.G. talking about different caps.

The hifi guys are more nuts on this subject, but I'll give you in a capsule the more-or-less accepted rules of thumb. I do hate to see the hifi tweako mystique infiltrating the musical and effects arena... sigh...
For tonal qualities, caps are largely chosen by their dielectric absorption.
The semi-accepted order is:
teflon - thought to sound ultimately clear, use for circuit boards too
polystyrene - ditto
polycarbonate - ditto minus a hair
polypropylene - ditto, plus available in uF sizes
polyester (mylar) - Ok if you can't get something better, not a lot worse than the
other plastic films, and much better than those lower in the list
NPO ceramic - only available in tiny sizes
aluminum electrolytic - the accepted standard for uF and
up sizes simply on $ and size
paper - obsolete, can't get them anymore
thought to be "tweedy" or some such
other ceramic types - thought to sound "grainy"
tantalum - unreliable and thought to sound
grainy
Above teflon is vacuum then air, which are impractical for all normal circuits. There exist other exotica, like glass dielectric capacitors for special purposes.
There are capacitance size and voltage limits, obviously. 100uF polystyrene caps don't exist, while aluminum is barely working up a sweat at 100uF. Likewise, there are no 1000V aluminums, but 1Kv ceramics are easy and cheap. Also the construction of the capacitor, whether stacked, rolled, folded, extended tab, etc., etc., can have real effects (as distinguished from silliness like cryogenic stress relief or water jacketing).
I personally have staged a couple of capacitor shootouts, and haven't yet found someone who could tell simply by listening whether they were hearing music through a polypropylene versus ceramic, although I don't doubt that someone might be able to.
"Best sounding in FX" is not something you can nail down, as you will find that each person may perceive "better" and "best" as meaning something different. I'd be willing to make a significant bet with you that I could set up a test where I changed only the capacitor and you would not be able to do more than 50% +/- 2% correct telling the caps apart by sound alone.
IMHO you would be wasting your money chasing down and buying super premium caps for effects. Use mylar and aluminum, get it working, and when it's going good, substitute out for some super-premium stuff until you satisfy your curiosity. On the other hand, don't just use the high-value ceramic caps for audio coupling (even though many highly sought after vintage effects did exactly this).

There are people who disagree with me strenuously, even violently.

As mentioned at the end, many of the famous "mojo"-ful vintage effects used ceramics. I use ceramics all the time.

[tiges_ tendres]

I actually like ceramic a lot.

They are cheap, I am cheap

It's a winning combination!

[Gus]

I posted a very good link for cap tests in another thread.  The person did distortion tests on caps.  Not all ceramics are the same. 

[Taylor]

Thanks for that, but posting that you posted a link somewhere else is considerably less helpful than actually posting a link... 

Edit: dug around your posts, found the thread:

http://www.diystompboxes.com/smfforum/index.php?topic=75896.msg619073#msg619073

And the link:

http://uk.geocities.com/cyrilb2@btinternet.com/downloads_4.html

[WLS]

Another issue is the life span. Ceramic caps have a shorter life span then the metal film capacitors.


Bill

[Taylor]

Shorter by how much? And when they go bad, do they go open, or does the value just drift gradually?

[aron]

I wouldn't worry about it too much, but as a rule of thumb, I use film for everything that I can get easily. Ceramic for the rest (usually small values).

[bluesdevil]

I never thought I would say this, but I liked the sound of ceramics (.1uf's) in the Harmonic Perculator. Poly caps sounded fuller, but dull. One of the ceramic caps (between stages) was actually microphonic, but the poly cap when in the same position was not... weird? For a fuzz I would definitely give the ceramics a try.

[Wales]

Sorry to be new, but are all the polly caps and the teflon on R.G. list film?

[Mugshot]

this whole cap thing just blows my mind! i built two fuzzes (FF, silicon), every component was similar except for the output cap (0.01uF) - the first one used boxed metal film, the other a ceramic disc i popped off a junk cassette player. there was a very BIG difference - FF1 (boxed metal film cap) was boomy, plenty of bass; FF2 (with ceramic cap taken from junk radio) was way clearer, less bass, way better in my opinion, that between the two, FF2 will cut more in a live band situation.

i had spare ceramic caps taken from the same junk radio so i instinctively desoldered the metal film cap from FF1. so FF1 and FF2 now sounds very very similar.

now for the interesting part.

last Wednesday (Friday today here), i bought new ceramic caps (103 - 0.01uF) and replaced the old ceramic cap installed on FF1. holy cow! what happened? apparently the bass content came back (well not as much as when i used metal film cap). same cap type, same value, but different sound?

why? could it be because of age? the junk radio has been unused for about 10 years already, and found it in our stack of old junk.

[Projectile]

this whole cap thing just blows my mind! i built two fuzzes (FF, silicon), every component was similar except for the output cap (0.01uF) - the first one used boxed metal film, the other a ceramic disc i popped off a junk cassette player. there was a very BIG difference - FF1 (boxed metal film cap) was boomy, plenty of bass; FF2 (with ceramic cap taken from junk radio) was way clearer, less bass, way better in my opinion, that between the two, FF2 will cut more in a live band situation.

i had spare ceramic caps taken from the same junk radio so i instinctively desoldered the metal film cap from FF1. so FF1 and FF2 now sounds very very similar.

now for the interesting part.

last Wednesday (Friday today here), i bought new ceramic caps (103 - 0.01uF) and replaced the old ceramic cap installed on FF1. holy cow! what happened? apparently the bass content came back (well not as much as when i used metal film cap). same cap type, same value, but different sound?

why? could it be because of age? the junk radio has been unused for about 10 years already, and found it in our stack of old junk.

Did you measure the actual value of the caps? My guess is the difference had a lot more to do with the tolerance and age of the caps than the composition. Even 10% is a very audible difference in terms of filter frequencies. If you like less bass in the circuit then you could always try using a smaller value cap.

[Gus]

Taylor   That is cool you found the link
http://uk.geocities.com/cyrilb2@btinternet.com/

People read the pdfs, pay attention to voltage difference "across" the cap and distortion, pay attention to different ceramic type caps and how some distort and some hardly distort at all. Pay attention to  cap construction issues.

Other stuff to google, dielectric stress, Jung, Marsh caps, Companies that build cap web site sometimes have interesting papers, microphonics.

http://greygum.net/sbench/sbench102/caps.html   

[WLS]

When building something for myself I will spend the extra money for Orange Drops Caps when using film. I like the sound that they give off. But I feel their is a difference in caps and the sound that different composits produce. I guess that it is up to the individual as to what is right for the application that it is being used in. If your going after a true sound of a ventage box then to mimic the manufacture is probably the best bet.


Bill

[Mugshot]

Did you measure the actual value of the caps?

My guess is the difference had a lot more to do with the tolerance and age of the caps than the composition. Even 10% is a very audible difference in terms of filter frequencies. If you like less bass in the circuit then you could always try using a smaller value cap.

nope, didnt measure  but since the label was the same (103), i assumed the old ceramic cap would sound similar to a new one of the same value. prolly tolerance, idk. but never thought tolerance could make that much difference.

last night i desoldered the new ceramic cap on FF1 (history: metal film, old ceramic, new ceramic) and installed a new mylar cap(?), the green one. among the four caps i auditioned this one sounded best, not too boomy, bass content is just right, clear and defined harmonics. just like the old ceramic, but clearer and more articulate!

weird still, because the FF with mylar cap sounded way different from the boxed metal film cap i used previously although both have similar tolerances (denoted by the J in the label). what gives?

[markv]

i find ceramics to sound 'glass like' but sometimes a little too metallic sounding when used too much especially on a dirt pedal.