does size matter when picking caps of the same value?

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pucho812

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2 caps that are the same value, spec,  and made of the same material

both caps fit the application

caps are different physical sizes

1 is smaller in diameter but longer

1 is  bigger diameter but shorter

will there be a difference in sound? I ask because I got a buddy swearing up and down to me that the longer smaller diameter cap will sound better. I'm thinking they will sound similar of not exactly the same.
 
I looks like there is a difference in the manufacturing process between the two caps. New style, different factory, materials, etc.. There might just be a difference in the way they sound. Let your ears be the judge. Better let your friend do a blind a/b test and see if he can pick out his preferred cap.  ;)
 
If they have similar volume, using similar internal technology they will probably deliver similar performance. When in doubt look at the data sheets.

If interested you might cut them open and look for differences. I have taken many apart in the course of troubleshooting production problems, and the inside does not always match the outside.

Internal cap technology from different brands and series is different enough that trying to judge from size is about as reliable as trying to judge preamp performance by size.

Modern technology caps are often smaller, so even the bigger is better concept could lead you in the wrong direction.

JR
 
I never had the time to really spend time in testing caps. I would love to be able to do it one day, not for re-inventing the wheels but just for my own experience. However, I had this discussion with a highly regarded designer and certainly one of the people that I admire. He indicated that in his tests larger capacitors (in physical dimensions) tested electrically better most of the time. In some cases even really cheap brand caps (again electrically) tested much better than some of the expensive ones. The answer I get from this is that it is a matter of sitting down and testing both electrically and audibly to find your own.
 
Don't forget about mass.  What kind of caps film or electro?
 
who wants to put a cap in Pucho,

i'll take the guy out,

who is he Pucho?

ex mob member?
jealous husband?

singer for sublime?


1950 caps are about 1/2 the size, so keep that in mind.
in other words, don't go by size....
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go by weight! ;D :eek: ;D :eek:
 
Larger voltage is going to make the caps bigger of course
and as J.R. points out modern caps seem to be getting smaller all the time
so i'm not sure there is much of a practical choice
stock up now if you're sure you've found something you like

maybe it's a by gone thing related to electrolytics but
weren't larger voltage caps susceptable to greater leakage ?
 
pucho812

Have you done a search here?  Stuff has been posted in the past.

Have you read the PDFs from C.B.'s site? 

 
Cj don't you still owe me inductors for photos I took some 2-3 years ago?


Gus, according to what I have read physical dimensions on a cap effect the slew rate but I am wondering if that is really true or just audiophoolery?
 
The main thing that physical dimensions affect is the size... ;D

Bigger caps are potentially larger antennas in high impedance circuitry, not so much in low impedance paths.

JR
 
pucho812 said:
Cj don't you still owe me inductors for photos I took some 2-3 years ago?


Gus, according to what I have read physical dimensions on a cap effect the slew rate but I am wondering if that is really true or just audiophoolery?

I read somewhere that tall thin caps are slightly lower impedance compared to short fat caps of the same rating.  This was in reference to switch mode supplies and I can't seem to find the reference now though.  I'm not sure it matters, but if it is true that would explain why you often see a tall skinny cap laying on its side in height restricted applications.
 
Present day electrolytics are lighter and smaller than in the past.  All components are for better or worse.  They get more metals and toxins in a smaller area.  Remember that if you open them to find the magic smoke inside.  I guess you would want to measure impedance, and use the cap with the lower in an audio circuit.
It would be interesting to see shoot them with an AP in different circuits to find a difference.  Of course you would have to do 10 of each to start to get stats going.
Mike
PS:  Those monolithic BC electros still make people nervous!
 
I will say the same thing now I said a few decades ago. Parsing out differences between caps depends a lot on how used. If serious I would suggest a null circuit so you can subtract caps from each other (which only tells that they differ from each other) or from some ideal cap. One might be able to electronically synthesize a very good large cap from a variant on an active servo circuit and say a .1uF polystyrene. Then use that as the reference to compare other electrolytics.

JR



 
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