Question about capacitor
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Question about capacitor
Hey everyone, I had a question.
I'm recapping some of my input modules on my console, and ran across a a few caps that don't seem to have a positive or negative.
Most all of them have the negative side labeled, and the spot on the PCB where they go looks like this -) |-
However, these other ones, although they look just like all the radial caps on the module, don't have a negative side labeled. They have similar ratings, such as 25V 47uf or 16v 100uF or whatever, but once again, dont' appear to have a positive or negative side. They mount the same way as the others (two leads coming from the same side, wrapped in a black casing)
Could these be "non polarized capacitors"?
Anyone know what these things are called so I can order the proper ones?
Thanks in advance,
I'm recapping some of my input modules on my console, and ran across a a few caps that don't seem to have a positive or negative.
Most all of them have the negative side labeled, and the spot on the PCB where they go looks like this -) |-
However, these other ones, although they look just like all the radial caps on the module, don't have a negative side labeled. They have similar ratings, such as 25V 47uf or 16v 100uF or whatever, but once again, dont' appear to have a positive or negative side. They mount the same way as the others (two leads coming from the same side, wrapped in a black casing)
Could these be "non polarized capacitors"?
Anyone know what these things are called so I can order the proper ones?
Thanks in advance,
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They could be, but it's more likely that the -ve is just labelled in some other fashion.
I imagine they do make radial non-polarized electrolytics, but all the ones I've seen have been axial, for use in crossovers and the like.
The schematic, hopefully also has a comprehensive parts list?
Do you have any pictures of them? Worth a 1000 words and all that
I imagine they do make radial non-polarized electrolytics, but all the ones I've seen have been axial, for use in crossovers and the like.
The schematic, hopefully also has a comprehensive parts list?
Do you have any pictures of them? Worth a 1000 words and all that
The previous statement is from a guy who records his own, and other projects for fun. No money is made.
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Re: Question about capacitor
Well he did say
So figure those values are likely electrolytics.southsider wrote:However, these other ones, although they look just like all the radial caps on the module, don't have a negative side labeled. They have similar ratings, such as 25V 47uf or 16v 100uF or whatever, but once again, dont' appear to have a positive or negative side. They mount the same way as the others (two leads coming from the same side, wrapped in a black casing),
The previous statement is from a guy who records his own, and other projects for fun. No money is made.
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Re: Question about capacitor
Good point.Drone wrote:Well he did say
So figure those values are likely electrolytics.southsider wrote:However, these other ones, although they look just like all the radial caps on the module, don't have a negative side labeled. They have similar ratings, such as 25V 47uf or 16v 100uF or whatever, but once again, dont' appear to have a positive or negative side. They mount the same way as the others (two leads coming from the same side, wrapped in a black casing),
A photograph would be remarkably useful.
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Bipolar EL caps will not have the black stripe down one side with a - sign on it. Otherwise, the markings for them can be anything.
Best to use a DVM and check the DC offsets facing each cap first, most manufacturers don't do that so many cases the cap is wired in the wrong way and doesn't get the proper bias for a low THD reproduction.
Use high quality, low impedance caps like Panasonic FR series, enlarge the values to extend the low end and reduce phase shift. Wire in the + lead towards the positive DC offset, - towards the negative DC offset.
Bipoar caps are really two polarized caps connected internally, double the losses. If you find DC offsets below about 5 mv, usually you can remove that cap and use a wire in it's place. The best cap I ever heard was a piece of wire.
Best to use a DVM and check the DC offsets facing each cap first, most manufacturers don't do that so many cases the cap is wired in the wrong way and doesn't get the proper bias for a low THD reproduction.
Use high quality, low impedance caps like Panasonic FR series, enlarge the values to extend the low end and reduce phase shift. Wire in the + lead towards the positive DC offset, - towards the negative DC offset.
Bipoar caps are really two polarized caps connected internally, double the losses. If you find DC offsets below about 5 mv, usually you can remove that cap and use a wire in it's place. The best cap I ever heard was a piece of wire.
Jim Williams
Audio Upgrades
Audio Upgrades
Schematics help immensely, but measuring voltage will probably answer the question too.Jim Williams wrote:Bipoar caps are really two polarized caps connected internally, double the losses. If you find DC offsets below about 5 mv, usually you can remove that cap and use a wire in it's place. The best cap I ever heard was a piece of wire.
I personally can't imagine a reason for a cap that large except as a bypass for a power supply node somewhere along the line. Straight wire there would usually cause malfunction if not destruction. Course, you would be seeing a significant voltage at that point...
It's worth mentioning that you can make your own bipolar cap from two appropriately sized polars exactly by connecting the negative legs together. Probably won't fit in the original hole unless maybe you use axial caps.
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No, I agree. I just can't think of any place that a cap that big would do any good AND need to be bipolar. Course, it's all speculation for us out here without a schematic...Jim Williams wrote:I've never seen a bipolar el cap used for psu decoupling, they are polarized with a black stripe showing polarity. Knowing what you are doing is first before anything else.
Don't let the smoke out.
Bipolar caps show lower distortion than polarized electrolytics (Douglas Self, among others, has written about this) of the same size. The phantom blocking cap on a mic preamp will often be 47uF or bigger; the voltage would be higher, though.
Bipolar caps are easy to source (from digikey, mouser, or wherever) and not terribly expensive. It's probably there for a reason...
"NP" is another relatively common marking on those.
Bipolar caps are easy to source (from digikey, mouser, or wherever) and not terribly expensive. It's probably there for a reason...
"NP" is another relatively common marking on those.
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