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Old 20th Jun 2021, 3:34 pm   #1
Fretking18
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Default Capacitor Guide for idiots. Help please.

Hi
I'm trying to upgrade my speaker crossovers with superior audio grade capacitors..now i have no problem at all doing the upgrades i have soldering station and am more than able to complete the required work

unfortunately i have zero electronics knowledge or specialist testing equipment i was not looking to change the values of the capacitors..as i trust the speaker manufactures put in the correct values when tuning the speakers originally.

but i do have some question in regards to upgrades..

from doing some research before hand and reading lots of articles on the internet and watching videos trying to become a bit more knowledgeable on the subject and thinking purely of capacitors in speaker crossover..it seems that polypropylene caps are the way to go and bigger *size wise" also seems to be the way to go..would i be correct in this assumption ?

my main issue is deciphering the information on the caps in order to change them for better ones
i have found several charts on the internet (attached)

is the the voltage rating on the cap particularly important in such a low voltage circuit like a crossover ?

so for instance if i found a better cap with a higher voltage than the original as long as it had the same UF rating would i be able to use it ?

even trying to cross reference my electrolytic capacitors with the chart to match values is proving a bit of a challenge

to give you some capacitor designations examples im trying to get right: the first column show the writing on the capacitors i am trying to replace and the second column is my best guess at deciphering the information by cross referencing by the charts

10mfd 63v i guessing is 10 microfarads 63 volts
15 mfd 63V = 15 Microfarads 63 volts
8mfd 50vnp = 8 microfarads 50volts
6.8 63v i dont know if the 6.8 is microfarads or not
4.7 63v i dont know if the 4.7 is microfarads or not

i really cant be sure how to actually cross reference accurately and make sure i am buying the correct replacement parts.
i'm afraid a lot of the technical jargon just goes right over my hear

my ears will be the only judge on if i have got it right or not

i apologise for the overly long post but i am finding this a little frustrating

so any help with be greatly appreciated

thanks in advance
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Old 20th Jun 2021, 4:36 pm   #2
Craig Sawyers
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Default Re: Capacitor Guide for idiots ..Help please

The voltage ratings suggest that these *might* electrolytic capacitors. Or not.

One that definitely is electrolytic is the 8mfd 50Vnp. The NP means non-polar. These are electrolytic capacitors that can take, in this case, up to 50V of either polarity. They tend to be used in loudspeaker crossovers where they have no DC bias, but have to take an audio signal. Essentially electrically they are equivalent to a pair of back to back electrolytics.

What would really help is if you could photograph the crossover and post it (Go Advanced tab just underneath). That will help us advise.

It would also help to know what speakers they are...

Craig
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Old 20th Jun 2021, 5:31 pm   #3
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Default Re: Capacitor Guide for idiots ..Help please

Let's split capacitors into electrolytic ones and all the rest.

A capacitor has two conductive metal plates facing each other with some sort of dielectric material between them. You get more capacitance if the area of the plates is bigger. You get more capacitance if the plates are closer together. Dome dielectric (insulator in other words) materials also give you more capacitance.

A microfarad is quite a large amount of capacitance, and a trick was devised to make capacitors smaller and cheaper. They used an anodised layer on the face of aluminium foil as a dielectric, and the foil as one of the electrodes. By matting the face of the foil and having a thin anodised layer, they could pack in an awful lot of microfarads into a small capacitor BUT the thin anodising made the voltage rating low. With the thin anodised layer following every detail of the matt foil, we run into a problem... the other electrode plate has to follow the finest detail of this craggy surface without any gaps. The way they did it comes as a surprise. They used an electrically conductive liquid! It's like a jelly impregnated into some permeable paper used to hold the stuff in place. A second aluminium foil with no anodising is used to connect to the liquid. Some people think the liquid is chemically active and the thing works like a battery, but they've missed the point.

Because the liquid is water-based, there is slow evaporation and loss of vapour through leaky seals. Eventually, electrolytic capacitors run out of water, dry up and stop working properly. But they're really small, and they're cheap!

Because one foil is naked aluminium, and the other has a built-up oxide (anodised) layer, they rely on there being some bias voltage. Without bias voltage, the oxide layer degrades. Worse, with reversed voltage it is driven away. As Craig says, they made 'Non polarised' electrolytics to look after this issue while handling AC signals in speakers. They work, but they aren't very good.

So, you may want to dodge these components, even though alternatives are larger and more expensive.

The other sort are just two plain, naked metal foils with a thin plastic or oiled paper film between them. Different people have different views on the various plastics, but they're nicer than electrolytics. The values you get are more accurate, and they don't have the limited lifetime set by their water content and quality of seals.

Polypropylene film capacitors should be fine. Go for the right number of microfarads. Go for the same voltage rating or a bit more, but look out for increased size.

The audio world is full of magic fairy dust and inflated prices. There are special 'audiophile' capacitors with all sorts of claims of audible improvements. If you believe in these claims, you may find yourself able to hear the improvements, especially if you paid a lot and put yourself in a position where you had to hear something to justify the cost. If you don't believe in the claims, you won't be able to hear the improvements, and you may feel you've wasted your money.

I used to design radio gear for linking aircraft into automatic anti-collision systems and air traffic control. You might suspect that I was very careful in my choice of components, and that they got the living daylights tested out of them. Hot, cold, fierce vibration, crash tests and explosive decompression, salt spray, you name it. Capacitors from good mainstream manufacturers were just fine.... and they work for audio too. So don't rush into premium priced 'audiophile' parts. Some are perfectly fine but overpriced, some are re-packaged ordinary stuff from scammers, some are just crap. Stick with a mainstream brand, and buy them from a main distributor. There are fakes of all sorts of components on the go. Nothing is so cheap that someone isn't faking it. 13 amp fuses! Jet engine parts!

David
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Old 20th Jun 2021, 5:44 pm   #4
Fretking18
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Default Re: Capacitor Guide for idiots ..Help please

thank you for your reply Craig...
the speakers im looking to upgrade are a pair of mid 80's pioneer 3 way speakers all speakers are 8 ohm
8" carboard coned woofer
3in mid range
and metal domed tweeter
i have uploaded some pictures of the crossover i'm looking to upgrade

and a pair of Castle Trent 11 2 way speakers
the 8mfd and the 4 mfd are for the Castle speakers the rest are for the pioneer
i dont have a photo at present of the castle crossover
but the 2 caps are very small
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Old 20th Jun 2021, 6:41 pm   #5
Fretking18
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Default Re: Capacitor Guide for idiots ..Help please

Quote:
Originally Posted by Radio Wrangler View Post
Let's split capacitors into electrolytic ones and all the rest.

A capacitor has two conductive metal plates facing each other with some sort of dielectric material between them. You get more capacitance if the area of the plates is bigger. You get more capacitance if the plates are closer together. Dome dielectric (insulator in other words) materials also give you more capacitance.

A microfarad is quite a large amount of capacitance, and a trick was devised to make capacitors smaller and cheaper. They used an anodised layer on the face of aluminium foil as a dielectric, and the foil as one of the electrodes. By matting the face of the foil and having a thin anodised layer, they could pack in an awful lot of microfarads into a small capacitor BUT the thin anodising made the voltage rating low. With the thin anodised layer following every detail of the matt foil, we run into a problem... the other electrode plate has to follow the finest detail of this craggy surface without any gaps. The way they did it comes as a surprise. They used an electrically conductive liquid! It's like a jelly impregnated into some permeable paper used to hold the stuff in place. A second aluminium foil with no anodising is used to connect to the liquid. Some people think the liquid is chemically active and the thing works like a battery, but they've missed the point.

Because the liquid is water-based, there is slow evaporation and loss of vapour through leaky seals. Eventually, electrolytic capacitors run out of water, dry up and stop working properly. But they're really small, and they're cheap!

Because one foil is naked aluminium, and the other has a built-up oxide (anodised) layer, they rely on there being some bias voltage. Without bias voltage, the oxide layer degrades. Worse, with reversed voltage it is driven away. As Craig says, they made 'Non polarised' electrolytics to look after this issue while handling AC signals in speakers. They work, but they aren't very good.

So, you may want to dodge these components, even though alternatives are larger and more expensive.

The other sort are just two plain, naked metal foils with a thin plastic or oiled paper film between them. Different people have different views on the various plastics, but they're nicer than electrolytics. The values you get are more accurate, and they don't have the limited lifetime set by their water content and quality of seals.

Polypropylene film capacitors should be fine. Go for the right number of microfarads. Go for the same voltage rating or a bit more, but look out for increased size.

The audio world is full of magic fairy dust and inflated prices. There are special 'audiophile' capacitors with all sorts of claims of audible improvements. If you believe in these claims, you may find yourself able to hear the improvements, especially if you paid a lot and put yourself in a position where you had to hear something to justify the cost. If you don't believe in the claims, you won't be able to hear the improvements, and you may feel you've wasted your money.

I used to design radio gear for linking aircraft into automatic anti-collision systems and air traffic control. You might suspect that I was very careful in my choice of components, and that they got the living daylights tested out of them. Hot, cold, fierce vibration, crash tests and explosive decompression, salt spray, you name it. Capacitors from good mainstream manufacturers were just fine.... and they work for audio too. So don't rush into premium priced 'audiophile' parts. Some are perfectly fine but overpriced, some are re-packaged ordinary stuff from scammers, some are just crap. Stick with a mainstream brand, and buy them from a main distributor. There are fakes of all sorts of components on the go. Nothing is so cheap that someone isn't faking it. 13 amp fuses! Jet engine parts!

David
Hi David
thank you for replying to my post..i completely understand what you are saying about the "Audiophile thing" and paying way over the odds for things because they are considered special audio quality..which gives them an expensive price tag

the electrolytic caps in the crossover are now over 30 years old..it certainly wont harm to upgrade them even if there is no increase in audio quality..i certainly don't plan on spending a fortune and waste money on snake oil

however if you shop around audio grade caps can be had for no more that three or four pounds (or less) and im more than happy to spend £30 on the pair of crossovers because improving my vintage speakers is what i enjoy doing
everything else i have done to improve them has been cheap and cheerful and has worked giving a little extra clarity and body to the sound i hear

Stuart
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Old 20th Jun 2021, 8:09 pm   #6
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Default Re: Capacitor Guide for idiots ..Help please

It's likely that those electrolytics will be past their prime, and swapping them will make you feel more confident about the future. It's remarkable how much degradation you can fail to notice, if it happens slowly enough.

If you have space, you could consider replacing the electrolytics with plastic film type and not have the worry for the future.

You probably don't have any choice with non-polarised types, but ordinary electrolytics com in different temperature grades and different life expactancy ratings... the better ones simply have better seals to slow the egress of the water content and maybe a bit more goo in them.

David
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Old 20th Jun 2021, 8:52 pm   #7
Fretking18
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Default Re: Capacitor Guide for idiots ..Help please

Quote:
Originally Posted by Radio Wrangler View Post
It's likely that those electrolytics will be past their prime, and swapping them will make you feel more confident about the future. It's remarkable how much degradation you can fail to notice, if it happens slowly enough.

If you have space, you could consider replacing the electrolytics with plastic film type and not have the worry for the future.

You probably don't have any choice with non-polarised types, but ordinary electrolytics com in different temperature grades and different life expactancy ratings... the better ones simply have better seals to slow the egress of the water content and maybe a bit more goo in them.

David
Thank you I appreciate the advice
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Old 20th Jun 2021, 9:11 pm   #8
60 oldjohn
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Default Re: Capacitor Guide for idiots ..Help please

I have only seen non polarised mentioned once, in case you missed it these are Bipolar (same meaning) it is actually wrote on them, this is very important in your application.

John.
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Old 20th Jun 2021, 10:17 pm   #9
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Default Re: Capacitor Guide for idiots ..Help please

It is very interesting to see ROE ( Rodestein Germany manufactured ) capacitors in there. They were good quality when new. What I do find interesting is the super cheap tacky hot glue mounting arrangement for the crossovers. I guess that you have no alternative to following this method due to your previous electronics knowledge statement.
I have attached a couple of pages from my supplier's catalogue for your education and guidance. The prices are in Aussie bucks and GST is the same tax as your VAT but we only pay 10%. Any of these caps will replace the electrolytics your speakers contain.

PLEASE re read the warning David gave on being conned!!!. The pages are pretty easy to follow.

Cheers and good luck, Joe.
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File Type: pdf Scr---Metalised-Polypropylene-Audio.pdf (72.6 KB, 15 views)
File Type: pdf Scr---Tin-Foil-Film-Audiophile.pdf (81.4 KB, 13 views)
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Old 21st Jun 2021, 8:58 am   #10
Fretking18
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Default Re: Capacitor Guide for idiots ..Help please

Quote:
Originally Posted by joebog1 View Post
It is very interesting to see ROE ( Rodestein Germany manufactured ) capacitors in there. They were good quality when new. What I do find interesting is the super cheap tacky hot glue mounting arrangement for the crossovers. I guess that you have no alternative to following this method due to your previous electronics knowledge statement.
I have attached a couple of pages from my supplier's catalogue for your education and guidance. The prices are in Aussie bucks and GST is the same tax as your VAT but we only pay 10%. Any of these caps will replace the electrolytics your speakers contain.

PLEASE re read the warning David gave on being conned!!!. The pages are pretty easy to follow.

Cheers and good luck, Joe.
HI Joe
thank you for replying to my post and providing the reading material
interesting to know about the quality of the caps in the crossover
i do have a multi meter so hopefully i have the correct settings to test the capacitors and if they are already good quality and are still healthy maybe i wont need to replace them
Thanks again
Stuart
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Old 21st Jun 2021, 9:00 am   #11
Fretking18
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Default Re: Capacitor Guide for idiots ..Help please

Quote:
Originally Posted by 60 oldjohn View Post
I have only seen non polarised mentioned once, in case you missed it these are Bipolar (same meaning) it is actually wrote on them, this is very important in your application.

John.
HI John
thanks for pointing the importance of that out, i will certainly bear that in mind
Regards
Stuart
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Old 21st Jun 2021, 10:11 pm   #12
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Default Re: Capacitor Guide for idiots. Help please.

The reason I posted 3 pages is to show the difference in prices as well as show the alternatives available. I have used all three types and the two types made in France are much better than Bipolar electrolytics. But look at the price difference!.

Joe
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Old 22nd Jun 2021, 7:16 pm   #13
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Default Re: Capacitor Guide for idiots. Help please.

Beware that swapping out small electrolytics for better caps such as polypropylene can change the "voicing" of the speaker in some cases due to the vastly lower ESR of the film caps.
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Old 23rd Jun 2021, 10:29 am   #14
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Default Re: Capacitor Guide for idiots. Help please.

This is an excellent resource for blowing the froth off audiophile capacitors ...
Humble Homemade Hifi - Capacitor test

There are times when copper in beeswax is called for, but there are some very good products that tick most the boxes too.
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Old 23rd Jun 2021, 10:36 am   #15
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Default Re: Capacitor Guide for idiots. Help please.

Quote:
Originally Posted by Jez1234 View Post
Beware that swapping out small electrolytics for better caps such as polypropylene can change the "voicing" of the speaker in some cases due to the vastly lower ESR of the film caps.
This, as the OP said is mid 80's Pioneer. I'd suggest that voicing is of minor concern in such a speaker.
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Old 23rd Jun 2021, 12:57 pm   #16
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Default Re: Capacitor Guide for idiots. Help please.

Quote:
Originally Posted by Craig Sawyers View Post
Quote:
Originally Posted by Jez1234 View Post
Beware that swapping out small electrolytics for better caps such as polypropylene can change the "voicing" of the speaker in some cases due to the vastly lower ESR of the film caps.
This, as the OP said is mid 80's Pioneer. I'd suggest that voicing is of minor concern in such a speaker.
In fact not worth fixing IMHO! However the point was made generically.
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Old 23rd Jun 2021, 3:22 pm   #17
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Default Re: Capacitor Guide for idiots. Help please.

The OP gets to choose his own speakers. They are his after all. Aficionados have never agreed on which are the best anyway.

I'll replace bipolar electrolytics with film capacitors any time I can find the space. Their life expectancy and lack of a wear-out mechanism being the chief attraction.

If I worried about reduced ESR (and I DO, having had fun with power regulator stability in other circuits where ceramics have started to replace electrolytics) I would consider:

1) I might not even hear a difference

2) Many speakers already have series resistors in the feeds to midrange and treble drivers to match the relative insensitivity of the bass drivers. The value can be twiddled to taste, or one added where there was none before.

3) Some speakers already have variable or switched resistors in these positions.

So, enough can be done to re-balance relative sensitivities. Resistors are cheap. And the owner may prefer any difference made.

David
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Old 24th Jun 2021, 12:18 pm   #18
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Default Re: Capacitor Guide for idiots. Help please.

Apologies.....this won't help the OP...... probably a sillly question ... but can you replace a polarised electrolytic with a bipolar or poly cap (in a crossover).

Hopefully a quick simple answer .... don't want to hijack the thread!

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Old 24th Jun 2021, 1:01 pm   #19
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Default Re: Capacitor Guide for idiots. Help please.

There shouldn't be a polarised electrolytic in a crossover... unless someone is using two in series back-to-back to create a bipolar one. If so, fitting a bipolar one is just the same thing in a single can. Fitting a plastic film capacitor ought to be fine if you have the space. They'll be significantly bigger.

David
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Old 24th Jun 2021, 2:43 pm   #20
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Default Re: Capacitor Guide for idiots. Help please.

The audio folks have a lot of folklore but there can be a grain of truth in there sometimes...

One thing to check is that some types of capacitors have a capacitance that varies with applied voltage thus making them non-linear. In many applications this doesn't matter but I see why it might in an LS cross-over network.

Of course the non-polar electrolytics will do that too because the dielectric film is slightly formed and destroyed over a cycle so you can get the effect that a "perfect" capacitor could make it sound different, not just because of different ESR.
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