Are Non-Polarized Caps (in speaker crossovers) Electrolytics?

The non-polarized (NP) caps that are used in speaker crossovers are NP, but they appear to be electrolytics. Are they actually electrolytics, and if so, how do they make them non-polarized compared to standard electrolytic caps?

Also, what is the reason they are NP, rather than use regular polarized caps?

Reply to
oldschool
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** Different manufacturing process that effectively crates two electros in series with opposite polarities.
** Polarised electros conduct when reversed by few volts, so AC current flow is different in each half cycle. Plus the caps get hot.

.... Phil

Reply to
Phil Allison

In high end speaker they are not always electolytics. They could be but the re are some different types. You can look them over at Simplyspeakers and a few other places.

Anything other that a lytic of some of those ratings will be quite expensiv e, so unless you got really good ears forget it. One technique is to put a smaller cap like a poly or something across it, but then you have to recalc ulate the value. Easy to do, just subtract what you add.

Reply to
jurb6006

Isn't it that they have a plate between the two plates ?

Reply to
jurb6006

The non electrolytics have more lifetime. In a system, retrofitting with "better caps" can result in improper repsponse from what a speaker was voiced at. Add resistance and possibly loss, and you have an electrolytic. As far as tolerance, they are pretty accurate, and often tested before installation. Normal electrolytics have given tolerances and can vary with temperature, including varying ESR.

Greg

Reply to
gregz

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** Longer than the speaker can possibly last.

** Gobbledegook.

** Plus add THD and IM.

The C value is voltage dependant, di-electric losses are large and di-electric absorption massive - none of which is true of film caps.

Non-polar electros are an economy measure fro mass market speakers.

If used in high power professional speaker, they generally explode in short order.

.... Phil

Reply to
Phil Allison

OK - some basics:

a) very nearly every speaker capacitor is non-polarized. Why? They are desi gned to work in an AC (alternating current) environment, albeit at rather l ow voltages.

b) as capacity increases, the cost of a non-electrolytic increases signific antly per uF, far more than with an electrolytic cap.

c) non-electrolytics tend to be larger than electrolytics as uF increases.

d) manufacturers, therefore, favor electrolytics as a means to lower costs and lower real-estate requirements.

Those are the most basic reasons that you will see electrolytic capacitors in speaker crossovers. "Voicing" while a very real concern will not be mate rially affected by changing out one electrolytic for another as the toleran ces are pretty sloppy as compared to non-electrolytic capacitors, and even low-end manufacturers would do some basic screening. However, if you choos e to substitute a large film cap(s) for an electrolytic, some experimentati on may be required as these days, the tolerances for film caps are commonly less than 2%. As compared to as much as +50% for electrolytics.

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This is a crossover from a Dynaco A25 speaker. Well respected speaker with excellent drivers, but from a manufacturer that pretty much did everything in the cheapest possible way. One electrolytic cap, and a bunch of sand res istors.

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This is a crossover from an AR4x speaker, contemporary to the A25, and also well respected. But from a manufacturer that did not do things in the chea pest possible way. Note the inductor, and non-electrolytic cap.

There are many ways to get there.

Peter Wieck Melrose Park, PA

Reply to
pfjw

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** AR normally built their speakers in the CHEAPEST way possible.

That white cap in you pic is clearly non original - see pic of original AR4x crossover over.

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AR normally used non-polar electros OR paper and oil caps that self destructed.

I bought a pair of AR2Ax 3-way speakers a few years ago just for the cabinets - nothing else was worth keeping.

.... Phil

.... Phil

.... Phil

Reply to
Phil Allison

signed to work in an AC (alternating current) environment, albeit at rather low voltages.

icantly per uF, far more than with an electrolytic cap.

.

s and lower real-estate requirements.

s in speaker crossovers. "Voicing" while a very real concern will not be ma terially affected by changing out one electrolytic for another as the toler ances are pretty sloppy as compared to non-electrolytic capacitors, and eve n low-end manufacturers would do some basic screening. However, if you cho ose to substitute a large film cap(s) for an electrolytic, some experimenta tion may be required as these days, the tolerances for film caps are common ly less than 2%. As compared to as much as +50% for electrolytics.

h excellent drivers, but from a manufacturer that pretty much did everythin g in the cheapest possible way. One electrolytic cap, and a bunch of sand r esistors.

They could have been cheaper by using resistance wire.

so well respected. But from a manufacturer that did not do things in the ch eapest possible way. Note the inductor, and non-electrolytic cap.

NT

Reply to
tabbypurr

AR made the 4X for very nearly Fifteen (15) years. Well over 300,000 were made.

What you are showing is a *VERY* early version from the late 60s. AR started with the Chicago-made box caps early on. For a reason so obvious, even you should be able to figure it out?

Later versions used many other different caps. What is in mine is what is very close to what is shown in my link, not Zen, however, but black, similar to a Solen with whitish ends. I purchased them in 1975, new in the box.

You keep reasoning from the specific to the general. Not only is that silly, but that is why you are so often embarrassingly wrong over incredibly simple stuff.

Peter Wieck Melrose Park, PA

Reply to
pfjw

Then the warranty calls would have been massive. Keep in mind that in those days, warranties for speakers covered shipping - and manufacturers also shipped packing if necessary.

Raw resistance wire in that application would be a recipe for disaster.

Peter Wieck Melrose Park, PA

Reply to
pfjw

What failure mode are you proposing?

NT

Reply to
tabbypurr

Pick one:

a) Overheating. b) Corrosion at the solder/crimp joints. Nichrome does not solder well. c) Mechanical damage or/due to poor connections. Those materials introduce a 'technique' issue that inevitably leads to failures. d) Excessive variability between speakers. Resistors are a manufactured ite m that can be used without much thought. Each piece of nichrome would have to be measured and cut - by someone. And then, not mixed up one-to-another as they would be difficult to label individually.

These speakers did undertake a sea voyage from Denmark to wherever, so damp salty air would be a passing thought as well.

Peter Wieck Melrose Park, PA

Reply to
pfjw

Depends what you paid for it - audiophools would go into shock at the thought of NP electrolytics in speaker crossovers.

Anything decent will have some kind of metalised film caps - and you don't necessarily have to pay audiophool prices to get it.

Reply to
Ian Field

t

Audiophools go into shock easily. Keep in mind how delicate a proposition i t must be to maintain their faith.

Many "decent" speakers have one/the-other/both inside. It is largely about real-estate and price-point as well as how critical the value might be. For critical and highly 'designed' applications, film caps are the only way to fly. For things that are less critical, an electrolytic might do just fine .

Maggie speakers are an example of where there are multiple choices. Many af ter-market 'upgrades' to their outboard crossovers use either/both, althoug h it is my impression that most factory-originals were film.

Suffice it that any speaker cap must be able to operate in an AC environmen t, meaning NP for electrolytics. No more complicated than that at the most basic level.

Peter Wieck Melrose Park, PA

Reply to
pfjw

I'm not seeing why resistances at least as large would overheat. It's only to replace 3 watters.

There's nichrome, constantan, stainless steel, manganin. FWIW. Constantan s olders well.

e a 'technique' issue that inevitably leads to failures.

It seems you have more experience than I do on this. I just know that crimp ed red hot heating elements run happily for decades before dying. And I pre sumed at much lower temps they'd be much happier.

tem that can be used without much thought. Each piece of nichrome would hav e to be measured and cut - by someone. And then, not mixed up one-to-anothe r as they would be difficult to label individually.

you think these are problems?

mp salty air would be a passing thought as well.

yes. OTOH they're inside a closed cabinet.

NT

Reply to
tabbypurr

** Few were sole here in Australia and some were made here too.

** The same type of caps were in my pair of Us made AR2Axs, totally stuffed.

** I did not do anything of the kind.

As per usual, you have deleted my entire post and forgotten what it ACTUALLY says. Usenet etiquette *requires* you to QUOTE the parts of a post you are responding to.

This avoids such errors, ambiguity and allows further responses to REFER to the exact words.

You claimed that AR did not do thing the cheapest possible way.

They did and more often than not.

I supplied a pic of ONE example of what I meant.

FYI:

Two friends of mine owned pairs of AR11s, built here under license using kits supplied from the USA, in the late 70s.

The x-overs used non-polar electros feeding the dome mids and tweeters.

Replacing these with 200V, polyester film caps made a VERY audible improvement.

You are so full of shit.

.... Phil

Reply to
Phil Allison

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** Evidence from 1978 built AR11.

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.... Phil

Reply to
Phil Allison

Sometimes you need really big values. I have measured many electrolytics that are very close to marked value, at least ones in good shape.

Some simple caps change crossover points with variable attenuator in series. So you get level and phase change at the same. Not great idea.

Reply to
gregz

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** The pic IS of a **REBUILT** AR4X crossover.

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Wot a stinking fake.

..... Phil

Reply to
Phil Allison

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