Blown cap in speaker..

[1-3-2-4]

I'm not sure what I was thinking.. the cap that blew was 15 uF @ 100V However I just ordered 10 pcs of replacement caps that are 10 uF @ 100V

I suspect this will be a problem?

So i tried to find some radial capacitors in 15 uF but they seem pretty hard to find.

 

[ronsimpson]

10uF in parallel with 4.7uF = about 15uF.

You have 10 pcs and you only have one speaker? so:
>10uf in series with 10uf = 5uF
>then take the 5uF and parallel with a 10uF to get 15uF.
>total of 3 caps to get 15uF.

 

[Nigel Goodwin]

Except that the capacitors in a speaker need to be non-polarised, not normal electrolytics.

 

[1-3-2-4]

So can't I figure which lead is + in the circuit? Because the one's I picked up are polarized.

 

[Nigel Goodwin]

So can't I figure which lead is + in the circuit? Because the one's I picked up are polarized.

Neither lead is positive, that's the point of non-polarised capacitors.

 

[1-3-2-4]

Then we have a problem.. where can I find some where I don't have to pay $9 for one?

 

[tvtech]

Just do this. Take two 33uF 50V Electrolytic caps and solder the negatives to each other. Cut the soldered negatives off...after the soldering.

You are left with a Bipolar that will do the job. Two legs both on the Positive rail. Put it in anyway you want now, it is effectively a Bi Polar cap at a fraction of the price of a purchased one.

Works on TV's better than original Caps...should be a breeze with Audio.

For those that still want to learn....it's East West correction on Cathode Ray TV's...

Never mind. Apparently CRT are obsolete everywhere in the World except here in South Africa. So, my time on this Forum is pointless..No point in me giving advice..or helping in any way. Unless I can help with Basics and trying to help with solid grounding...

I am effectively, redundant otherwise.

Go figure and bye.

Cheers.
tvtech

 

[cr0sh]

Never mind. Apparently CRT are obsolete everywhere in the World except here in South Africa. So, my time on this Forum is pointless..No point in me giving advice..or helping in any way. Unless I can help with Basics and trying to help with solid grounding...

Just because they are "obsolete" doesn't mean there aren't a s--t-ton hanging around (many perfectly usable, too); I myself have a couple of small CRT televisions (both "portables" - one's a 13 inch, the other a 6 inch), and three CRT monitors (a CM-8 for my TRS-80 Color Computer 3, a 1084S for my Amiga, and an old Acer 14" that I keep around for occasional use on old PCs). I may not see eye-to-eye with you on all your views, but your advice and help on CRT tech will always be valuable to me and others around here, I suspect.

 

[lebevti]

Except that the capacitors in a speaker need to be non-polarised, not normal electrolytics.

how do u know? u worked on speakers before, or is there some theoretical reason that u know of that I don't?

 

[ronsimpson]

Electrolytic caps when used in power supplies will have the same voltage all day long.
Electrolytic caps when used with speakers will have the polarity reversed many times a second. This requires a different type of cap.

 

[bountyhunter]

Just because they are "obsolete" doesn't mean there aren't a s--t-ton hanging around (many perfectly usable, too);

Like the 32 inch Sony trinitron I am watching.... bought new back in 1996. Fantastic picture.

 

[bountyhunter]

how do u know? u worked on speakers before, or is there some theoretical reason that u know of that I don't?

Yes, to all questions. The voltage drive to speakers swings above and below ground or the virtual ground reference, so the voltage across the coupling caps is constantly reversing in polarity.

 

[Nigel Goodwin]

how do u know? u worked on speakers before, or is there some theoretical reason that u know of that I don't?

Both - electrolytics require a polarising voltage, there's none in a speaker.

As tvtech said, try two 33uF back to back.

 

[4pyros]

Or get non-polarized caps made for cross-overs from any audio parts supplyer.

 

[tvtech]

@ Original Poster...

Just do it. I know it works. You need 15uF @ 100V as a Cap in a speaker crossover....

Listen carefully now: buy two 33uF @ 50V normal Electrolytic caps. Nothing expensive here..no hard to find parts. And connect them as I said in my previous post. Just do it and try it. Nothing complicated here...maybe you will learn something too.

Don't dare come back here without trying above help.

tvtech

 

[bountyhunter]

Or get non-polarized caps made for cross-overs from any audio parts supplyer.

True, you can get polyester or polypropolene film caps in this voltage and capacitance range. They are higher quality than electrolytics and preferred by audiophiles for caps used in the "audio path".

 

[tvtech]

True, you can get polyester or polypropolene film caps in this voltage and capacitance range. They are higher quality than electrolytics and preferred by audiophiles for caps used in the "audio path".

They burst or catch alight. I am in an environment that sees this on a daily basis.....

Polyprop or polyester are both good, depending on manufacturer. Rubbish manufacturer...rubbish product.

Remember.....I am from South Africa. All the junk gets offloaded here.

Ah well.....till another day

tvtech

 

[Nigel Goodwin]

True, you can get polyester or polypropolene film caps in this voltage and capacitance range. They are higher quality than electrolytics and preferred by audiophiles for caps used in the "audio path".

But would be extremely large, and extremely expensive )if you could even find one) - which is why crossovers use non-polarised electrolytics.

 

[bountyhunter]

But would be extremely large, and extremely expensive )if you could even find one) - which is why crossovers use non-polarised electrolytics.

Good quality crossovers use poly caps, NP elevtrolytics are crap and have poor frequency response. Poly caps do cost more but you get what you pay for.

As for a 10uf/100V film cap:Vishay has one that is 1.75 x 0.68 inches

10.0 V-430P106X9100 V-430P106X5100 0.678" [17.22] 1.750" [44.45]

What Are the Differences in Capacitors?

There are a wide variety of capacitors available for use in crossover networks, each with their own characteristics. The 3 main types of capacitors are non-polar electrolytic, metallized polypropylene, and film and foil.

Electrolytic capacitors are the most inexpensive, and are generally used when budget is the primary concern. Electrolytic capacitors are often described as imparting a grainy or harsh sound to the input signal. If an electrolytic capacitor is to be used, usually it is best in woofer or subwoofer situations, where the large capacitor values needed make electrolytics the only economically feasible alternative. When electrolytics must be used, a second smaller capacitor of higher quality is often used in parallel to help improve overall performance. The greater the portion of the total capacitance that is made of the higher quality component, the better.

Metallized Polypropylene capacitors are the most widely used in crossovers

**broken link removed**

 

[tvtech]

Hi Bounty

The OP is probably looking at a "cheap way" to accomplish a speaker crossover repair. I know there are better more expensive options....let him learn in the meantime

Get him up to speed with the very basics first though..what say you pal

Regards,
tv tech