Motor run caps are generally lower value (less uF), but intended for continuous duty in smaller motors. MKPs work well in this application , and if it is it will say MKP right on it. Motor start are used only when starting - usually big motors like refrigeration compressors - and are disconnected when the motor comes up to speed. More uF are usually needed, and electrolytics are typically used, since they do not need to be on all the time.
Axial Capacitors
Three of ApexJr's 8uF Ultracaps at $2 each. They measure 7.5-7.7uF each. Metalized Polyprop.
Three of ApexJr's 8uF Ultracaps at $2 each. They measure 7.5-7.7uF each. Metalized Polyprop.
I can never figure why everyone is always
recommending metalized foil caps for crossover networks.
The metalized film has distortion and other issues.
We should only use quality film and foil as it is stable
and has less distortion.
There are some very real experts around here that can
explain the reason for this better than I.
recommending metalized foil caps for crossover networks.
The metalized film has distortion and other issues.
We should only use quality film and foil as it is stable
and has less distortion.
There are some very real experts around here that can
explain the reason for this better than I.
Don't get hung up about using expensive boutique items like wima. Use a Russki milspec K73-16 instead.
22uF 63V PETP Mylar Capacitor K73 16 | eBay
Your ears and your wallet will thank you.
22uF 63V PETP Mylar Capacitor K73 16 | eBay
Your ears and your wallet will thank you.
It's not the foil, or metalised that creates added distortion.
It's the dielectric that gives the added distortion, if there is AC voltage across the capacitor.
Metalised film may cause slightly higher series resistance, which might be relevant in the low impedance world of passive speaker crossover networks. However, I would expect that the difference would be smaller than sample variations of the drivers.
Lord SY is right ...unlucky 22uF is really big , you can try some russian teflon ..
anphom is a good cost 12£ or this ones is good
(CCESA-900)- 22uF 250Vdc Claritycap ESA Range polypropylene | Hifi Collective
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Have you any idea how large or expensive a 22uF teflon cap would be? That's assuming you can find somebody who actually makes them.
K73-16 are more than fit for for purpose and totally reliable. No need to spend more just for the name.
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found this, russian caps:
K31, SSG, SGM, KSO - mica, some with silver -good
K40 - PIO - very good
MBGxx, KBG-xx, OMBG - PIO
K42, MBM, BM-x - paper (w/o oil ??)
K70, K71 - Polystyren ("polystirol") - good
K72, FT - teflon ("ftoroplast") - THE BEST
K73 - Polythelene Teraphthalate film ("lavsan") - poor
K75 - combined Paper+Film (Polythelene Teraphthalate??, with or w/o oil??)
K76 - Laquer film
K78 - Polypropilen
K31, SSG, SGM, KSO - mica, some with silver -good
K40 - PIO - very good
MBGxx, KBG-xx, OMBG - PIO
K42, MBM, BM-x - paper (w/o oil ??)
K70, K71 - Polystyren ("polystirol") - good
K72, FT - teflon ("ftoroplast") - THE BEST
K73 - Polythelene Teraphthalate film ("lavsan") - poor
K75 - combined Paper+Film (Polythelene Teraphthalate??, with or w/o oil??)
K76 - Laquer film
K78 - Polypropilen
Really big for what ? (Nicola)
(22uF MKP boxed case industrial is not that large, imo)
HI mach1 ,caps can be put in parallel.... if you use scan beryllium money is last of the problems .
nice suggestion, thanks btw
nice suggestion, thanks btw
ill be the naysayer. If you have SS Berylium tweeters, they will definitely let you know wht you decide to put in front of them. To what degree do you want to investigate this phenomenon, is up to you. Cornell Dublier sells film caps through major vendors. I believe either 935 or 942c have a 20uF cap for around $20 and is an excellent value. Being sold by major suppliers may save you from being tard and feathered by the dogmatic audio intelligentsia.
You're Italian, you have to.
(Sump dump types can buy 22uF for 5-6 dollars. A matter of knowledge and Scrooge 101)
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Data?
Foils have lower ESR (may or may not be relevant for a given position in a given design), higher ripple current (greater power handling- which, again, may not be a positive if you want the crossover to fail before the driver), but no significant distortion differences.
Mouser shows the 20u PP Wimas from $6-10, depending on which series you want. There's some boutique pricing for ya. If mylar is your thing, you can indeed go cheaper.
I would never use Teflon in a speaker cap unless you want to risk capacitance modulation with signal to provide some extra distortion. Teflon is soft, windings can never be as tight and secure as PP. Great for DC duty, won't cause big issues as coupling caps in amps, but in a high vibration environment where the corner frequency is in the audible range? You can do much better.
most film caps have dV/dt specs which directly corresponds to current carrying / heating & ESR. higher current caps usually have a designator code name = pulse caps. the main difference are how the leads are connected internally to the foil or metal(ized) plates. Roederstein pioneered some the better processes for pulse caps . Wima usually does small signal high volume stuff. its in the data sheets http://www.vishay.com/landingpage/50year/roederstein.html
if they give dV/dt rating then they should be added to your list.
if they give dV/dt rating then they should be added to your list.
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