Needing some small value (220pf-3000pf) caps to adjust xover points in an active tube crossover. Not having much luck finding polystyrene in the values I need (my normal choice). So, I've been led to believe non-metallized film and foil polypropylene are superior to metallized ones for audio applications. According to their datasheets, Wima FKP2 and FKP3 appear to be non-metallized, but I've also read Kemet (Evox Rifa) PFR are vastly superior to Wima FKP, and although the datasheet for Kemet PFR doesn't indicate that they are metallized (see http://www.mouser.com/ds/2/212/KEM_F3036_PFR-123965.pdf), numerous websites describe them as metallized (ie see http://www.digikey.com/catalog/en/partgroup/pfr-series/27180). So, now I'm totally confused. Which of the two would be best for my application? Or perhaps there are other (non-boutique) caps that are superior I should be considering? Opinions welcome. Thanks.
FKP and PFR are both Polypropylene Film and Foil. MKP is what's metalized. Can also be seen from their website or manufacturer's .pdf file.
Film and Foil should be better for signal coupling operations.
If they're PCB mounted where space is limited, go for the correct PCM to fit eyelets for low self inductance. However, it's for a crossover, I recommend some "boutique" film capacitors with no-inductance windings (ex. Mundorf).
http://www.wima.com/EN/selfinductance.htm
Best of luck!
Film and Foil should be better for signal coupling operations.
If they're PCB mounted where space is limited, go for the correct PCM to fit eyelets for low self inductance. However, it's for a crossover, I recommend some "boutique" film capacitors with no-inductance windings (ex. Mundorf).
http://www.wima.com/EN/selfinductance.htm
Best of luck!
Metallized is fine for line level electronics (like active crossovers) and has the advantage of compactness. Foil is best for high current applications, which yours isn't.
I've found good sound quality in the Amtrans AMCH film and foil polypropylene caps. They are available from Partsconnexion in the range of values you specified.
You can also find ERO kp1834 and kp 1838 film and foil caps as NOS on ebay at Paradise
items in Paradise of Hi-end audio components store on eBay!
I have tried these and also enjoyed the sound. Sy says that film and foil are traditionally better in high current situations and not so necessary in low current signal situations. Perhaps that is a good rule of thumb, but sometimes subtle sound advantages can be found between caps, in my humble opinion, and that is the case for the Amtrans and ERO in my experience.
Have fun with your project.
You can also find ERO kp1834 and kp 1838 film and foil caps as NOS on ebay at Paradise
items in Paradise of Hi-end audio components store on eBay!
I have tried these and also enjoyed the sound. Sy says that film and foil are traditionally better in high current situations and not so necessary in low current signal situations. Perhaps that is a good rule of thumb, but sometimes subtle sound advantages can be found between caps, in my humble opinion, and that is the case for the Amtrans and ERO in my experience.
Have fun with your project.
I have used the FKP caps as that's what was available at my local surplus store.
They do sound much better than the metallized ero caps I had in there before, were nearly the same price. They are taking a good while to settle in though.
They do sound much better than the metallized ero caps I had in there before, were nearly the same price. They are taking a good while to settle in though.
Under 1000pF you should consider C0G ceramic... don't waste your money on fancy PP caps of such small value!
you could add a zero to that, NPO over 10nF are available - some cost disadvantage but as mentioned they can be a simpler, straighter path to high objective quality than getting all the right details of "good" film, construction for your application that can be easily bought off the shelf
Slightly off topic but how do EVOX/Kemet SMR caps compare to other film types for audio applications.
http://www.kemet.com/Lists/ProductCatalog/Attachments/325/KEM_F3072_SMR.pdf
http://www.kemet.com/Lists/ProductCatalog/Attachments/325/KEM_F3072_SMR.pdf
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