Just bought a lot of NOS (made in 1984) 5uF Siemens MKV caps with marking B25833. Siemens/Epcos contends officially that all MKV caps are made of polypropylene in oil but I found a thread that some diyaudio guys claim that the B25833 line is made of polyester in oil.
So where is the truth? I’ll try some of these babies in my tube projects and will tell you about their sonic capabilities soon but now I am looking for some manufacturing info. The second option is to disjoint a piece of them and to see the type of the film. I know how the polyester looks like but I don’t know anything about polypropylene film.
So where is the truth? I’ll try some of these babies in my tube projects and will tell you about their sonic capabilities soon but now I am looking for some manufacturing info. The second option is to disjoint a piece of them and to see the type of the film. I know how the polyester looks like but I don’t know anything about polypropylene film.
Hi reaction,
Not all MKV caps are polypropylene. For example I have B25832-C4336-K0009 in my loudspeaker and the datasheet only states plastic, not polypropylene. Also for the B25839 only plastic dielectric is specified.
According to this site
http://www.fust-electronica.nl/fustica-info1.htm
MKV is polypropyleene in oil.
I would believe the datsheet.
Of course you can dismantle the cap, romove the oil and make a infrared spectrum of the foil. That should give conclusive evidence about the dielectrum.
Not all MKV caps are polypropylene. For example I have B25832-C4336-K0009 in my loudspeaker and the datasheet only states plastic, not polypropylene. Also for the B25839 only plastic dielectric is specified.
According to this site
http://www.fust-electronica.nl/fustica-info1.htm
MKV is polypropyleene in oil.
I would believe the datsheet.
Of course you can dismantle the cap, romove the oil and make a infrared spectrum of the foil. That should give conclusive evidence about the dielectrum.
You forgot to think of the huge difference in size between polyester/polypropylene caps!
Just compare the size of your caps to the values in a datasheet of both polyester and polypropylene caps (e.g @ wima.de) with the same capacitance and voltage rating as your caps and you'll know!
Cheers
Dominique
Just compare the size of your caps to the values in a datasheet of both polyester and polypropylene caps (e.g @ wima.de) with the same capacitance and voltage rating as your caps and you'll know!
Cheers
Dominique
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