MKP-1837 Metalized Polypropylene
Tony Gee of www:HumbleHomemadehifi.com says:
Technical Specifications: Metalized polypropylene, radial capacitor, designed for LC/RC filter circuits, coupling and de-coupling at high frequencies.
Sound: I was tipped by Klaus Witte of Germany to try this capacitor as a bypass cap for the Mundorf M-CAP SUPREME. I tried them as a bypass for the tweeter series caps in my Progress speaker and I must say I am very impressed! To get straight to the point they don't change a Supreme into a Supreme Silver-Oil but they really do clear things up. I must admit I was skeptical at first as the value is only 10nF (0,01uF) - and the caps in the Progress are 12,6uF. The difference is most noticeable with classical music but also good quality recordings of jazz and fusion benefit: No change in sound stage width or depth but there is more "concert hall acoustics" that let you get into the recording more. Not as liquid as silver/oil but they take away the "grainy" edge from the Supreme's. A gain in clarity and transparency making instruments better separable from each other, the violins in an orchestra are a group of individual violins instead of one mass. Jazz drum brushes sound more like a brush than a "shush".
Verdict: Can’t live without them! – Use them as bypass cap with any capacitor, they cost practically nothing!"
pcX matches Capacitors for $1.00 per pair