Here pictured is a little capacitor that I've had great luck with for NFB caps and input filter caps.
They sound like oil caps, but they're small enough to fit on circuit boards (roughly 1/3rd larger than ecaps).
Can you tell me the brand and model? See pic.
That's not an electrolytic. The end is full of some shiny black substance. The only brand mark is a triangle. NEC? And, it sounds very, very expensive, getting every note without the goshorn of film caps. I'll be its actually an economical and overlooked product.
Matsushita? Panasonic. I've never heard a Panasonic cap like this, but the coloring is same as all of the caps in my old Technics reciever (panasonic)--except this has red lettering.
printed on the top of it.
I hope we can identify it. I'll buy a lot of them!
EDIT: I have a matching 22uf currently employed as NFB caps. . . and they do much good.