Duelund Capacitors??

Hello the difference of the 2 is much with Copper the detail is more fleshed out and harmonics a little richer , the Silver may be even a little better,for sure the Copper is the best value for a expensive cap and the most natural
on the planet .Some may like the pio paper in oil that is a little more rich perhaps a bit to much .the Copper VSF is the way to go, and for sure their carbon resistors for they are the best I have ever used just clear and open.
P.s "The caps are 200v", Not as a few others stated 100.

Agreed. Based on our experience with Jensen aluminum vs. Jensen copper (Jensen is the OEM for Duelund), copper foil is the way to go.

We have, in fact used the Duelund VSF copper foil and can highly recommend it. If you're on a budget, forget the Duelund aluminum and just use the regular Mundorf MCap Supreme (not the silver/gold/oil versions), which is almost as good as the VSF in copper.

Are you using them in crossovers or as couling capacitors in amps?

The Duelund VSF Copper is currently used as part of a loudspeaker x-over. It's the only cap that's directly in the signal path, making it very easy to evaluate.

The Jensens were tried in several circuits, including as coupling caps in a tubed phono preamp, output caps in a tubed active line stage, and as a driver tube's cathode to ground bypass in a 300B SET amplifier. I can't remember if we ever tried them in the x-over.

The Jensen aluminums made the components almost unlistenable. By contrast, the copper Jensens were reasonably smooth and pleasant. In the electronics, we ultimately preferred the VCap TFTF Teflon.

Based on that experience, we didn't bother with the Duelund aluminum and went straight for the copper.