Duelund Capacitors??

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.

The copper foil is well worth the extra cost, the Duelund's are exceptional components, the resistors being a no brainer best buy for sure.

The caps may seem a little costly but once you compare them to others and understand the type of Machinery and time necessary to make these, they are well worth every dollar.

I have the Duelund caps installed in the tweeter high pass xovers of my speakers. I did not do lots of analysis or comparison, but Tony Gee has done an enormous amount. Look at his web page, humblehomemadehifi.com under the 'cap test' heading. He ultimately preferred the copper VSFs over dozens of others he's tested.

One other thing to note, and this is directly from Tony - to get the 'sound' of a capacitor, you only need 10-20% of the total value to be the 'good' cap. Example - you need a 5 uF cap for a HPF. Use a 4.5 uF Clarity Cap and a 0.5 uF VSF copper, and it's almost identical to the sound of a 5 uF VSF, and you've spent significantly less.

Happy listening.