I have tried Duelund Cast - Copper Caps and inductors in speaker crossover networks and V-Cap Cu-TF in electronics. Big Duelund caps are hideously expensive, huge in larger values, and take forever to burn in. I had a 17 uF pair where 300 hours did nothing to change the sound so I used a cable cooker on them for a week. That did the trick. Smaller values would take less coercion. In crossover networks, when used in series, these are as good as it gets. Amazingly natural, great tonal color, dynamics, low noise and deep soundstage. In a passive XO they are equal in results to a very high-end active electronic crossover e.g. Pass Labs and save you some expense of adding the active XO and the additional amplifier - but not by a whole lot! My passive crossover for Magnepan 3.6s cost almost as much as the speakers. These work in speakers but many higher uF values are too big for electronics. The V-Cap CuTF have similar sonic characteristics to Duelunds, but I have never compared them directly. They are also expensive, will fit in electronics as coupling caps, but don't come in larger uF values. They sound much better than the VCap TFTF which are very cool sounding by comparison and a little less "present". I think both caps are really worth the price but what they're worth to you depends on the quality of your system, whatever other upgrade options you might have and your concept of price v. performance value. Go for it if you can!