I have to tell you I do not believe in bypass caps placed on film caps. Yes, on electrolytic caps in the power supply. Usually bypassing perfectly good film caps sounds kind of phasey and odd.
Well, forget everything I just said. Why? Because these new Duelund Silver foil bypass caps are like magic. I added them to a set of .47uf Jupiter foil output caps in my Int amp and simply am overwhelmed with the improvement. My experience, in electronics, is crazy positive with these glorious sliver bypass caps. Glorious.
These would be so special as bypass caps on tweeter and midrange caps in a crossover, the output of Class D amps, coupling positions in tube gear, output on dacs....etc....
Yes, my experience has been so positive.