Has anyone tried the Deulund-Mundorf Ultra Speaker Purifiers?

I have and am really glad I did!

Attached to my speaker binding posts (to the treble ones-or to the single pair if that is what you have). It definitely takes 100+ hours for the Deulund cap to open up. But I did notice right away that they mitigate HF noise. Now after a partial breakin period, the imaging has snapped into focus like never before. And the soundstage has become wider and deeper. This is a change that has greatly improved my overall listening experience. For $345, a no brainer. The changes are obvious and wonderful.

As I understand it, these purifiers clean up HF 12K Hz and above. That is above the tweeter crossover point and there is no negative effect or interference with the speaker crossover. I guess it is kind of like getting a much higher quality tweeter. In any event, now having much clearer and cleaner high treble has a large effect on the presentation.