OK...i have now received my 2 Finite Elemente Resonators (used...20 cents on the dollar). If you own a Zanden DAC, they are definitely worth using on the Power Supply Unit (which gets very hot, so was concerned about using HRS damping plate). In comparing the Resonator to the HRS damping plate on the main DAC unit, i would say i prefer the HRS damping plate. it is just that much better, when i tap the component w/ and w/out...the resonance/metallic vibration is even more of a solid 'thud' rather than a ring with the hRS...though frankly both are excellent. you could be fooled into thinking thin sheet metal is quarter-inch thick aluminum...if you tap anywhere, it is a solid thud, rather than a 'ting'...no idea how they do that with one resonator that manages to do that across the entire casing...home-made devices definitely do not do this. And of course, soundwise, both are excellent...HRS wins by a nose. with HRS, There is even that much cleaner a signal.
But since the Zanden Power Tube Supply gets superhot, i prefer the Resonator since it is metal (as compared with the HRS softer rubberized material...which is probably meant to withstand heat...but you never know.)
I took the second resonator and used it on my CJ preamp, the Nordost Qx4...i moved it around to various spots on each. Yes, there is a difference but oh so slight...i'd be upset if i'd paid full retail, when i could have bought Ceraballs, or HRS damping feet, kept it for CDs, towards an IC upgrade, etc.
The main reason that it works so extremely well on Zanden but not on the rest, is that Zanden casings are very thin metal...i feel like they ring at extreme high treble (choral soprano, flute, etc), or at least that the treble seems to "bleed"/shimmer. That shimmer is dramatically reduced now, pretty much gone, so as opposed to a shimmering note, i can focus on a word being sung, or a high note being played. Nice...particularly at the price.