has anyone else tried Lloyd Walkers latest tweak

Dear Rodman, The crystal in those old radios is an RF generator, not an RF absorber. In the old days, I think those radios were "tuned" to a particular frequency by changing the crystal, each one of which resonated at a different frequency. In fact, every time I tried to do a search on crystals as an absorber of RF, I got a list of papers documenting the fact that an electrically energized crystal (not an inert crystal glued to a tonearm) will radiate RFI.

Also, if what you theorize were true, we wouldn't be having this discussion; it would be common knowledge.

Benjie, if we have parallel universes, what would they be like?

Lew & Al (Rodman), regarding the function of crystals in early radio equipment, you're both right, but you are referring to two different applications. And to some extent to two different eras.

Crystals were (and still are, in some applications) used to control the resonant frequency of tuned circuits, such as RF oscillators. While in the earliest days of radio, and later in radio hobby kits, they were used as detectors/demodulators, where (as Rodman indicated) their rectification properties were used to extract the audio information carried on AM (amplitude-modulated) radio signals.

Regards,
-- Al

Rodman, I agree with your point wrt the passive nature of Shakti however there is a significant difference between the Shakti Stone and a single crystal or even group of crystals we see in some audio applications. That difference is that for Shakti Stone there is a circuit that the quartz crystal is part of, whereas in the case of the black diamond crystal, assuming for the moment it actually IS a crystal (symmetrical atomic structure), there is no circuit.

Here's the brief description from Shakti web site:

"Through a unique application of quartz oscillators, a broad spectrum of RFI is attenuated. Being a piezeo-electric material, quartz is capable of converting an electric field into mechanical energy. In situations where quartz is employed in active components, the desired goal is to accentuate one resonant frequency to the exclusion of all others. However, within this stage of SHAKTI, quartz is used in a manner to produce the broadest sampling of frequencies to better absorb the somewhat unpredictable EMI. One of the reasons quartz has never been used in this type of circuit is because, as effective as it is as a converter of electrical energy, its very high Q means that most of the conversion to mechanical energy swiftly changes back to electrical. To overcome this problem, careful experimentation produced the necessary resistive element that is incorporated to substantially lower the Q. The result is effective dissipation within the first 1/2 cycle. This stage provides absorption/dissipation benefits for both external and self -generated sources of RFI."