Yes, and they do work. Most noticeably is atop the input transformers of my tube amps, above/below a Genesis Digital Lens and above the DAC power supply xfmr. Where they make little or no difference is on (my) speakers, power conditioner, pre-amp power supply, pre-amp and ML 20.6 monos. However, apart from the tube amps, I get the same results without the stones by separating the digital front end from the pre-amp by at least 6 feet.
