I also have the REGA ISIS VALVE cdp/DAC, so I know it’s considerable audio performance strengths as a best-of-breed cdp very well.
my take;
These 24K cds are no better performance wise than “regular” redbook silver discs on your 5-figure $$$$$ superior resolving and premium DAC cdp. It’s a waste of money providing only an elusive novelty factor for a select small cohort who follow the marketing puffery .
They won’t fulfill any performance uptick promises on your Uber high-end CD player. It’s not they are bad choices, it’s just they are no better performance-wise and thus not worth the crazy money prices ascribed to them. There was a limited edition offerings of gold disks issued 10-15 odd years ago by the major companies . They died off just like the stillborn HDCD’s . I tried them both with my old ARCAM FMJ HDCD player before buying the current high-end ISIS spinner . Both of these CD unicorns are still in my stash but are they not any excelling products.
BUT .,,quality build OEM XRCD’s can be a performance uptick …. An entirely different animal !
CAUTION: DO NOT buy ANY XRCD’s from vendors (new or used ) listed in China, and stick with properly OEM mastered Japanese listings .
All the flood of XRCD Chinese listings on EBay etc. are just rip-offs for illegal POS fakes, and sound like shite. The China offerings are NOT clones of OEM units … they are illegal and cheap crap lousy sounding fakes. I got stung once …never EVER again to be repeated .
choose wisely