I apologize for being late to this discussion, especially as @richardbrand has already made up his mind going for the DS Audio design. I have only heard good things about this optical-transformation approach and the sonic results, but have not yet had the opportunity to audition it for myself. Until two years ago I was the very happy user of the original AT-1000 (with round coils), which gave me a beautifully balanced yet propulsive musical rendering across the stylistic palette, but especially with "modern" music (Yello, !!). Just before my last trip to Japan in April 2024, I had come across a mentioning of the Miyaji MEMS phono cartridge, and followed up with some reading in a sparsely populated web space. I visited the inventor, Mr. Sawada in Hamamatsu and was invited to listen to the cartridge in his own "den" where we listened to Tsuyoshi Yamamoto and Three Blind Mice: I bought the unit right off his tonearm!
The principle behind this technology is as "revolutionary" as that of the DS Audio system, and yet - in my opinion - more "natural" in terms of the technology involved: the direct translation of air-pressure waves (i.e. "sound") into electromagnetic pulses, in the way a recording microphone operates. The stylus of this cartridge is not suspended on a fulcrum, but mechanically fixed, like vibrating vocal cords, or the lips of a brass player. The resulting air vibrations along the cantilever axis are caused by the stylus tracking through the record groves, are then acoustically amplified through two micro-"horns", and hit two micro condenser-microphones (1 sqmm ea), completely eliminating any coils, magnets, or additional mechanical devices (such as the moving mirrors in the DS system). Or in other words: there is no other mechanical translation mechanism in the entire recording-reproduction chain than microphones and cutting/tracking styli. One could go back all the way to the original phonographs, where the needle vibrations were transduced directly onto a stretched membrane on the base of an acoustic amplifier (the "horn" or "funnel"). Same principle here. There is now ample of information available, for example on my favorite AI companion Perplexity.ai: https://www.perplexity.ai/search/9d28c375-503c-42ba-a748-3f90e7d1ac27 with plenty of citations to follow up with. Only so much: because of the unique microphone-based pick-up, the resulting frequency response is COMPLETELY FLAT, and because of no coils and magnets in the signal path, RIAA re-equilibrating is no longer necessary (!!). The cartridge itself has its own (phantom)-power supply (for the micro condenser mikes) and pre-amp (the size of a pack of cigarettes) generating 25 mV (!!) output, enough for direct access to any preamp MM or AUX input w/o the need for a classical (MC) phono stage. The sonic result is simply astonishing: I have transformed my listening room into the recording venue, that's all I can say. I have never heard such a clarity and lack of any coloration, and such transparency! It reminds me of what Arthur Salvatore had to say about Ed Schilling's The Truth preamp a decade ago (which I also own, but no longer use): there seems to be nothing in between the listener and the performer. One caveat though: the frequency response of the MEMS microphones stretches well BELOW 15 HZ into the subsonic region, making the use of a subsonic filter essential for not damaging one's subs (unless the tonearm is very well dampened, which mine is not); I use the KAB "Great Sound Escort" for that purpose, and don't lose any of the skin-tickling bass on some of my favorite records. [PTP Audio turntable, ViV Rigid-Float Tonearm, Miyaji MEMS cartridge; 432 EVO Reference server, MSB Discrete DAC; Supratek Grange Preamp, Linkwitz Powerbox, Linkwitz LX-521 speakers].