The Absolute Sound’s Technology & Innovation Awards 2025 feature in a special Fall issue of the US magazine, celebrating “the greatest technologies and innovators in high-end audio”. Prominent among them is Tetsuaki Ayoagi, founder and chief designer of DS Audio and pioneer of the modern optical phono cartridge.

“While we’ve grown used to regular game-changing advancements in digital audio, analog is a different story,” writes reviewer Jonathan Valin. “So, the advent of something truly new is something to write home about, which is what I’m doing here.”

Optical cartridges use conventional diamond styli to read a record’s groove – there’s nothing digital about them. Where they differ from conventional magnetic designs is the way in which they translate those tiny stylus movements into electrical signals. The movements are translated into variations in the intensity of light from LEDs in the cartridge body, the brightness of which is modulated by shading plates mounted on the cantilever. Each tiny movement of the stylus moves the shading plates, altering the strength of the LEDs’ beams. The modulating beams are read by high-precision photoelectric sensors within the cartridge, which convert them into varying voltages. The voltages are then equalized by DS Audio’s bespoke EQ units before travelling on through the usual amplification pathways.

“Here’s a revolution that deserves celebration – a new thing that does the old thing better,” enthuses Valin. “Eliminating magnets and coils appears to have many audible advantages… It is my contention that, with LPs, the only verifiable reference isn’t a supposed “absolute sound” but the actual mastertape the recording was pressed from… Comparing the sonics of a first-gen dub of a mastertape to that of the LP of the same performance gives me a very clear idea of how much cartridges, tonearms, turntables and phono preamps (not to mention cables, amps, preamps and speakers) are changing the sound of the source. Given this bias, the advent of [DS Audio’s]  optical cartridges has been a godsend… they come closer to the rich, smooth, airy, three-dimensional sound of the source (ie. the mastertape) than any moving coil or magnet I’ve heard.”

“In the hidebound world of high-end audio it’s not often that something new (or greatly improved) becomes a runaway success, but DS Audio’s optical cartridges have done that very thing.”

Innovator of the Year Award 2025: DS Audio’s Tetsuaki (‘Aki’) Aoyagi

“Calling the optical cartridge ‘new’ isn’t actually correct,” notes Valin, since the idea of using light rather than magnets dates back to the 1920s – though it took another 20 years for Philco to introduce a functional version, and until the 1970s for Toshiba to reintroduce the concept with its C-100P model. Both, however, were prone to failure due to the heat generated by bulbs within the design, which would also need factory replacement when they burned out.

In 2013, a fully functional model was finally launched by DS Audio, using advances in LED and photoelectric sensor technology, as used in the computer mouse. Aki had been an engineer with Digital Stream Corporation which, alongside Microsoft, co-developed the optical mouse – based on which he “had the happy idea of adapting these devices in a new phono cartridge.”

“In a short ten-year span, Aki has changed the paradigm in phono cartridges,” writes Valin.

Furthermore, not only has Aki continued to advance the technology and his models to their current ‘third generation’ level, he has also been relentless in his pursuit of trickle-down technology, bringing the benefits of the company’s optical innovations to an increasingly more accessible range of models and price points. Plus, in a particularly rare move, he has even published his design technology to enable other companies to enter the market!

“For this achievement – and the many others that have accompanied it – Tetsuaki Aoyagi earns a well-deserved TAS Innovator of the Year Award. Indeed, IMO Aki is the Innovator of the Decade,” says Valin. 

Technology of the Year Award 2025: DS Audio Grand Master EX

A Technology of the Year Award goes to DS Audio’s top-of-range model, the Grand Master EX (for ‘Extreme’) optical phono cartridge.

“DS Audio has produced the highest fidelity optical cartridge I’ve heard, coming far closer to the sound of mastertapes than any cartridge [of any kind] I’ve heard,” writes Valin.

“The addition of a single-piece diamond stylus/cantilever is the clear reason for the EX’s sonic superiority,” he notes.

“Listening to other cartridges is like watching a hi-res movie. Listening to the DS Audio Grand Master EX is like going to a play… The Grand Master EX is that kind of breakthrough.”

Discover the full range of DS Audio optical cartridges and accessories at ds-audio.biz/en/ and locate your nearest specialist retailer via UK distributor www.soundfowndations.co.uk

Check out The Absolute Sound’s special Fall Technology & Innovation Awards 2025 issue for more innovators and innovations in high-end audio.