Cartridge/phono stage package £5995
Nineteen-forty-eight was a big year for fans of Analogue. The long-playing (LP) record that we know and love was launched that year, as were the first moving-magnet and moving-coil cartridge designs required to play it. To this day, the two cartridge types still dominate, to the extent that it would be easy to think that there was no other way of doing that specific job other than by having a small magnet move relative to a coil, or vice-versa.
DS Audio would beg to differ. The company isn’t the first to design an optical-type cartridge. There were examples from the likes of Toshiba, Kenwood, Trio and Sharp decades ago, but these failed to catch on for reasons technical (excessive heat from the internal bulbs) and commercial (by the late ’70s, the big manufacturers had started to divert resources towards new technology such as CD). But the idea of an optical cartridge retained much promise.
UNCONVENTIONAL DESIGN
The advent of LEDs is fundamental for DS Audio’s cartridges to work. In the DS 003, there are two small infrared LED lamps, one for each channel, and a matching pair of light detection photocells. While the DS 003 has a pretty conventional aluminium cantilever (and line-contact stylus tip), rather than the cantilever being attached to a magnet (or coil) as it would in a conventional cartridge, here it has a ‘shading plate’ instead. This plate is positioned between the LEDs and the photocells. As the stylus traces the bumps in the record groove, this shading plate moves in sympathy and the photocells detect any change in brightness from the light received from the partnering LED. That change in light brightness represents the music signal.
The advantages of such a design are obvious. The mass of the ‘shading plate’, now made of Beryllium rather than the aluminium of the previous-generation model, is much lower than a typical coil or magnet, so the stylus tip can track the bumps in the record groove with more agility and accuracy. Also, there are no unwanted internal magnetic effects generated, as there would be in conventional set-ups. The result should be better sound.
There are complications though. Heat is no longer a hurdle, as LEDs produce so much less than the bulbs used in those early designs. But, the cartridge still needs power for those LEDs and, of course, the electrical output from those photocells is very different from that delivered by a conventional cartridge in terms of the relationship between stylus-tip movement and
