Turntables, Arms & Cartridges

While the Grand Master shares the same LED/photocell concept as all DS Audio's proprietary pick-ups, the core internals of this flagship are both further miniaturised and separated into a dual-mono construction. The white LED at the front of the pick-up is purely decorative. Inside, however, not one but two narrow-beam infra-red (850µm) LEDs are positioned between the stylus tip and cantilever fulcrum, their output deflected by an extremely fine beryllium plate that's fixed to the rear of the diamond cantilever. The plate modulates the IR light falling onto two photodiodes, each generating an electrical current that directly mirrors either the left or right channel signal. Moreover, as the moving mass of the stylus/cantilever/plate has been reduced in this model, the Grand Master's high frequency sensitivity (its response) is further extended just as the dual-mono LED/photocells have reduced any residual crosstalk.

But what of the equaliser? A traditional RIAA phono preamp is designed to accommodate the velocity-sensitive output of standard MM/MCs where the signal voltage increases with groove excursion and, thus, increasing signal frequency. By contrast, DS Audio's photoelectric conversion is sensitive only to the amplitude of the movement of the stylus and requires only a relatively subtle HF boost to realise a 'flat' response with all RIAA pre-eq'd LPs. Incidentally, the ~70mV output of the photocells is carried by the L+/R+ cartridge pins while the 12V DC input to the IR LEDs (and white LED) enters via the L–/R– pins. PM