DS-Audio
Optical cartridges &
equalizers

The game changer

The principle of tradional cartridges (MM and MC) is based on electromagnetic induction of coils in a magnetic field. The unique optical cartridge by DS Audio on the other hand, is based on the detection of vibrations of the stylus by means of a ray of light. The low moving mass and the absence of magnetic induction-forces create a very high signal to noise ratio, low distortion and exceptional dynamics. The system exhibits a very clean and simple signal path without much gain and hum and extensive RIAA correction.  Sonically, the advantages are: no coloration, very low noise floor, extremely good retrieval of micro-details and an incredibly dynamic sound.

Traditionally, there are two types of phono cartridges, MM and MC. These cartridges do have their limitations. To start with MM: this cartridge has a moving magnet (which is quite heavy) and fixed coils surroundig the magnet. Typical output voltage is just 3 mV, a large amplification and correction is needed to bring the signal to line level, which undoubtedly will introduce noise and also hum. In MC elements, the coils move and the magnets are stationary. The problem here is the even smaller output voltage (typically 160 µV) which, in turn, calls for a step-up transformer or other ways to gain even more than needed for an MM cartridge, introducing even more problems. Now, enter the world of optical cartridges. These have very low moving mass, no magnetic forces that restrict freedom of movement from the needle, and on top of that, they produce quite a hefty 50mV output signal, this eliminates the need for large gains.

The only company producing optical cartridges is DS-Audio, based in Sagamihara City, Japan. In the past, manufacturers like Toshiba tried to create optical elements without much success: at that time, high-efficiency LEDs were not available, so incandescent bulbs had to be used, this led to all kinds of thermal problems in the long run.

Traditional MM/MCs are velocity-sensitive devices whose voltage output increases with groove excursion and increasing signal frequency. By contrast, DS Audio’s photo-electric conversion is sensitive only to the amplitude of the movement of the stylus. Nevertheless, while this system has the potential to offer a lower moving mass – stylus/ cantilever/optical plate – than the stylus/cantilever/magnet or coils of a MM/MC design, it still requires a proprietary phono stage to power-up the LED and correctly compensate for the LP’s RIAA replay characteristic. You will soon notice, plops and ticks are a lot less with your new DS Audio cartridge. This has all to do with the different frequency compensation used. While normal RIAA preamps have quite a large amplification in the lower frequencies, the dedicated DS Audio preamp actually attenuates(!) the signal, resulting in less audible unwanted plops and ticks.

The DS-E1 has the same optical-mechanical system and wire-suspended cantilever as the DS Master 1 and other models, allowing more than 24 dB in channel separation, with an output exceeding 500 mV. Built to meet the lower price, the new cartridge features an aluminium cantilever and elliptical stylus. The accompanying and matching DS-E1 equaliser/phono stage uses an operational amplifier at the heart of its amplification circuit to cut down on the number of components required. This unit is more compact and lightweight being about a third the size of the original DS-002 equaliser.

DS-E1 Cartridge:

• Optical, so not MM or MC
• Aluminium body
• Aluminium cantilever
• Elliptical stylus
• Stylus replacement service available
• Needle pressure: 1.6-1.8 g (1.7 g recommended)
• Signal output Photo-electric conversion
• Output signal level > 50 mV
• Channel separation > 24 dB (@ 1 kHz)
• Weight 8.1 g

DS-E1 Equalizer:

• Dedicated for DS-Audio optical cartridges
• RCA Inputs from tone arm
• Rated output voltage 500 mV (@ 1 kHz)
• Impedance 120 Ω
• Preamplifier input impedance > 10 kΩ
• Weight 1.4 kg
• Dimensions 20x7x16 cm

Reviews:
DS Audio DS-E1 Cartridge & Equalizer by Ken Kessler @ hifinews.com
DS Audio E1 Optical Cartridge, an Audio Waypoint by Ken Redmond @ theaudiobeatnik.com
DS Audio DS-E1 Optical Phono Cartridge / Phono Energizer and DS Audio ION 001 Vinyl Ionizer Review. New heavyweight contenders by Maurice Jeffries @ enjoythemusic.com