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View Full Version : Helius: Their long awaited turntable, the Alexia, is now a reality



Neil McCauley
14-01-2016, 14:49
Helius tell us: Our long awaited turntable, the Alexia, is now a reality. Examples of the design have appeared in the industry for the last year, but now it’s now officially available to all.

Background

Though more famously known for its work in tonearms, a turntable should not be an entirely unexpected development from Helius. Although not generally remembered, Helius’ principal engineer – Geoffrey Owen – first entered the industry after engaging in contest to design a turntable to compete against the popular Linn LP12 in the late 1970’s. He subsequently went on to develop turntables for Tangent Acoustics.

Currently

Now in the second decade of the 21stC, Helius is preparing its next generation of tonearms and finds inherent limitations in the system. Essentially, we believe that optimal performance cannot be achieved until turntables are designed consider what the arm requires of it.
Rather than see the tonearm as an independent accessory to the turntable, Helius have taken a more holistic approach and reversed the concept – the turntable should be an extension of the tonearm, not the turntable being seen as the principal member of the partnership.
The reasoning is quite simple – the cartridge is the device that actually generates the music signal and is mounted in a free-moving structure we call the tonearm. Priority should really be given to helping the cartridge work as best it can.

So how is the Alexia so different?

The short answer is that tonearms are extremely sensitive to both subchassis movement and the levels of noise entering the system from the outside world. Both issues are reflected in the ultimate sound.
Alexia addresses first issue of maintaining absolute speed by fitting an optical encoder to the underside of the platter rather than the more conventional approach encoding the motor. The reasoning is simple; it’s the platter that should maintain an accurate radial speed, not the motor.

The stylus/ groove condition is perceived mechanically as a state of ever-changing friction. When the level of friction increases, the platter wants to slow down. By monitoring the platter speed 120 times per second, any speed slow-down due to louder musical passages is corrected much faster than normal.

However, maintaining pitch stability in the music is as much a function of subchassis stability.

Confounding inconvenient consequences
In the last ten years, the industry has moved away from the tradition of lightly sprung ‘floating’ subchassis in preference to suspension-less turntables. Whilst this might well have improved one aspect of the performance, it makes the system very susceptible to noise.

Alexia cures addresses this by having a suspension with only one degree of freedom – in the vertical plane. By virtue of a unique design using parallel links and tuning the movement to only 2Hz, the subchassis is (almost) impervious to environmental noise input.
Proof of its stability is easily demonstrated by bouncing the suspension – up to an inch of cyclical displacement will not be heard – the arm/cartridge remain in perfect harmony and suffer no pitch variation – nor is the stylus inclined to jump a groove.
Alive with other features, the Alexia represents a true leap forward in an industry entrenched in tradition....but then Helius has never been known to subscribe to convention.

http://www.heliusdesigns.co.uk/

Please see also http://theartofsound.net/forum/showthread.php?42502-Helius-The-Alexia-turntable-and-arm-latest-images