Pierre Lurne, founder and head designer of Audiomeca, has been designing and building analogue products for nearly 40 years. During that time he has published many papers in the technical press and applied this knowledge to a range of commercially realised turntables and arms, and more recently digital products, all released to critical acclaim. His design/manufacturing portfolio includes arms and turntables for the likes of Goldmund, Jadis and Vecteur as well as several for Audiomeca, most recently the Romance/Romeo and the awesome J1/SL5.
Now he has put that unmatched experience into the design of two very special products - the Belladonna turntable and Septum pick-up arm. Both are uniquely Lurne - no me-too or copycat designs - here Pierre Lurne has applied unique solutions to the problems involved in getting music from vinyl.
Primarily Belladonna and Septum are the ultimate expressions of Pierre Lurne's Pure Mass Concept, a fundamental engineering concept. It pervades every aspect of their design and in every case it brings huge advantages.
A body can be said to be a Pure Mass if it is perfectly balanced around a Point of Rotation, which is also the Centre of Gravity. If a force is applied to such a body, it moves in response to that force in the simplest way, not through a couple ( force x distance). It requires the same force to move a given distance in all planes of movement, not more force to move left, or up-and-down, no swinging back and forth to a preferred position like a pendulum. The body has no will of it's own, no character - it reacts perfectly to any input of energy.
The most obvious application of Pure Mass is to be seen in the design of Belladonna's platter and main bearing. Take a conventional turntable where the bearing shaft goes down to the bearing point well below the Centre of Gravity of the platter. Here the platter is balancing on that point and is continuously trying to fall over, only the bearing sleeve stopping it - it is always unstable. With a heavy platter these forces can be huge and the bearing sleeve is put under considerable pressure. This pressure translates into friction, noise and premature wear. Imagine the effect of the table being even slightly off level, then add a drive belt fitted above the bearing point, constantly trying to pull the platter over and you begin to see the problems involved. Belladonna's platter is a Pure Mass. The point of the inverted bearing and the Centre of Gravity are coincident. The drive belt pulls on a plane passing through the Centre of Gravity. If a small force is applied to the platter, (e.g. the stylus on the disc, or a badly balanced record), then the bearing sleeve only has to resist that force; the heavy platter adds nothing, as it is stable in any position. Therefore despite having a platter weighing 10 kgs, the bearing sleeve has very little to do, so it can be made out of non-resonant material with a smaller contact area, again bringing benefits of less friction and lower noise.
This Pure Mass concept has now, for the first time been extended to the entire turntable, all being balanced on a Point of Rotation at the Centre of Gravity - thus even the main body of the turntable acts as a Pure Mass.
The fact that the structure of Belladonna balances on that single point brings other benefits, not least in the field of vibration control. That single point is directly beneath, and connected to, the main bearing. This point in turn drains vibrations down into the sand-filled Ground Control base. This easy, short, single path for vibrations acts as a siphon - the vibrations simply follow the path of least resistance. No confusing multiple paths to reflect and muddle vibrations - simple and effective.
This attention to detail extends to every part of the Belladonna/Septum pairing. Take one of the major sources of vibration - the motor... Here Audiomeca has worked with ABC (previously Anagram) to produce a perfect power-supply, for both 33 1/3 and 45 rpm. This power-supply is built into the vibration-absorbing Ground Control plinth, so all power-supply vibrations are absorbed and yet it is as close to the motor as possible.
The motor itself is heavily modified with flywheels both above and below the rotor. This gives a stable store of energy for the platter, which along with the platter's high mass eliminates short-term speed changes and further reduces vibration from the motor. Turntables with separate flywheels claim to do the same thing, but in fact introduce another set of bearings to add noise.
So how does Pure Mass affect the working of the Septum? Most people are familiar with the effective mass of an arm, a measure of the arm's inertia. This is generally quoted in the vertical plane only (wrongly) and most arms have inertia that varies with the direction of movement. In essence the arm would rather move in some directions rather than others - the arm imposing its character on a signal. Likewise a pivot which is outside the Centre of Gravity will have a deleterious effect. A simple example - most unipivots have a Centre of Gravity well below their pivot. The result is that when a stylus rides a warp, the Centre of Gravity is pulled forward and lifted, it resists the movement, precisely when the stylus needs the arm to make its job easier... Then when the stylus rides down the other side the arm wants to continue to fall, then proceeds to swing back-and-forth like a pendulum. Septum doesn't do this, it rides up when the stylus wants it to, then returns without introducing a swinging element. This freedom from parasitic movement in all planes is central to the low-colouration performance of Septum.
Along with Pure Mass, the K.I.S.S. (Keep It Simple Stupid!) principle is fundamental to the design of the arm. Every joint, every bolt, every thread in an arm acts as a reflective surface to vibrations, causing colouration and reduced dynamics. In designing the Septum, Pierre Lurne has eliminated all unnecessary components. Uniquely for a unipivot, the single-piece, tapered-aluminium armtube/headshell assembly is machined from a solid, drawn bar. The unipivot removes the need for bearing races and their mass of contact points and bearing chatter. Finally, though Septum has all the usual adjustments available, such as arm-height and alignment, all the structures needed for this can be removed once optimum settings are found. No unstable VTA towers with their mass of threads and compromised rigidity, once adjusted Septum reverts to the most elegant structure possible.
This simple structure allows the cleanest path for vibrations to escape. Being machined from a drawn bar forces the crystal structure of the metal to align along the length of the armtube, the result is that vibrations from the cartridge will tend to pass along the armtube rather than bounce within. This energy escapes via the single pivot point to the high-mass, damped subchassis, or to the heavy, soft-metal counterweight, where much is absorbed rather than reflected. Simple.
Lastly, to leave this state-of-the-art turntable and pick-up arm to the vagaries of various supports, would be to miss one other area where the source can be optimised. So Belladonna has a purpose built stand, the Ground Base which is designed to protect the turntable from outside vibrations, and to offer a final sink to remaining vibrations from the turntable. Fully adjustable, and built with the same care as both Belladonna and Septum, Ground Base lifts the performance of the complete system to the highest achievable level of vinyl reproduction.
Unique, Elegant and Effective - in a world populated with heavily disguised copies of 1960's suspended turntables, and massive CNC'd monsters, Belladonna and Septum are as fresh and unique as you'd expect from the drawing board of one of the few masters of the art.
Stunning with main parts in polished black metacrylate with gold detailing Multilayer, high-mass, platter and sub-chassis designed to control Sound Propagation. No ringing material Platter weight 10kgs - inertia 2 tons Total weight 54kgs Dimension 500 x 460 x 200 mm. Easy set-up Levelling adjustable from above Designed around the Pure Mass Concept - Platter Point of Rotation on the Centre of Gravity. Platter and subchassis C of G articulated on one central spike. Maximum static and dynamic balancing. Inverted bearing Sand-filled Ground Control plinth Separate and adjustable motor block controls belt tension Flywheel enhanced motor assembly Electronically controlled motor power-supply
Stunning in polished gold and black Effective length 230 mm, effective mass 14 grms Designed around the Pure Mass Concept, pivot to stylus axis on small axis of ellipsoid of inertia. Maximum static and dynamic balancing Constant tracking force even on warped records K.I.S.S. principle throughout Lowest parts count of any high-end pick-up arm Unipivot construction Single-piece headshell and armtube, machined from drawn, solid aluminium bar. Tapered armtube for optimal stiffness and vibration control - internally damped Hard-coupled counterweight, no 'decoupling' losses Fully adjustable damping Azimuth adjustment Micrometric on-the-fly arm-height optimisation Removable arm height adjuster, anti-skating device, arm lift and arm rest Litz internal wiring, separate and shielded connection box