And why the two-part review? Because, when it comes to the Blackbird, the structure itself and the way it’s put together is so unusual that it takes a little while to get your head around. It’s best understood by breaking it down, operationally and mechanically, into its thinking and execution. Throw that into the mix with the listening and you risk a severe case of mission creep, which does neither the product nor the reader any favours. So part one of this review will concentrate on the way this arm is put together and from what – and how those aspects contribute to its remarkable custom options. The sound I’ll get to once the constructional dust has settled.
Supatrac describe the Blackbird’s operating principle as a “sideways uni-pivot” – which is an audio oxy-moron if ever there was one. However, it does go someway towards describing the arm’s unique bearing arrangement. To me, as I’ve already suggested, it’s more of a cross between the string bearing of the WTT and Kuzma’s 4Point, so perhaps I’d better explain…
However, in order to understand the bearing it’s best to start with the arm-wand itself. The arm’s moving element consists of a box-section arm-tube and an open frame box that sits underneath the counterweight end. This box takes the form of a truncated and perforated pyramidal section, fabricated in mild steel, narrow at the top, wide at the bottom, with vertical faces fore and aft. This structure is absolutely key to the arm’s operation and elegance: It’s key to its adaptability and it’s key to its customisable nature. I’ll get to its actual construction later, but for the moment, just understanding the shape is all-important as is the fact that, unlike aluminium, it isn’t non-magnetic.
The Well Tempered arm hung its moving part (the arm-wand) from a pair of filaments, angled out and down from a high-mounted central beam to create a broad based triangle. In that arm, the bottom of both filaments was attached to a circular ‘paddle’ that was entirely immersed in a bath of silicon fluid, to create a stationary reference for the pivot. The Blackbird takes the triangulated filaments from the WT design, with their frictionless vertical pivot (or hinge) and – thankfully – dispenses with the vat of silicon fluid, a substance that apparently defies gravity and all other constraints when it comes to spreading across any and every available surface. Instead, the Blackbird pulls the filaments VERY slightly to the rear, creating a forward moment that pulls the vertical front face of the arm-wand’s counterweight box against a horizontally positioned conical point – the sideways uni-pivot. That pivot point allows the arm freedom of movement, laterally and vertically, while the filaments support its weight: The mass of the arm-wand presses against the horizontal contact (helped by a small magnet on the other end of the pivot) a force that resists but is also augmented by the drag of the stylus in the groove. The arm arrives with a choice of two different pivot magnets and a spare for each.
