The Grand Prix Audio Monaco Turntable

Asking Questions? Giving Answers!

Given the inherent accuracy and low noise levels of the table, it’s no surprise that GPA were unwilling to compromise concentric accuracy with a peripheral clamp, or risk the noise and variability associated with vacuum clamping. Instead they’ve opted for a simple screwdown clamp, but use it in conjunction with a soft washer that is placed beneath the disc and compressed by it, thus damping the record. The washers come in three different durometers (or hardnesses) to optimally damp different weight records, another example of the meticulous engineering that’s been applied throughout this record player. The end result is a near textbook speed performance from a critically damped platter system whose drive is contained within the lateral dimensions of the platter itself.

The second part of the motor-unit equation is the plinth system, a structure that must deal with the practical questions of accommodating and levelling the platter and arm, as well as dealing with internal and external sources of vibration. The compact nature of the drive system itself means that the plinth needs to be no bigger than the platter, while GPA’s experience with composite structures and mechanical resonance means that the actual shape and construction of the plinth offer a previously impossible range of options. They have chosen to create a double skin structure, it’s complex shape moulded in carbon-fibre and accurately integrating all the hard-points necessary for mounting the external elements and drive. This includes a six-bolt fixing for the alloy outrigger arm-board, located near the deck’s centre of gravity. The precision machined alloy plate that supports the arm simply slides in horizontally before fixing, allowing the ‘table to support tonearms of any length or type, pivoted or parallel tracking, although only one at a time. Alloy? Yes, alloy. Real engineering is about the appropriate use of materials rather than profligate expenditure. The specially selected aluminium serves its purpose perfectly, so why bother with a complex and more costly composite solution of dubious merit?

The void between the two outer skins is filled with a polymer damping compound creating an incredibly rigid, dimensionally accurate, stable and inert structure, representing the second layer in the ‘table’s defence against both internal and external mechanical resonance. Second? Yes. The first is the oil-bath which is an effective damper for resonance generated within the dynamic elements of the bearing itself. Bolting the bearing sleeve, well and stationary parts of the motor directly to the plinth creates an effective sink for residual energy, which will otherwise simply circulate within the structure.

GPA have eschewed any form of external suspension, instead preferring to rely on users investing in a proper support, an area of course in which the company cut its audio teeth.

Instead the plinth is supported on three conical alloy feet, each tipped with a large diameter ceramic ball, the ball and socket arrangement allowing the feet to pivot, ensuring a firm footing. One of the feet is fixed in height and this is located immediately beneath the tonearm outrigger to avoid introducing an unwanted element of flexibility or source of vibration at this critical point. The others support the opposite side of the plinth, their balls seated in very finely threaded sockets that allow for precise height adjustment. The underside of each foot is finished off with a thin layer of Sorbothane, again selected to match the weight distribution and mass of the deck. Set up consists of installing the plinth and platter on the feet, levelling the whole and filling the bearing oil bath through ports provided in the label area of the platter with the syringe provided, then sealing them with self-adhesive labels. As well as the syringe you also get a machinist’s level, a beautifully executed spanner to fit the levelling sockets, a holder on which to store the compression washers for the platter, and a superbly machined plate to support your tonearm’s external termination box (should it have one).

Control is provided by the small external micro-processor unit and this provides on/off, 33 and 45, with a 10-second lag between switch on and full speed at 33. There’s also fine pitch control in 0.2% steps, with an illuminated scale showing the current setting. The control unit is fed from a small DC transformer and connected to the ‘table via a locking Lemo connector. Once assembled the deck’s diminutive proportions will come as something of a shock to audiophiles brought up on the “bigger is better” school of turntable design, although the all-up weight of 18kg and the lightweight platter gives you a fair indication of just how inert the plinth element really is.

I installed the Monaco turntable in two locations, atop the heavy-duty top shelf mounted on my finite elemente HD-03 rack and also on GPA’s own superbly engineered Perspex and carbon-fibre Brooklands wall-shelf, a unit that shares materials and the critically-damped approach of the deck. The deck proved remarkably impervious to differences in support, and subtly greater transparency and focus from the wall shelf could simply reflect its solid mounting compared to the floor standing rack. Either way, the deck performed superbly. Tonearm used was a current Triplanar VIIi, with a range of different cartridges. As previously described, setting the deck up is an object lesson in engineering exactitude with both the tools and the measure available to ensure perfect results easily achieved. Moving it short distances is similarly simple; just make sure that you keep it level to prevent spillage from the oil bath (and having a second pair of hands available to place the feet is a real bonus).