SLATEDECK TURNTABLE PLINTHS
Upgrading any idler drive turntable has just been made easier. Using Slatedeck's unique Welsh Slate plinths you can bring the performance of your cherished Garrard, Lenco or Thorens turntable to the quality for which these designs were originally renowned . In this article we show you why classic idler drive turntables are considered the peak of vinyl replay performance and how to realise their best sound quality. |
The Slatedeck Principle |
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Today we understand this technique in a way that the designers only hinted at. Sophisticated measurement techniques that have led to other 'improvements' in hi-fi component performance over the decades can now be used to ascertain exactly how these classic turntables perform on different mounting boards. A brief perusal of information on these turntables on the 'net will yield a variety of recommmendations for mounting, and all are based around using thick, massive supports many of which utilise some form or other of Constrained Layer Damping (CLD) to achieve the desired sonic performance. However all is not as it might seem. Damping vibration, whether in loudspeakers or turntables, has often been seen as the ultimate way of 'curing' unwanted resonance. What is becoming clear in modern designs, however, is that a system can be 'overdamped' resulting in a lifeless, boring portrayal of the music on the disc. In fact it turns out that applying loads of damping material to any vibrating object is not necessarily the best method of controlling vibration. In response to the 'idler drive rumble' effects noticed in the '60s a variety of after-market damping 'solutions' appeared. Chief amongst these was 'Black Knight Rumblecure', a product, or more exactly series of additional damping methods, that the turntable owner could apply to all parts of the 'offending' chassis, platter and plinth (including the option of a thick, rubbery, mat which sat atop the platter). These products reduced some of the audible effects of rumble but never eliminated them as they did not attack the source of the problem. We can now see that the answer lies in the using a mounting material which is inherently solid, massy and naturally critically damped. Overdamping, by interspersing layers of, say, plywood with 'lossy' layers of rubber will not act as good a vibration conductor as a solid material. The reason is that the damping layers actually resist conduction leaving only the top layer of plywood that is in contact with the chassis to do the job required. Accordingly users report better results from a mounting board of, say, 38mm thick mahogany than by using some of the CLD plinth methods.
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