Twelve-inch tonearms have traditionally been a part of hi-fi's far left field. Perhaps that's why there's no way you can refer to them as '30cm arms', as metric never reached the UK vinyl fraternity.

In the past, you would have had to scour the furthest reaches of the audio galaxy to find a turntable designed to accept one, but not any more. SME has been making twelve-inch arms for some time, because they have a cult following in the Far East, and now it has developed a puprose-built deck to go with these longer arm designs.

The long arms have a theoretical advantage over their nine-inch (22.5cm) counterparts, because tracking error is reduced. This is because of the shallower arc that the cartridge follows as it crosses the vinyl. The reason why you don't see many twelve-inchers is that there is a trade-off: the longer an arm is the more likely it is to resonate at a frequency that will affect the stylus.

And the fact you need a turntable plinth the size of Hampshire to house the thing. With its massive, die-cast magnesium beam, the SME Series 300 Model 312S is designed to give you the benefits of the breed without its shortcomings. Except for size.

Which is where the deck comes into play. The name of the turntable launched to partner this arm, the SME Model 20/12, suggests accurately that it is a version of the SME Model 20 that's been extended to cater for a twelve-inch arm. However, the extra wide newcomer bears very little resemblance to its namesake.

Almost any other company in hi-fi and beyond would have given this turntable another name for clarity's sake as much as that of marketing, but SME does things differently. It builds its components to a standard that Rolls Royce should emulate and it pays more attention to detail than the finest watch makers. Then it arrives at a retail price that takes not the slightest notice of marketing norms. It's enough to make you proud to be British.

Weighty proposition

If anything, it actually looks more like a widened SME Model 30. With a 6.5kg platter sitting on a 19mm spindle and an all-up weight of 33.5kg, it comes pretty close to SME's range topper in many respects. In truth, it is a completely new turntable that shares very few parts with either range-mate. The two slabs of machined aluminium that make up its chassis are considerably thicker than the Model 20 (but not as thick as the Model 30) and the suspension towers in each corner fall somewhere between the two designs, too.

Those suspension towers support the top plate on 40 rubber 'O' rings, with high-frequency movement resisted by fluid damping in a central reservoir around the bearing housing (you can see it if you look between the top and bottom plates). The large platter is, at 324mm in diameter, wider than a vinyl LP and has greater inertia as a result. It also makes it a little more difficult to remove a record and discourages non-clamped record changes without stopping the platter.

But the sonic benefits of using the clamp make it worth using for all but casual listening - that and the fact that you get to handle a lovely piece of metalwork with a fast acting coarse thread that's a joy to use.