Saturday, January 25, 2014

Rigid arm to turntable coupling unnecessary

Another faulty part of the Linn LP12 religion is the claim that it is necessary to have a firm coupling between headshell back through the arm and the chassis up through the bearing of the turntable and the surface of the platter.  At some superficial level this may be true.  You don't want the arm and platter wandering away from one another.

But the argument as applied to making all the coupling very rigid is completely false, as that creates a connection that transmits not just position…keeping arm and platter from wandering away from one another…but vibration.  Vibration needs to be stopped from every source of vibration as close as possible from that source, and the last thing you want is vibration from the stylus traveling down the arm tube to the pivot, the chassis, the bearing, and the platter, or the vibration from the platter going the other way.

Pretty much everyone else understands this now, though some of the rigid coupling thing rears its head in the drive to eliminate non-commercial user conveniences, like removable headshells.  Imagine being able to change a cartridge without bringing your table back to the Linn dealer so he can use his special jig on the Ittok to prevent damaging the gimbals.

If you skip the rigid coupling thing, which is mostly wrong anyway (the arm must, should, and does move freely with its range of motion anyway, a slight variation in the surface of that motion is of little consequence, so long as it is not transmitted in audio band, and all the more that a pivoted arm doesn't even move in the correct surface anyway, to duplicate the cutting head, as a linear tracker at least approximates) there is little wrong even with old 1/4 cartridge headshells, which I might add were on some of the finest arms and tables (and still are!).

A standard headshell provides sufficient coupling…and it actually reduces resonances, and permits the easy addition of addition damping to the headshell…and even the cartridge body itself, where it is ultimately most useful.  It was the coupling argument which mainly lead to the disparaging of the removable headshell.  It also creates more dependency on the dealer, and saves money in arm manufacturing.

Like the arm mounting itself: damping here is a good thing.

No comments:

Post a Comment