I have just completed the set-up and service of a gorgeous Luxman PD-555 belt-drive turntable, one of the best high-end turntables money can buy – a true statement piece.
The Luxman PD-555 was at the top of the Luxman range of belt drive decks in the late 70s and early 80s. This turntable was a statement product in the true sense in that it had a massive platter, huge main bearing, proper heavy-duty drive motor, phase-locked loop speed stability and massive drive torque, even though the motor does not control the platter directly. I would argue that direct-drive is even better and that there are better decks out there that are direct-drive, but not too many. There are also good idler-drive decks out there like the Thorens TD-124 I am working on right now, but this is still a ripper and kills lesser decks stone dead.
For this particular job, my customer asked me to set up an almost new Ortofon RS-309D on a Luxman arm mounting plate which needed to be drilled to accept this particular arm. I was also asked to install a brand new Ortofon Cadenza Black on a brand new Ortofon LH-9000 headshell.
As you can perhaps see, this was a premium set-up of a premium deck, the kind of work I really enjoy. This combination could potentially sound very good, as the cartridge is a very good match to the higher mass of the Ortofon 12-inch tonearm. This is a critical part of setting up a turntable and one that is often overlooked because people quite often have a poor grasp of the physics involved in the mechanical interaction between the tonearm and cartridge.
Allow me to elaborate: the tonearm and cartridge operate as a unit when rigidly coupled together, as they should be. The cantilever is attached to the cartridge body via a suspension, and this suspension has a degree of “springiness” called compliance. All mechanical systems will have what’s called a resonant frequency, which is the frequency they will tend to naturally oscillate at when excited, by groove modulation for example.
OK – so basically, the needle sits in the groove and the whole needle and arm acts like a spring, with a tendency to vibrate. We want that tenancy, or resonant frequency to be OUTSIDE the audio band so that it does not colour the reproduced sound in any audible way. This leads it to falling below 20Hz for all practical purposes.
We want the resonant frequency to be between 8 and 12Hz in an ideal system. Choose a cartridge with high compliance, and you need a low-mass arm to create a COMBINATION that has a resonant frequency of between 8 and 12Hz. Choose a stiff, low-compliance cartridge, like the Cadenza Black, and you need a heavy arm, to create a combination that will have a resonant frequency in the correct 8 – 12Hz range.
This is precisely what we did here. I advised my client that he needed a stiffly sprung cartridge like the Cadenza to match the long, heavy arm, and they do indeed match very well, with the resonant frequency right where we want it. If you get this wrong, the arm will have a tendency to go into a death wobble that threatens to snap the cantilever clean off, especially where it is stiff, like say a boron rod or a jewelled cantilever. Too stiff and the whole thing will vibrate audibly at 20Hz. Too flexible and the thing will swing like crazy at 5Hz and fly off the record!
The rest of the service included cleaning and lubrication, tightening chassis fasteners, restoring the rubber vacuüm seals, adding some Australian mains plugs and a precision cartridge alignment in three axes. The deck looks a million bucks and functions perfectly. It also sounds superb!