Vintage Whine has previously looked at the micro-mechanics of record playback in the 9-part series, 50 Ways to Read a Record, which appeared in Copper issues #65-74 (and sorry, I’m not linking to all nine parts!). That series focused on the interfaces of arm/cartridge/record and how the record groove is traced, but didn’t really look at the mechanics of the record-spinning part of the turntable. All a turntable has to do is rotate, at a reasonably-consistent speed, right? Easy-peasey….
Unfortunately, the laws of physics have a nasty way of messing with things that, on the surface, look simple. And that is assuredly the case when it comes to spinning records.
If we go back to the beginning of cylinder and disc playback, the drive mechanism was generally some sort of clockwork contraption. A hand-turned ratcheting crank would wind up a flat, spiral spring like those used in clocks or—on a smaller scale—watches. The energy stored in the spring would gradually be released, providing motive force to the turntable platter, or the mandrel which held the cylinder.
Then as now, the means by which that motive force was transmitted to the platter or mandrel varied. Edison cylinder players used a flexible leather belt to tun the mandrel, similar to the way industrial machinery was often powered during that period. When they said “belt” in those days, it really was similar to a hold-your-pants-up belt—not a rubber band, like today’s belts. Those cylinder recorders and players were essentially lathes: the belt would rotate the mandrel holding the cylinder, while simultaneously driving a feed screw which moved the reproducer along the rotating cylinder at a theoretically-constant speed.
Here’s an odd, little-known fact: Edison initially disdained the idea of recorded cylinders as entertainment, thinking the main use of his phonograph—the term created by Edison— should be for business dictation. Cylinder recorders were made for dictation for many years after cylinders were overtaken by discs as media for music playback.
Odd, little-known fact #2: Edison was initially unable to develop a reliable clockwork motor, and early (1880s-early ’90s) cylinder recorders/players were powered by wet-cell batteries, before electric current became commonplace in homes or businesses. Those battery-powered players were hugely expensive, and were rarely found in homes: they succeeded as coin-operated music-playing devices in penny arcades.
But enough about cylinders. Berliner-style disc players—call them gramophones, or whatever—seem to have bypassed the wet-cell battery stage. Every player I’ve seen from the early years had a hand-cranked clockwork motor. Better, more expensive players utilized multiple flat, spiral-wound springs in the clockwork motor, providing a more consistent output. Speed regulation was usually by means of a flyball governor, that rotating thing you’ll see atop old-time steam engines.
A Watt’s governor—yes, named after James Watt— also known as a flyball governor. Speed is adjusted by moving the rotating ball assemblies up or down the shaft.
When we think of “modern” turntables—and by that, I mean post-WWII—there are a limited number of variations of drive mechanisms. Undoubtedly, as soon as this article is published, I’ll think of a half dozen more, or faithful readers will remind me of ones I’ve missed. So it goes.
Basically there are:
Idler drive (or idler wheel drive)
And a few oddball exceptions that I’ll mention, just because they’re interesting.
Most record players of the ’40s through the late ’60s were idler drive: the motor shaft drives against an intermediate idler wheel which in turn drives the platter. Idlers are so named because they are passive, not directly connected to a motor or power source. Think of the serpentine belt arrangement that drives the alternator and other accessories on your car; that belt is routed and kept in tension by at least one idler pulley which is not driven by the engine’s crankshaft.
Replacement 301/401 idler made by Audiosilente.
Turntable idlers traditionally have been made of a fairly hard rubber on top of a metal form and bearing, providing a bit of decoupling between the motor and platter. The idea is that the decoupling is sufficient to isolate motor noise from the platter, and thus the cartridge; in practice, idlers harden with age and become noisier as they transmit more vibration and become off-round. In most cases, the motor output shaft will be stepped; combined with the diameter of the idler, the resulting output provides speed reduction at the platter. Most turntable motors turn at 300 rpm or higher, so driving the platter directly is not an option.
Aftermarket CNC-machined replacement motor pulley for Garrard 301, made by Woodsong Audio. Selecting one of the three steps drives the idler wheel, producing 33, 45, or 78 rpm.
The most highly-regarded idler tables were originally designed for broadcast use: the Garrard 301/401 and EMT 930 are the best known, but there are dozens of others. Amongst consumer turntables, the very popular Duals were idler-driven, until they were replaced in the mid-’70s by belt-drive and direct-drive models. The Thorens TD-124 is generally thought of as idler-drive, and it is—but the drive mechanism is actually a combination of belt and idler drive, supposedly to more effectively isolate motor noise from playback. As the tables age—and most are now at least 50 years old—the complex mechanical linkage wears, and increases friction and noise.
Replacement TD-124 drive, beautifully made by Schopper. Motor at left drives stepped pulley at the right by belt, which then drives the idler wheel, held in contact with shaft by a spring-loaded arm.
The 301/401 and TD-124, along with a few other tables from Lenco and EMT, have become iconic enough to justify the reproduction of almost every part—as you see from the three pics above. The irony is that the replacement parts are generally produced by small, high-precision machine shops to a much higher standard than the original parts. Those tables were produced by the thousands, and some of the componentry was of decent but not spectacular quality. A fully-restored or modified 301 or TD-124 can easily run $10-15,000, or even more. There are also a variety of replacement bases crafted from solid hardwood, laminated sheets of plywood, Panzerholz (an extremely-dense compressed wood product), granite, and slate—as the original box-type bases tended to magnify rumble.The market is such that the revered arm/turntable maker SME purchased the rights to the name Garrard, and is either reproducing or restoring 301s. As I noted in my Munich High End report, SME’s intentions are not at all clear.
Exactly how and where the idler drives the platter varies from design to design, resulting in cliques of enthusiasts who feel one solution is superior to another. The performance characteristic cited by most fans of idler tables is a relentless rhythmic drive, particularly when compared to belt-driven tables. Most tables drive the idler against the inside of a lip on the outer edge of the platter, or against a cast or machined lip halfway between the center bearing and the outer edge. A few broadcast turntables form Gates and Gray drive the idler against the outside edge of the platter, as does the obscure consumer table from the ’50s, made in California by D&R. Fans of such “rim drive” tables cite an even stronger rhythmic sense than regular idlers. In recent years, VPI has offered a rim drive option for several turntable models.
A partly-disassembled D&R with rim drive. Idler assembly and motor were separated for shipping. From Editor Leebs’ audio-hoarder days.
VPI Avenger with rim drive. The drive-wheel is belt-driven by two motors: think of it as a cross between the TD-124 and the D&R.
What about Lencos? Often sold in the US under the Bogen brand name, Lencos are an unusual type of idler-wheel table: rather than the idler laying flat, parallel to and driving the platter, on many Lencos the idler is perpendicular to the platter and is driven by a horizontal shaft of varying diameter. Lenco enthusiasts worldwide have developed higher-quality replacement parts for the idler, the turntable top plate (lightweight, resonates), the base, and often replace the factory arms with better modern arms. The situation is like that of the 301/401 and TD-124…after you replace everything, can it be said to be authentic? Or is it a clone?
The Lenco idler, driven by a variable-diameter shaft which provides continuously-variable speed control. As shown on the website of aftermarket supplier PTP Audio.
Whether they’re unrestored or resto-modded, using a vintage turntables is analogous to driving a vintage car: it’s at least as much about the character, as it is the performance. Sure, a modern Honda Civic may well be quicker and have higher cornering limits than an Alfa Romeo GTV—but will it feel the same? I think not, so there, QED, etc., etc.
In the next issue of Copper, we’ll move on to belt-drive turntables.