Turntable Drive Systems

There is much debate as to which is the better turntable drive system. There are 3 drive systems in use today:

Belt Drive

In a belt drive system, the motor drives the platter via an elasticated belt manufactured usually from a silicone compound though sometimes using a special polymer. The belt drives either the outer edge of the platter, an inner rim on its underside, or a smaller sub platter on which the primary platter sits. Belt drive systems typically offer less torque than their direct and idler drive counterparts, and thus a good belt drive system requires that the platter have greater inertial mass to maintain speed. Systems have been developed utilising multiple belts for greater speed stability, with some systems implementing a balanced system whereby the belt drives a pair of equidistant pulleys in a triangular arrangement, equalising the load on the motor. Others still feature a pair of motors, or a flywheel to add inertial mass.

Direct Drive

Direct drive turntables utilise a motor mechanically linked to the platter or its drive system. Some such as the system employed by Technics take things a step further, incorporating a magnet on the underside of the platter which sits within the coils of the motor, effectively having the platter form part of the motor itself. Some systems utilise a motor which spins in short, controlled bursts, relying on the inertia of the platter to complete a full revolution.

Idler Drive

Idler drive turntables are far less common on today’s market, though they were once heavily used in both budget and high end machines, many of them sought after today. Much like a belt drive turntable, the platter of an idler drive turntable can be driven either via its outer edge, an inner rim on its underside or via a sub platter on which it sits. The platter is driven by a rubber idler wheel, sandwiched between its drive surface and the motor pulley.

Pros and Cons

Direct drive systems usually have the advantage where torque is concerned, and all but the most basic feature sophisticated control circuitry whereby the speed of the motor is constantly monitored and adjusted to account for stylus drag, decreasing audible speed fluctuations. . They typically require less maintenance as there are no belts to replace, and a good direct drive system produces less mechanical noise than a typical AC or DC motor.

A good direct drive system will equal or outperform any belt drive system in terms of noise, and will usually outperform their belt drive counterparts in terms of measurable speed deviation, more commonly known as wow and flutter.

It is often claimed that both direct and idler drive turntables suffer from excessive noise or rumble, which is the background noise you hear as the record plays. In a belt drive system, the belt isolates the comparatively noisy motor from the platter, preventing vibrations from entering the pickup cartridge and being heard as the record plays. In reality those making such claims are usually basing them on experience with older turntables, many of them 30+ years old, which have had little or no maintenance in their lifetime.

As with any mechanical device, a direct drive motor and the mechanics of an idler drive system will require the occasional drop of oil to keep them functioning correctly. Though many will happily spin for 30+ years with no maintenance at all, a drop or 2 of oil every few thousand hours will ensure that the turntable is performing to specification. Excessive noise is usually the result of dry lubrication in the turntable’s main bearing, an issue that will affect any turntable after years of service, regardless of the drive system it employs.

A belt drive system is usually less costly to implement, meaning that a belt drive turntable sitting at the lower end of the market will usually feature better quality components than a similarly priced direct drive model. This varies from model to model however, and cannot be used as a general guide.

In terms of usability, neither system has the edge. Some belt drive turntables require that the belt be manually moved between 2 sections of the motor pulley to alter their speed, while all direct drive systems feature electronic speed control. Many belt drive turntables do however feature electronic speed control which negates this issue.

The starting speed of a direct drive turntable is usually near instantaneous, whereas a belt drive turntable can take several seconds to get up to speed particularly if it’s using a high mass platter. This places wear on the belt, and as such it’s recommended that the turntable remain spinning when changing records. If you’d prefer to change records with the turntable stationary, a direct drive system is probably a better option.

There really is no clear winner here. There are pros and cons to all 3 systems, and providing the implementation is solid the systems are usually well matched. The quality of the main bearing and tonearm are in general of greater importance than the drive system used.

This article is part of our Guide to Turntables and Vinyl series. Continue reading: Part 12, Recommended Tools for Vinyl Fans.