There are three main types of

phonograph A phonograph, in its later forms also called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910) or since the 1940s called a record player, or more recently a turntable, is a device for the mechanical and analogu ...

turntable drives being manufactured today: the belt-drive,

idler-wheel {{refimprove, date=June 2015 An idler-wheel is a wheel which serves only to transmit rotation from one shaft to another, in applications where it is undesirable to connect them directly. For example, connecting a motor to the platter of a phonog ...

and

direct-drive A direct-drive mechanism is a mechanism design where the force or torque from a prime mover is transmitted directly to the effector device (such as the drive wheels of a vehicle) without involving any intermediate couplings such as a gear train or ...

systems; the names are based upon the type of coupling used between the platter of the turntable and the motor. In a belt-drive turntable the

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

is located off-center from the platter, either underneath it or entirely outside of it, and is connected to the platter or counter-platter by a

drive belt A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulley ...

made from

elastomer An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic p ...

ic material. The design of the belt-drive turntable allows the use of a less expensive motor than the

direct-drive turntable A direct-drive turntable is one of the three main phonograph designs currently being produced. The other styles are the belt-drive turntable and the idler-wheel type. Each name is based upon the type of coupling used between the platter of the ...

. Also, the elastomeric belt absorbs motor vibrations which would otherwise be picked up by the

stylus A stylus (plural styli or styluses) is a writing utensil or a small tool for some other form of marking or shaping, for example, in pottery. It can also be a computer accessory that is used to assist in navigating or providing more precision w ...

Rotational stability

Rotational stability is a key goal for turntable design that produces quality output. Many belt-drive turntables with multiple speeds have mechanical devices or rely on manual effort to move the belt between different-sized pulleys on the motor shaft. Due to difficulties in designing multiple-speed synchronous motors whose speed can be controlled electronically, such turntables frequently have DC

servomotor A servomotor (or servo motor) is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity and acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It also r ...

s. The disadvantage of DC servomotors is that they rotate in steps rather than continuously – the resulting "cogging" can add noise during playback.

Helical armature Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

motors can be used to overcome this. Problems with belt instability and deterioration in the past have largely been solved by use of modern elastic polymers. Since the 1970s, DC motors have declined in popularity; high end audiophile turntable designs use the

synchronous motor A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles. Sync ...

, which are smoother running and lower noise. Due to the existence of instabilities of mains electricity, manufacturers might try to ensure pitch stability by generating its own

sinusoidal waveform A sine wave, sinusoidal wave, or just sinusoid is a mathematical curve defined in terms of the '' sine'' trigonometric function, of which it is the graph. It is a type of continuous wave and also a smooth periodic function. It occurs often in ...

to power their AC motor. Other methods at achieving stability include using optical sensors on the platter which feed back to the electronics; or use of fly wheel assemblies. Some manufacturers use mass to deal with the problem. Heavy platters, which have higher inertia, are thus less susceptible to minute speed variations. However, mass stores energy that may be difficult to control. Heavier platter also increases wear on the bearing.

Belt-drive types

Some turntables, such as the newer versions of the

Rega Planar The Rega Planar 3, together with its successors, the P3 and RP3, is a well-known budget audiophile Phonograph, turntable by British hi-fi manufacturer, Rega Research available since 1977. It was a belt-drive deck that broke from convention, by e ...

series, use a fixed plinth with a low vibration motor and bearing attached to the same flat surface, usually constructed of wood, metal or acrylic, without suspension. Others, such as the

Linn Sondek LP12 The Linn Sondek LP12 (often shortened to Sondek or LP12) is a transcription phonograph, turntableGreenberg, Corey (1 December 1993)"Linn Sondek LP12 turntable & Klyde phono cartridge". ''Stereophile'' produced by Glasgow-based Linn Products, ma ...

, have a suspension.

Suspended-sub-chassis

The three-point "suspended sub-chassis" was a design by renowned audio pioneer

Edgar Villchur Edgar Marion Villchur (28 May 1917 – 17 October 2011) was an American inventor, educator, and writer widely known for his 1954 invention of the acoustic suspension loudspeaker which revolutionized the field of high-fidelity equipment. A sp ...

. It became the basis upon which his company created the Acoustic Research XA turntable that was launched in 1961.Gregory, Roy (23 October 2009)
"The VPI Classic Turntable"
. ''HiFi-Plus'', Issue 68 The principle behind it is that the turntable is an inert platform that allows the

to track the surface of the record accurately whilst being protected from external vibrations. The platter, sub-chassis, armboard and

tonearm A phonograph, in its later forms also called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910) or since the 1940s called a record player, or more recently a turntable, is a device for the mechanical and analogu ...

mechanically form a closed loop, and sit on top of dampers (usually three springs) which isolate the sub-assembly from its motor and its base. The motor, mounted (directly or indirectly) on the top plate, drives the turntable platter ''via'' a belt. The compression spring system of the XA was much improved upon, and popularised in the Linn Sondek LP12. A variation can be found in the

Oracle Delphi An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word ...

, where the spring is extended;Thompson, David (December 2013)
"Divine Revelation"
''Record Collector News'' another variant is the

Roksan Xerxes The Roksan Xerxes transcription turntable (often shortened to Xerxes) is a record player named after the Persian king Xerxes I and produced by London-based Roksan Audio. Designed by Roksan co-founder, Touraj Moghaddam, the Xerxes is a belt-driv ...

, whose top plate is isolated from the motor bearing assembly by compliant rubber dampers.Husband, Geoff (November 2002)
"Roksan Xerxes X turntable and Artemiz arm"
TNT Audio. Archived fro

on 11 July 2013. The main platter bearing may be upright or inverted, it is mounted on the sub-chassis along with the arm fixture. Bearings generally use an oil film to lubricate between a metal ball-bearing and the thrust-plate of the bearing's housing. More esoteric designs use an air bearing, where the spindle is supported by a high pressure flow of air.Holt, J. Gordon (December 1987

, Page 7, ''Stereophile'', Vol.10 No.8 The tonearm is usually sold separately, allowing for buyer choice and

upgrade Upgrading is the process of replacing a product with a newer version of the same product. In computing and consumer electronics an upgrade is generally a replacement of hardware, software or firmware with a newer or better version, in order to ...

Disadvantages

The main disadvantage of Belt-drive turn tables is the fact that they "ramp" to tempo; they do not instantly play the record at 33 1/3 revolutions per minute, but rather build up to this speed over the course of about one second. This creates an undesirable slurring of the record. Furthermore, over time the drive belt can wear or lose

elasticity Elasticity often refers to: *Elasticity (physics), continuum mechanics of bodies that deform reversibly under stress Elasticity may also refer to: Information technology * Elasticity (data store), the flexibility of the data model and the cl ...

, and begin to slip, causing variations in the platter speed. In addition, belt-drive turntables have much lower torque; the belt can also slip off the motor and/or platter spindle, and are thus not suitable for

turntablism Turntablism is the art of manipulating sounds and creating new music, sound effects, mixes and other creative sounds and beats, typically by using two or more turntables and a cross fader-equipped DJ mixer. The mixer is plugged into a PA system ...

. DJs who scratch or

mix Mix, mixes or mixing may refer to: Persons & places * Mix (surname) ** Tom Mix (1880-1940), American film star * nickname of Mix Diskerud (born Mikkel, 1990), Norwegian-American soccer player * Mix camp, an informal settlement in Namibia * Mix ...

generally prefer to use

References

{{Grooved track audio Thomas Edison Turntables