Ortofon: An introduction to cartridge theory and manufacturing

The process of making a pick-up cartridge for DJ usage is not a linear one. It essentially involves the combination of four different components. They are…

Body/Shell
Stylus Body
Generator System
Connections

Ortofon, a small manufacturing company based out of Nakskov, Denmark, are quite unique as a company, in that their product portfolio is still primarily focussed on cartridge manufacture; and moreover that the majority of their construction is done in house with custom equipment. Ortofon's employees are masters of micro-technologies, and due to the miniscule nature of cartridge technology, all cartridges are constructed by hand by a small and dedicated team of employees. It is for these reasons that Ortofon prides itself as a premium standard amongst the scores of vinyl DJs still present today.



The manufacturing floor at Ortofon HQ, Nakskov

This document will offer a brief insight into how the four components listed above are made, and what role they play in the end result of sound reproduction.

Body

The body is one of the simplest parts of the system, and the DJ range is split across two distinct styles; the traditional OM headshell-mounted body, and the iconic Concorde tubular body system. Both types of body are made of Noryl, a homogenous mixture of two polymers sourced in by Ortofon. Noryl benefits from being high in rigidity, but low in resonance. It therefore has no distinctive effect on sound output – instead cartridge types are chosen by end users for either 'style', function (i.e. for curved or straight tonearms), record-hold or ease of installation.

Ortofon manufacture and style their bodies on site using hand-operated mechanic processes.



An Ortofon employee prints the design onto Ortofon 'Scratch' stylus bodies

Generator System

There are two principle types of modern pick-up cartridges; moving magnet and moving coil. The moving coil principle is limited to Hi-Fi cartridges only, due to it's expensive manufacturing process and capacity for a more refined 'audiophile' sound-quality. Moving magnet generation works on the reverse basis of moving coil, but can be mass produced, and allows for a more hardwearing, longer living professional cartridge. Essentially, within the cartridge body is a generator system, which is made up of very fine coils that extract an electrical output from a signal provided by a magnet, moving within the stylus body. This method of construction makes the more exposed stylus tip replaceable on a moving magnet cartridge, allowing for the continued life-span of a cartridge body.



At Ortofon, the ultra-fine coils are woven by a machine, uniquely customised by their own engineers. These coils are hand-threaded into a body, which then sits within a metal casing and is linked by four tonearm-style cables (distinctively recognisable as the cartridge tags found on the outside of OM bodies, plugging the cartridge into the headshell). These cables allow the signal to be transferred from the generator system, to the external connections.



Installing generator systems into cartridge bodies

The number of coils, as well as other factors, contribute to varying sound output from different moving magnet cartridges. Accurate output for different purposes (i.e. TCV playback, or more musical playback) is therefore achieved within the main cartridge body.

Connections

Concorde cartridges are designed for easy plug and play in industry-standard pro-DJ turntables, such as the Technics Sl-1200 or Numark TTX models. This is done via a simple aluminium connector which is manufactured offsite for Ortofon, but hand-installed to ensure precise connectivity. The connector takes the tonearm-like wire coming from the generator system, and transmits the signal through four rounded nodules which connect with the plug on your tonearm. This signal eventually reaches a phono stage (either externally, within your turntable, or in your mixer), for amplification to line-level, and musical playback.



It is recommended that users clean their connectors before installing. Ortofon recently changed it's connectors to have flatter, wider nodules to ensure connectivity; however, for optimum performance the cleaner the connection is, the stronger the signal.

Stylus Body

Encased within the stylus body are four parts crucial to the sound characteristics of a cartridge. They are the diamond (or stylus), cantilever, suspension and magnet. The magnet is of neodymium origin and, as previously mentioned, moves in relation to the record wall in order to send a signal to the generator system for amplification. This is mounted on the cantilever, which is connected at the other end to the diamond stylus and mediated in its movement by the rubber suspension (see above image).

Ortofon DJ cantilevers are made of aluminium, and unique in the sense that they are actually made of two tubes. Rather than being one tube, like on a hi-fi cartridges, a thicker tube is mounted on top of a thinner one in order to keep the cantilever stiff through all the additional stresses DJ use requires. Cantilevers are mounted using complex machinery, overlooked by skilled technicians at Ortofon.



Different customised machines take care of the various parts of cantilever construction



The rubber suspension is crucial to the mobility of the cantilever, and is the defining feature in the revolutionary Ortofon-Serato S-120 cartridge. All Ortofon's rubber is created from scratch within their dedicated laboratory, and then cut and moulded by hand under high-powered microscopes.



Ortofon's mini chemistry lab and rollers, used for producing rubber, in sheet form

These three components are sealed together by custom-made machines on the manufacturing floor in Nakskov, and encased within the plastic body for easy fitting to it's Concorde or OM counterpart.



More specially-designed machines fit the rubber suspension

Finally, diamond is considered the substance of choice for reading a record groove, because it is the hardest natural substance known to man. Hardness is a necessity for the stylus as it makes contact with less than one millionth of a square inch of the record surface, and therefore exerts a tremendous pressure on the vinyl. As a consequence, the stylus needs to be hard so it does not degrade. The diamonds are cut to read a record wall in either a spherical or elliptical shape; each offering its own benefits for DJ applications. A spherical (or conical as it is sometimes called) diamond is the least expensive to manufacture, but for DJ purposes is excellent to combat record skip. The more expensive elliptical stylus has a narrower profile, which makes more contact with the record wall allowing for greater musical detail and sound quality.

All Ortofon's diamonds are cut by hand, again under microscopic conditions, in order to get that unique, distinctive sound common to Ortofon. These are then mounted accurately on to the cantilever to complete the stylus body.



Hand-cutting a diamond

The End Product

Finally, these separate component parts are sealed into one piece to make a complete Ortofon DJ cartridge. The functions of these cartridges range from introductory standards, allowing new DJs to develop their scratch and mixing skills, through to pro-grade cartridges specific to either mixing, scratching or playing timecode vinyl.