32

Cartridge-making Dictionary Audio-Technica’s guide to cartridge-making terminology

33rpm Bonded diamond Channel Balance Connecting (the phono cartridge) very often denotes 12” LP Vinyl records Bonded diamond refers to a The channel balance of a cartridge is the (1949-Today), that should be played at stylus where the diamond tip is ability of the transducer to reproduce left a speed of 33 1/3 rpm, rpm stands for glued on a metal shank that is and right channels in the same manner. Rotation Per Minute. itself glued into the hole of the Channel balance should be part of the cantilever. This construction may cartridge specifications, it expresses the 45rpm increase the mass of the overall tip and possible output difference in dB from one 45rpm very often denotes 7” Vinyl records, affect transient reproduction compared channel to another. A cartridge with ideal (1949-Today) that should be played at a with nude styli that are preferred and used channel balance will playback any mono speed of 45rpm, rpm stands for Rotation on higher-priced models. signal with equal level in both channels. Per Minute. The channel balance will be 0dB. The ratio of the signals between the two channels To install a Phono cartridge, connect the 78rpm Boron (boron cantilever) is specified in dB. Channel imbalance four wires of the cartridge headshell to the 78rpm very often denotes 10” Shellac SP Boron is a chemical element from the can result in several factors independent correct terminals on the back of the Gramophone records (1925-1950) that metalloid family, extracted from Borax and from the cartridge itself: mechanical cartridge. should be played at a speed of 78rpm, rpm Kernite. Its atomic number is 5. Boron is factors include incorrect azimuth settings, The four wires are colour-coded and stands for Rotation Per Minute. used for high-end cantilevers due to its misalignment of the tonearm and/or of the generally labeled as follows : lightweight and high-rigidity properties. cartridge on the headshell, and/or improper Left Channel: White Anti-skating It reaches a score of 9.5 on the Mohs anti-skating adjustment. Left Channel Ground: Blue When the record is in play, the friction hardness scale (for reference Diamond Other Channel imbalance issues, Right Channel: Red between the stylus in the groove of the scores 10 and Aluminium 3). independent from the cartridge or the Right Channel Ground: Green record and the length of the arm (the turntable, could include mismatched distance between the tip and the arm cables, electronic elements such as stereo Conical bearing) creates a force that pushes the Cantilever (stylus cantilever) , speaker system, speaker (form factor of the diamond cartridge toward the center of the disk. positioning and/or room acoustics. stylus) Anti-skating creates a force that pulls Also called spherical, because of the arm towards the outer edge of the Channel Separation the shape of the tip of the cone. disc to compensate it. Because records The channel separation of a cartridge is Conical shaped stylus are simple don’t have a constant amplitude, a static the ability of the transducer to deliver only to produce, therefore it becomes the most compensation will never totally cure the signal on the left channel of the cartridge, popular when economy is a factor. problem. It is a matter of balance. Badly set and nothing on the right channel when anti-skating will produce channel balance there is only signal on the left channel Counterweight Cantilever and distortion issues. When the anti- groove,and vice versa. Channel separation (Tonearm Counterweight)

skating is set too high, the left channel will Styli are principally made of three is frequency dependent. Audio-Technica Arm rest distort during loud passages, while on the components: Stylus Tip, Stylus Cantilever, indicate in the specifications the Channel other side if it’s too low, the right channel and Stylus Suspension. separation, specified at 1kHz. For high- Quad lead will distort. Also the amount of anti-skating The cantilever is a tiny suspended “arm” end cartridges, Audio-Technica provides wires depends on the shape of the tip. Conical (solid or pipe) that holds the Diamond Tip channel separation curves, showing the Headshell Anti-skating stylus tends to require more anti-skating on one end and transfers the vibrations to separation in dB from 20Hz to 20,000Hz. Tonearm device (due to the amount of friction generated the other end where the (in case A high channel separation provides a better base by their shape) than more complex shapes of MM cartridges) or the Coils (in case of stereo image. (Line contact or Micro linear). MC cartridges) are housed. Arm rest Different materials are used to make a Compliance Tracking force fine adjustment Tonearm Azimuth (see also Tilt) cantilever: Aluminium, Saphyr, Beryllium, Compliance is the inverse of stiffness. weight counter weight For magnetic tape drives, azimuth refers boron... The lighter and stiffer being the Every cartridge works as a suspension, a to the angle between the tape head and best. high compliance cartridge will be suited for magnetic tape. For phono cartridges, a low mass tonearm and a low compliance Dual Moving cartridge Azimuth is the angle between the surface Cartridge (Phono Magnetic Cartridge) (stiffer) cartridge will be suited for a high Audio-Technica’s patented Vertical of the record and the vertical axis of the The phono cartridge is the transducer used mass tonearm. Dual Magnet phono cartridge, unlike cartridge. for the playback of gramophone records. There is not a perfect compliance number, conventional cartridges, use the 90° Note the difference between cartridge The phono cartridge converts the the cartridge compliance together with the V-Shape of the cutter head. The standard removable head shells: some models mechanical energy (vibrations) from a effective mass of the tonearm/cartridge cutter head (used to record the vinyl such as the “Technihard series” (page stylus riding in a record groove into an combination determine the tonearm’s master) uses two transducer coils, 30) feature an “azimuth” adjustment. This electrical signal that will be amplified then fundamental resonance. mounted perpendicular to each other at feature is particularly useful when it is not processed, recorded, or played through a For optimal results the frequency should be 45° from horizontal, to cut the channel: provided by the tone arm itself. sound system. maintained between 9-13Hz. one in each wall of the 90° record groove. 33

Cartridge-making Dictionary Audio-Technica’s guide to cartridge-making terminology

This way, the cartridge achieves accurate Line contact that it allows a contact surface of around As magnet vibrates in response to the tracking, excellent channel separation, high (form factor of specific stylus 115 μm2. The shape is “similar” to other stylus following the record groove, it definition of the stereo image and extreme diamonds) Audio-Technica uses diamond tips such as SAS, Dynavector or induces a tiny current in the coils. clarity over the entire audio spectrum. Line Contact shape stylus on Namiki. several high-end cartridge styli. The MicroLine™ diamond is different from Mu-metal (shielding) Elliptical The tip of the diamond is such Line Contact diamonds, also featured on Mu-metal is a range of nickel-iron alloys (form factor of the diamond that it allows a contact surface between 50 high-end styli. Line Contact tips are also that are notable for their high magnetic stylus) and 75 μm2. The shape is “similar” to other known as “Shibata”, providing a contact permeability. The high permeability makes An Elliptical stylus is produced diamond tips known as Shibata. surface between 50 and 75 μm2. mu-metal useful for shielding against static starting from a Conical Stylus, or magnetic fields. then two cuts are made in order Load MM input Mu-metal is frequently used to protect low to make the vertical contact When connected to a phono preamp, the MM stands for Moving Magnet: an MM input signal transformers such as the ones found longer and the front to back contact cartridge forms a RLC (Resistor, Inductor, denotes the input stage of a is on microphone preamplifier input stages narrower. Capacitor) circuit which acts as a resonant able to handle the signal of a Moving magnet or on the Cartridge step-up transformers The elliptical tip follows the groove filter emphasizing certain frequencies phono cartridge and the MM input also has used with MC cartridges. modulation with more precision than a while reducing others. In order the achieve an input impedance suitable for the output Several models of Audio-Technica conical tip, improving frequency response, to most linear frequency response, impedance of MM cartridges. cartridges use Mu-metal shielding between phase response, and lowering distortion, manufacturers specify several load values the left and right sections of the cartridge specifically in the inner turns of the record. (load capacitance, load impedance and so Monaural in order to improve channel separation. on). By following these specifications for Monophonic sound reproduction (often Frequency Response the choice of the phono stage, one can called mono) is single-channel audio Neodymium Frequency response is the quantitative achieve the best sonic results. program material or single channel audio Neodymium is used as a component in measure of the output spectrum of the reproduction. Monaural recording on vinyl the alloys used to make high-strength, cartridge in response to the stimulus of the LP Record has been replaced by stereo sound during powerful permanent magnets (neodymium record grove modulation. LP stands for Long Play or 33 rpm the mid 60’s. 78rpm records and Vinyl magnets). These magnets are widely used It is a measure of the magnitude for the microgroove vinyl record format. Introduced records from 1952 to 1960 are Monaural. throughout the audio industry in products output as a function of frequency; typically by Columbia Records in 1948, it was Stereo sound on vinyl records was such as microphones, professional measured in decibels (dB). In the case of adopted in the mid-fifties as a new standard introduced in 1958. , or in-ear , where cartridge measurement, the input signal by the entire record industry. It became low magnet mass or volume, and strong will be a constant-amplitude pure tone stereophonic in the mid 60’s and is still the Moving Coil cartridges magnetic fields, are required. through the bandwidth provided by a standard format of vinyl albums today. The MC design is a tiny electromagnetic reference record. generator, but as opposed to MM design, Nude Shank diamond Magnetic cartridge (see cartridge) the 2 coils are attached to the stylus (the Nude diamond refers to a Impedance moving part), and move within the field of stylus when the diamond glued The impedance is a measure of the MC phono input a fixed permanent magnet. The coils are into the hole of the cantilever is total opposition that a circuit presents MC stands for Moving Coil. A Phono Input much smaller than MM cartridge coils and made out of one single piece of to alternate electric current. The output on a preamplifier or mentioning made from very thin copper wire. diamond. impedance of an electronic device is the MC means that the characteristics of This result in a low impedance, low output Nude This construction as opposed impedance of its internal circuit “seen” by the preamplifier input stage, in terms of signal but on the other hand it is also very to Bonded shank (jointed) any device connected to its output. The Input impedance, Gain and de-emphasis lightweight allowing for a better response improves the mass of the Input impedance of an electronic device equalisation are such that it will allow you and a more detailed reproduction. overall tip and, because the is the impedance “seen” by any source to use a Moving Coil Phono Cartridge by Moving coil cartridges are extremely small vibrating signal does not connected at its input. plugging it into this input. precision devices and as a consequence have to transfer through two Input impedance of the phono preamplifier they are considerably more expensive, Bonded different materials, provides and output impedance of the cartridge Micro linear (form factor of a stylus but are preferred by due the best possible transient should be properly matched to achieve diamond, see MicroLine™) to measurable and subjectively better reproduction. Nude styli, although optimal sound. An impedance mismatch A specific shape of a diamond stylus, Micro performance. expensive to produce, are preferred and will work as a filter and degrade the sound linear refers to a particular “ridge shape” used on the higher priced models. making it dull or harsh depending on the stylus. An Audio-Technica trademark, Moving Magnet cartridges setup. A general rule of thumb is that the Micro linear styli are known as MicroLine™. The MM design is a tiny electromagnetic Output Voltage (of a cartridge) input impedance of your phono preamp generator, but as opposed to the MC Amplitude in mV of the electrical signal (also referred to as the load impedance MicroLine™ (moving coil) design the stylus cantilever delivered by the cartridge for a given of your cartridge) should be 10 times the Audio-Technica Trademark which carries a pair of small permanent magnets. standard program material of the record output impedance of your cartridge (also denotes the Micro linear “ridge” Those magnets are positioned between grove. Knowing the Output voltage is called the source impedance). shape stylus. two sets of fixed coils forming the tiny an important factor: it will inform of the The tip of the diamond is such electromagnetic generator. characteristic of the Phono input needed in 34

Cartridge-making Dictionary Audio-Technica’s guide to cartridge-making terminology

order to accommodate a given cartridge. Phono Preamp the cartridge wiring or mechanical position, Spherical (diamond, see conical) Output voltages may vary from under Denotes a preamplifier with an input or a to replace only the Stylus assembly instead 0.1mV for the least efficient Moving Coil series of inputs capable of handling the of the complete cartridge. Square Shank models on the market, up to 5mV for very output from a Phono cartridge. Square shank styli cost more efficient Moving Magnet cartridges. Such As opposed to a “standard” line input RIAA than round shank to make but differences of more than 30dB shows that preamp such as a Microphone input RIAA stands for: Recording Industry mounting them in laser cut holes when selecting a cartridge, the selection of preamplifier, the Phono Preamplier Association of America (RIAA), the trade in the cantilever locks them the associated preamplifier, with or without will provide the necessary gain, Input organization that represents the recording precisely in correct alignment step-up transformer, is essential. impedance matching to the output industry in the United States. Early RIAA with the record groove. This is the reason impedance of the cartridges, and the standards included the RIAA equalization why they are used for shapes that need a Overhang (Cartridge overhang adjustment) de-emphasis equalisation needed to curve, the format of the stereophonic record precise orientation (Line Contact, support the signal originated from the groove and the dimensions of records. MicroLine™). phono cartridge playing a record. In the case of a Vinyl record, the RIAA equalization equalisation will usually be RIAA. is a specification for the recording and Step-up Transformer playback of records. The An MC cartridge has both a low output Overhang adjustment Phono Cartridge (see Cartridge) purpose of the equalization is to permit voltage (generally below 1mV) and a In the case of cartridges mounted on a greater recording times, improve sound low output impedance compared to a removable headshell, it could be necessary Phono input quality, and to reduce the groove damage MM cartridge. The role of the step-up to adjust the cartridge by several Denotes the pair of input connectors (L&R) that would otherwise arise during playback. transformer is to raise the output voltage millimeters in order for the stylus to be of the Phono Preamp. RIAA equalization is a form of pre- while, at the same time, match the required properly aligned with the tangent of the emphasis on recording and de-emphasis impedance between your cartridge and the groove. Older tonearms provide adjustment Pole Piece on playback. A recording is made with phono preamplifier. on their bases in order to perform a proper The pole piece is a structure composed of the low frequencies reduced and the high setting using a tonearm protractor material of a high magnetic permeability frequencies boosted, and on playback the alignment system. Most modern tonearms that serves to direct the magnetic field opposite occurs. Stylus Holder (Stylus Assembly) do not provide this feature. In such a case, produced by the magnet. A pole piece The plastic part of an interchangeable it is important to be able to adapt the attaches to and, in a sense, extends a pole RIAA input stylus that holds the cantilever and the distance between contact point of the of the magnet, hence the name. (Also known as Phono input) vibrating part, both forming the Stylus stylus and axis of the tonearms with the Input of a preamplifier section providing assembly. Overhang adjustment provided by the Radius (stylus Radius) the de-emphasis equalization needed to On Moving magnet cartridges, the cartridge headshell. The radius of a stylus is the distance (R) support the signal originating from a phono removable stylus assembly is held in place in either mil (thousandth of an inch) or μm cartridge playing a vinyl record. (Note: on the cartridge casing. (micro, 10^-6, of a meter). The conical Most 78rpm shellac records produced after stylus has a unique Radius which varies 1942 can be played with RIAA equalization, from 0.6 to 0.7 mil for Vinyl records. (2, nevertheless we recommend you check Tilt (see also Azimuth) Tonearm protractor 2.5, 3, or 3.5mil for shellac records). The the nature of the pre-emphasis used by the elliptical stylus has two radii, R1 and R2, record company.) Tilt adjustment Para-toroidal coil for the front and side. Standard elliptical Para-toroidal coils are used on high-end Styli are around 0.3 x 0.7 mil. Due to the Round Shank Moving Magnet Audio-Technica cartridges, complexity of line contact and MicroLine™ Specifically the shape of the providing better channel separation, styli, their radius value is not always an shank where the tip is fitted. channel balance and improved transient accurate description of their shape and size. Round shank is generally used response. Para-toroidal inductors are for shapes that require no or passive electronic components, widely Replacement Stylus minimal orientation (round, Tilt is the angle between the surface of the used for transformer construction. The Stylus assembly of Moving Magnet conical elliptical) record and the vertical axis of the cartridge. inductor with a closed-loop core can have cartridges are field replaceable. This angle should be 90° in order to insure a higher magnetic field and thus higher When the diamond is worn out, (between Shellac record optimal channel balance. inductance and Q factor than similarly 600 and 1000 hours) or if the cantilever Shellac records are also described as constructed coils with a straight core. becomes damaged, the stylus assembly 78rpm records or SP (Short Play) The advantage of the toroïdal shape is needs to be replace. Tracking Force that due to its symmetry, the amount of The Stylus assembly represents between SP record (see Shellac record) To play back a vinyl disc, the stylus must magnetic flux that escapes outside of the 60% to 80% of the cost of a complete SP stands for Short Play denoting 78 rpm make good contact with the walls of the core (leakage flux) is minimum; therefore it cartridge (depending on the nature of the Shellac records, as opposed to LP (Long record groove. radiates less electromagnetic interference diamond tip). It makes sense, not only for Play) denoting 33 1/3 rpm microgroove Excessive down force (tracking force or to nearby circuits or equipment. economic reasons but also to avoid work on vinyl records. tracking weight) will both wear and not 35

Cartridge-making Dictionary Audio-Technica’s guide to cartridge-making terminology guarantee that the stylus will perfectly follow Vinyl (see also LP record) molecule is PVC (Poly Vinyl Chloride), the VM™(see Dual Magnet cartridge) the record grove. Vinyl for most people denotes a 12 inch, plastic commonly known as vinyl. Audio-Technica specifies the tracking 33rpm, microgroove LP record. Vinyl was used for the first time to produce force, for each cartridge, as a range of The word Vinyl comes from the chemical form records by Columbia in 1946. During the early recommended values in grams. of the material used to produce LP records: 50’s the Vinyl record replaced the 78 rpm A cartridge given insufficient tracking force vinyl chloride. Shellac SP record as the standard. is more likely to cause damage to the groove An important industrial application of this wall than one whose tracking weight is set at the high-end of the recommended range. The cartridge could lose contact with the groove wall, or “jump”, causing damage to the record as it bounces trying to regain contact. Understanding the sizes and shape of Audio-Technica stylus tips and the contact area in the record groove

Tracking weight (see Tracking force) Stylus sizes 0,6mil 0,2 x 0,7mil 0,3 x 0,7 mil Stylus shape Conical stylus Elliptical stylus Elliptical stylus Line Contact stylus Shibata MicroLine™ stylus Transient Response The transient response is the behaviour of a R R system when a signal is changing from one = 40 m R Stylus front view R R µ value to a specified higher value. R Rise time (the time required for the signal to change) and Overshoot are among the most R R R r = important parameters entering under the r = r = R r = r Stylus horizontal 0,3mil generic definition, Transient response. R = 0,2mil 7µm 5µm A transducer having a good transient cross-section 0,6mil response will result in perceiving that r = 15,25µm the music material is sharp, with fast AT-ART9 accelerations, capable of reproducing Audio-Technica AT33MONO AT-OC9ML/II AT-F7 AT33EV AT-OC9/III AT33sa accurately and in a realistic manner the moving coil cartridges AT-MONO3/LP AT33PTG/II AT-ART7 fastest impulses of musical instruments. On a record, the signal is present in the Audio-Technica moving AT5V AT120Eb AT150MLX grove, the cartridge is transforming the magnet cartridges AT91 AT100E - AT95E AT440MLb mechanical groove of the record into an Audio-Technica electrical current, and the transient response AT3482P moving magnet AT311EP of the cartridge will essentially respond to AT300P P-mount cartridges fast changing sound waves present into the groove. Dimensions (see R=0,7mil = 17,8mm R=0,7mil = 17,8mm R=40mm R=75mm R=75mm Under Transient response, the capacity of R=0,6mil = 15,25 m horizontal cross section) m r=0,2mil = 5,08mm r=0,3mil = 7,6mm r=7mm r=5mm r=2,5mm the moving parts such as cantilever/stylus/ tension spring assembly to be controlled D2 D2 and not to produce parasitic oscillations is Contact surface D2 D2 D2 D2 also part of the transient response quality. on record groove D1 D1 D1 D1 D1 D1 The capacity of the system after changing to (stylus side view) revert to its equilibrium is also important.

Vertical Tracking Angle Approximative contact D1/D2=1 D1/D2=1,85 D1/D2=1,60 D1/D2=2,25 D1/D2=3 D1/D2=6 Vertical Tracking Angle is the angle between dimensions ratio the record surface and the axis “cantilever- pivot-point” to “stylus-contact-area”. (1) D2 represents the contact dimension at the horizontal plane while D1 shows the contact dimension at the vertical plane. These two dimensions indicate the contact area between the record groove walls and the stylus tip. D2 must be as small as possible to track small groove variations (high frequency). The total contact area should as large as possible to minimize Pivot point record wear and maximize accurate reproduction. The larger the area, the smaller pressure from the cartridge on the record; as opposed to the smaller the area, the more pressure is Vertical tracking applied on a specific point of the groove, leading to record wear. angle We can see from the above table that the Line Contact and Micro linear shapes offers a smaller horizontal contact area leading to superior precision and high frequency transcription, while offering a larger contact area than conical and elliptical styli due to taller a vertical contact area minimizing record wear.