Here are some general tonearm specifications and what they mean. These are typically provided in the documentation included with most turntables.
Effective Tonearm Length – expressed in millimetres (mm), this is the length of the tonearm distance from the centre of the tonearm pivot to the tip of the stylus. Effective length is equal to the pivot-to-spindle distance plus the overhang. (See the “ToneArm Basic Geometry” diagram at analogplanet.com.) The arc traced by the stylus tip as it moves from the outside to the inside of the record is determined by the tonearm’s effective length.
Cartridge Height Range – expressed in millimetres, this figure tells you the minimum and maximum height (as measured from the bottom of the stylus tip to the top of the cartridge body) that a cartridge can be for the tonearm to remain level (parallel to the record surface) while playing. A level tonearm, and therefore a level cartridge body, ensures that the vertical tracking angle designed into the cartridge will be maintained. Note that this specification is more common with tonearms featuring adjustable tonearm height.
Stylus Overhang – the distance the stylus extends beyond the centre spindle when the tonearm is positioned directly over the spindle. Stylus overhang makes up part of a tonearm’s effective length. A simple way to set overhang is to use a dedicated stylus overhang gauge that has markings in millimetres (mm). It may also be set using an arc protractor, provided the protractor is designed for the specific mounting distance (aka pivot-to-spindle distance) of your tonearm. Note that Audio-Technica headshell/cartridge combo kits come with stylus overhang set at 15.5 mm. Follow the tonearm manufacturer’s guidelines when setting stylus overhang.
Effective Tonearm Mass – tonearm makers rate their arms in terms of effective mass before a cartridge is mounted. Effective mass is influenced by the weight of the various appendages of the tonearm, such as the headshell and counterweight assembly, in ratio to the distance of these appendages from the tonearm pivot. Weight that is farther from the pivot centre will account for higher effective mass than the same weight positioned closer to the pivot. Effective tonearm mass is expressed in grams.
Stylus Pressure Adjustment Range – aka tracking weight or vertical tracking force (VTF) range. Expressed in grams, this figure tells you the minimum and maximum tracking forces that can be applied to the cartridge, based on the minimum and maximum weight of the cartridge after the weight of the cartridge has been counterbalanced. Adhere to the cartridge manufacturer’s guidelines when setting stylus pressure.
Cartridge Weight Range – this figure is expressed in grams, and it should be noted if it includes the weight of the headshell or not. This figure tells you the minimum and maximum weight of a cartridge (or cartridge plus headshell) that can be counterbalanced by the counterweight that is provided with your turntable.
Headshell Weight – expressed in grams, this is the weight of the headshell itself for those tonearms featuring a removable headshell. Note that the effective mass of the tonearm can be altered by changing the headshell out to a lighter or heavier weight headshell. Effective mass may also be altered by changing the counterweight out for a lighter or heavier counterweight if one is available for your tonearm.
Vertical Tracking Angle (VTA) Adjustment – expressed in degrees, vertical tracking angle is the angle between the record surface and the axis of the cantilever pivot point to stylus contact area. The vertical tracking angle affects stylus rake angle (SRA), which is the front-to-rear rake of the stylus within the groove. VTA can be adjusted, most commonly, by raising or lowering the pivot end of the tonearm, although other methods do exist. Most cartridges are designed so that their intended VTA is achieved when the top of the cartridge body is level in the horizontal plane (parallel to the record surface) while playing.
Azimuth Adjustment – expressed in degrees, azimuth (aka tilt) is the angle between the surface of the record and the vertical axis of the cartridge as seen from the front. This angle should be 90° to ensure optimal channel balance. Some tonearms feature an azimuth adjustment where the tonearm tube can be rotated to adjust azimuth, others may feature an azimuth adjustment on the headshell. Good azimuth becomes more critical as the vertical contact patch of a stylus (this is the side of the stylus which contacts the record grove wall) becomes taller. Our microlinear, Shibata, and special line contact styli fall into this category.
Tonearm Mounting Distance – aka pivot-to-spindle distance. This is the length of the tonearm distance from the center of the tonearm pivot to the center of the spindle. The mounting distance is equal to the effective length minus the overhang.
Here are some general cartridge specifications which can be found in the documentation included with most cartridges.
Cartridge Dimensions – it is helpful to know the cartridge height so you can determine if your tonearm will accommodate it as is, or some adjustments will need to be made. The tonearm should be level in the horizontal plane (parallel to the record surface) while playing to ensure the vertical tracking angle designed into the cartridge is achieved. If your tonearm does not feature adjustable height, shims can be used between the top of the cartridge and the headshell to level the tonearm and the top of the cartridge if the cartridge is too short. A thicker record mat can help with this also. A thinner mat can help with a cartridge that is too tall. Cartridge dimensions are expressed in millimetres (mm).
Cartridge Weight – expressed in grams, this is the weight of the cartridge itself. It does not include the weight of any associated mounting hardware, such as screws and nuts.
Compliance – expressed in compliance units (cu), compliance is a measure of the springiness of the stylus assembly’s suspension system, with high compliance meaning a soft suspension and low compliance meaning a stiff suspension. A cartridge having low compliance (less than 10 cu) is suitable for a high effective mass tonearm (26 g or more), one having medium compliance (10 to 20 cu) is suitable for a medium mass tonearm (11 to 25 g), and one having high compliance (greater than 20 cu) is suitable for a low mass tonearm (10 g or less).
Vertical Tracking Force (VTF) – aka tracking weight or stylus pressure. Expressed in grams, this is the downforce the counterweight applies to the cartridge’s stylus. Adhering to the manufacturer’s recommended tracking force range ensures proper stylus contact with the record groove walls and proper loading of the stylus suspension system. Staying within this range will help preserve stylus and record life, provide optimum sound quality, and produce the lowest amount of tracing distortion possible.
If you have any questions regarding the selection of a cartridge for your turntable, please contact us.