Everything you need to know about cartridges: Cartridge mounting

CARTRIDGE MOUNTING

It is not usually difficult to mount or replace a cartridge. The cartridge body itself is fastened to a headshell or mounting plate by two screws on 12,7mm spacing (½”) spacing. Many Hi-Fi turntables and tonearms are also equipped with internationally standardized headshells with bayonet sockets, making it easy to change between cartridges mounted in such headshells.

The user instructions for the turntable or tonearm in question should always be followed carefully when mounting a cartridge. A few general tips are given below.

1. When possible, the cartridge’s stylus unit should always be removed while mounting takes place.
2. Always use fixing screws that are as short as possible. Screws that are too long will only increase the tonearm mass.
3. Colour code for cartridge connecting wires. (Fig. 16.)
   White - left channel (L)
   Blue - left channel ground (LG)
   Red - right channel (R)
   Green - right channel ground (RG)
   
   

   Fig. 16. Connecting pins and colour code of a typical Hi-Fi cartridge.

4. The cartridge lead wires should be fixed to the contact pins carefully with the help of a pair of pincers, making sure that the clips are making a tight contact. (Fig. 17.). They should be crimped, if necessary, to make them tight. The wires for each channel should also be wound together to avoid hum pick up. This is specially important in the case of the moving coil cartridges.
   
   

   Fig. 17. Cartridge wires are mounted carefully on the connecting pins using a pincette. Where possible, the stylus unit should be removed while this takes place.

In the majority of headshells, the cartridge can be adjusted in order to ensure the least possible tracking error and distortion in playback. This adjustment can be made with the help of a tracking alignment protractor, as illustrated below, where the cartridge stylus is placed on the spot marked X, and the sides of the headshell follow the lines on the protractor. (Fig. 18)

Fig. 18. An alignment protractor is used to find the correct distance from stylus tip to tonearm pivot. When the cartridge’s longitudinal axis is parallel with the horizontal lines, tracking error will be at a minimum.

Tracking force and antiskating

The majority of cartridge manufacturers give a tracking force range for their cartridges, i.e. a high and low limit for the tracking force. Many also give a recommended tracking force which will be suitable for most situations. If in doubt, it is wisest to let the cartridge operate with at least the recommended tracking force, as records wear faster when played with too low a tracking force than with too high a tracking force. Specially demanding records may make it necessary to adjust the tracking force to the maximum value, or maybe even more. However, the cantilever suspension will be damaged very quickly if the cartridge is used for longer periods with a tracking force that is higher than the stated maximum; and on warped records, there is a risk that the cartridge’s stylus unit will knock against the record.

The purpose of the antiskating adjustment in quality tonearms is to create an even contact force for the cartridge stylus on both sides of the record groove, thus keeping distortion and record wear at a minimum. Where the antiskating scale is calibrated in grams, the adjustment should, as a rule, be the same as the tracking force adjustment. However, it may be necessary to experiment with antiskating in order to limit distortion during playback of powerfully modulated records. Distortion which appears in one channel only may be due to improper adjustment of antiskating force.