The Cartridge - Moving Magnet or Coil

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How a cartridge operates

A cartridge operates by transforming the mechanical movement of the stylus / cantilever assembly into an electrical signal.

The performance of the cartridge is dependant upon the various materials used to construct the frame or body of the cartridge. The body or frame can be manufactured using moulded plastic, CNC machined aluminium, and in some very high end cartridges exotic woods or semi precious stones.

Also important is the profile of the diamond tip of the stylus, the material used to form the cantilever plus the magnet or coil attached to the cantilever indicating whether the cartridge is a Moving Magnet or Moving Coil design.

In an ideal world, only vibrations from the record groove would be transformed into electrical energy, but the stylus also has to deal with structural and airborne vibrations which effect its performance.

Vibrations from the record groove travel from the stylus tip up and along the cantilever to the magnet or coil which in turn vibrate between the cartridges magnet or coil assembly creating an electrical output voltage.

The Moving Magnet Cartridge

A moving magnet design utilises a pair of miniature magnets fitted to the end of the cantilever.

Vibrations from the record groove travel from the stylus tip up and along the cantilever to the pair of magnets which in turn vibrate between the cartridges fixed pair of coils creating a high electrical output voltage.

Hence the name Moving Magnet.

Connected to the pair of coils are the positive and negative connections for the Left & Right channels.

Left Positive = White 

Left Negative = Blue

Right Positive = Red

Right Negative = Green 

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The Moving Coil Cartridge

A moving coil design utilises a pair of fine wire miniature coils fitted to the end of the cantilever.

Vibrations from the record groove travel from the stylus tip up and along the cantilever to the pair of coils which in turn vibrate between the cartridges fixed pair of magnets creating a low-impedance, low-output voltage.

Hence the name Moving Coil.

Connected to the fixed pair of magnets are the positive and negative connections for the Left & Right channels.

Left Positive = White 

Left Negative = Blue

Right Positive = Red

Right Negative = Green

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Moving Magnet designs

Moving Magnet designs are compatible with a vast range of tonearms. They are far cheaper to manufacture and easier to repair as the manufacturing process is less complex compared to a Moving Coil design.

The Moving Magnet design generates a higher output voltage due to the fixed pair of miniature magnets fitted to the end of the cantilever.

Unfortunately there is a compromise as the magnets mounted onto the cantilever are heavier than the coils used in the Moving Coil design and as such reduces the assemblies ability to track the more subtle vibrations recorded within the records groove.

Moving Coil Cartridge

(Reasons why a Moving Coil cartridge is more expensive than a Moving Magnet) 

The stylus / cantilever / fine wire coils and fixed magnet assembly of the Moving Coil design is far more delicate when compared to a Moving Magnet design requiring a highly skilled level of expertise and precision to manufacture and repair.

The Moving Coil design offers the advantage of a very lightweight stylus / cantilever / fine wire coil assembly.

It is far more responsive to tracking the recorded vibrations within the groove of the record offering improved tracking accuracy, transient and high frequency response with less distortion and a far more detailed reproduction overall.

Due to the light weight miniature fine wire coils attached to the cantilever the assembly produces a low level output voltage which requires a dedicated Moving Coil amplification circuit within a phono stage to amplify the low level signal to the line level input of your amplifier.

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There are three types of Moving Coil Cartridges 

  1. Low Output Moving Coil 
  2. Medium Output Moving Coil
  3. High Output Moving Coil 

 The output voltage of the moving coli assembly measured in milli-volts (mV) can range between 0.3 mV and 2.8 mV

Low Output Moving Coil  

Small size coil assembly = Low Output Voltage

Output Voltage: 0.3millvolts to 0.7millivolts

Cartridge Impedance: 5 ohms - 32 ohms

Low output moving coil cartridges are by far the fastest and most responsive to the constantly varying width and depth of the vinyl groove.

They produce a signal with less harmonic distortion and a more open and dynamic sound presentation. 

This is due to the miniature and extremely light weight coil attached to the cantilever.

The down side is that with the decrease in weight there is also a decrease in the output voltage of the cartridge.

Medium Output Moving Coil

Medium size coil assembly = Medium Output Voltage

Output Voltage: 0.7millvolts to 1.0millivolts

Cartridge Impedance: 5 ohms - 32 ohms

Medium output moving coil cartridges have a slightly slower response time due to an increase in size and weight of the coil attached to the cantilever.        

But do provide an increase in their output voltage.

High Output Moving Coil 

Large size coil assembly = High Output Voltage

Output Voltage: 2.8 millivolts 

Cartridge Impedance: 1000ohm

High Output Moving Coil cartridges offer the benefits of a moving coil assembly but also offer a higher output voltage 

which can be connected directly to the Moving Magnet input of your integrated amplifier.

This can be seen as an alternative to purchasing a dedicated Moving Magnet / Moving Coil, Phono Stage and can be a less costly method.