MM (moving magnet) pickup

Advantages:
• inexpensive
• replaceable needle
• compatible with Phono MM inputs

All cartridges with a moving magnet take advantage of Faraday's law of electromagnetic induction. It states that a conductor placed in a changing magnetic field will have an electromotive force induced proportional to the rate of change of the field. If a permanent magnet is suspended at or near the poles of an iron-core coil, the coil will produce the required variable magnetic flux as the magnet is moved. A cantilever arm transmits the mechanical vibrations picked up by the needle from the record groove directly into the permanent magnet. This creates an electromagnetic field that changes in direct proportion to the mechanical vibration. In this way, the audio signals contained in the record groove are converted into tiny electrical currents, which are then amplified and reproduced through the speakers.

The cartridge must be connected to a phono amplifier input via the tonearm cable so that the low voltage produced by the system (typically 5 mV) is boosted to several volts. Goldring's MM systems have a relatively high output voltage and require a load impedance of 47 kΩ. This makes them compatible with the MM phono input that is standard on many amplifiers. If your amplifier does not have an MM phono input, you can purchase appropriate phono preamplifiers separately.