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Phono Magnetic Cartridges
Piezoelectric (crystal/ceramic) cartridges
Early electronic phonographs did not use phono magnetic cartridges but used a piezo-
Crystal pickups are relatively robust, and yield a good level of signal which requires only a modest amount of amplification. A crystal's output tends not to be very linear, introducing unwanted distortion. It is difficult to make a crystal pickup suitable for stereo reproduction, as the stiff coupling between the crystal and the stylus prevents close tracking of the needle to the groove modulations. This tends to increase wear on the record, and introduces more distortion.
The next development was the ceramic cartridge, a piezoelectric device that used newer materials to replace the crystal. These were more sensitive, and they offered greater compliance, the lack of resistance to movement and the ability to ride the undulations of the groove without distorting or jumping out of the groove.
Higher compliance meant lower tracking forces and reduced wear to both the disc and
stylus. It also allowed ceramic stereo cartridges to be made. The ceramic cartridge
became standard in most phonographs, except for the better high-
Want to know more about Phono cartridges? -
Phono Magnetic cartridges
There are two types of phono magnetic cartridges, moving magnet (MM) and moving coil (MC) (originally called dynamic). Both operate on the same physics principle, that of electromagnetic induction. The moving magnet type is by far the most common and more robust of the two, though audiophiles often claim that the moving coil system yields higher fidelity sound.
In either type of phono magnetic cartridges, the stylus itself, usually of diamond, is mounted on a tiny metal strut called a cantilever, which is suspended using a collar of highly compliant plastic. This gives the stylus the freedom to move in any direction.
On the other end of the cantilever is mounted a tiny permanent magnet (moving magnet
type) or a set of tiny wound coils (moving coil type). The magnet is close to a set
of fixed pick-
In either case, the movement of the stylus as it tracks the grooves of a record causes a fluctuating magnetic field which causes a small electrical current to be induced in the coils.
This current closely follows the sound waveform cut into the record, and may be transmitted
by wires to an electronic amplifier where it is processed and amplified in order
to drive a loudspeaker. Depending upon the amplifier design, a phono-
In most phono magnetic cartridges, the stylus itself is detachable from the rest of the cartridge so it can easily be replaced. There are two primary types of cartridge mounts.
The older type is attached using small screws to a headshell which then plugs into
the tonearm, while the other is a standardized "P-
Styli and the amplifier
The stylus, or "needle", is a crucial part of the phonograph, as it is the one part of the system that actually contacts the recorded disc and transfers its vibrations to the rest of the system.
There are two desired qualities in a stylus: first, that it faithfully follow the contours of the recorded groove and transfer the vibration to the system, and second, that it not damage the recorded disc.
Early phonograph styli in mechanical players were just steel needles, usually with a shank about 1/8" (3 mm) in diameter, ground to a sharp point. These were easily replaceable by the user, as they had a very limited life and wore out fairly rapidly with use. Extensive play tended to wear records out as well as needles.
When the electronic phonograph was introduced, styli were included as part of the
pickup cartridge. Early ones were tipped with either sapphire or osmium, with diamond
available as a premium, long-
Typically, these early cartridges were of the "flip-
The entire cartridge could be rotated 180° by means of a knob or lever at the end of the tonearm to use the desired stylus. (A later refinement was a stylus, clipped to a stationary cartridge, that could be flipped over to use one of two opposing styli cemented to the cantilever.)
Later, starting in the 1960s, most manufacturers settled on diamond-
Specially-
Phono Pre-amplifiers
Phonograph recordings are made with high frequencies boosted. This reduces background
noise, including clicks or pops, and also conserves the amount of physical space
needed for each groove, by reducing the size of the larger low-
The signal given by the phono magnetic cartridge is, therfore, very low, but during
playback the high frequencies are rescaled to their original level. This is accomplished
in the amplifier with a phono input that incorporates standardized RIAA equalization
circuitry -
By 2006, only few
stereo amplifiers retained this PHONO input, since most users were expected to use
digital music formats such as CD or satellite radio. However, the good news is some
newer turntables these days do include built-
You can find details where you can obtain yours at our Phono Pre-
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