Specification
audio-technica phono cartridges guide - 2019/20 - 55
Cartridge-making dictionary Audio-Technica’s guide to cartridge-making terminology
is that the input impedance of your phono preamp (also
referred to as the load impedance of your cartridge)
should be 10 times the output impedance of your
cartridge (also called the source impedance).
Load
When connected to a phono preamp, the cartridge
forms a RLC (Resistor, Inductor, Capacitor) circuit which
acts as a resonant filter emphasizing certain frequencies
while reducing others. In order the achieve to most linear
frequency response, manufacturers specify several load
values (load capacitance, load impedance and so on).
By following these specifications for the choice of the
phono stage, one can achieve the best sonic results.
LP Record
LP stands for Long Play or 33rpm microgroove vinyl
record format. Introduced by Columbia Records in 1948,
it was adopted in the mid‑fifties as a new standard by
the entire record industry. It became stereophonic in the
mid 60’s and is still the standard format of vinyl albums
today.
Magnetic cartridge (see cartridge)
MC phono input
MC stands for Moving Coil. A Phono Input on a pre‑
amplifier or Amplifier mentioning MC means that the
characteristics of the preamplifier input stage, in terms
of Input impedance, Gain and de‑emphasis equalisation
are such that it will allow you to use a Moving Coil Phono
Cartridge by plugging it into this input.
Micro linear (form factor of a stylus diamond, see
Microlinear)
A specific shape of a diamond stylus, Micro linear refers
to a particular “ridge shape” stylus. An Audio‑Technica
trademark, Micro linear styli are known as Microlinear.
Microlinear
Audio‑Technica Trademark which denotes
the Micro linear “ridge” shape stylus.
The tip of the diamond is such that it allows
a contact surface of around 115 μm2. The
shape is “similar” to other diamond tips
such as SAS, Dynavector or Namiki.
The Microlinear diamond is dierent from Line Contact
diamonds, also featured on high‑end styli. Line Contact
tips are also known as “Shibata”, providing a contact
surface between 50 and 75 μm2.
MM input
MM stands for Moving Magnet: an MM input
denotes the input stage of a preamplifier is able to
handle the signal of a Moving magnet phono cartridge
and the MM input also has an input impedance suitable
for the output impedance of MM cartridges.
Monaural
Monophonic sound reproduction (often called mono) is
single
‑channel audio program material or single channel
audio reproduction. Monaural recording on vinyl has
been replaced by stereo sound during the mid 60’s.
78rpm records and Vinyl records from 1952 to 1960 are
Monaural. Stereo sound on vinyl records was introduced
in 1958.
Moving Coil cartridges
The MC design is a tiny electromagnetic generator, but
as opposed to MM design, the 2 coils are attached to
the stylus (the moving part), and move within the field
of a fixed permanent magnet. The coils are much smaller
than MM cartridge coils and made from very thin copper
wire.
This result in a low impedance, low output signal but on
the other hand it is also very lightweight allowing for a
better response and a more detailed reproduction.
Moving coil cartridges are extremely small precision
devices and as a consequence they are considerably
more expensive, but are preferred by audiophiles due to
measurable and subjectively better performance.
Moving Magnet cartridges
The MM design is a tiny electromagnetic generator, but
as opposed to the MC (moving coil) design the stylus
cantilever carries a pair of small permanent magnets.
Those magnets are positioned between two sets of fixed
coils forming the tiny electromagnetic generator.
As the magnet vibrates in response to the stylus following
the record groove, it induces a tiny current in the coils.
Mu-metal (shielding)
Mu‑metal is a range of nickel‑iron alloys that are
notable for their high magnetic permeability. The high
permeability makes mu‑metal useful for shielding
against static or magnetic fields. Mu‑metal is frequently
used to protect low signal transformers such as the ones
found on microphone preamplifier input stages or on the
Cartridge step‑up transformers used with MC cartridges.
Several models of Audio‑Technica cartridges use Mu
‑
metal shielding between the left and right sections of
the cartridge in order to improve channel separation.
Neodymium
Neodymium is used as a component in the alloys used
to make high‑strength, powerful permanent magnets
(neodymium magnets). These magnets are widely
used throughout the audio industry in products such
as microphones, professional loudspeakers, or in‑ear
headphones, where low magnet mass or volume, and
strong magnetic fields, are required.
Nude Shank diamond
Nude
Bonded
Nude diamond refers to a stylus when the
diamond glued into the hole of the
cantilever is made out of one single piece
of diamond.
This construction as opposed to Bonded
shank (jointed) improves the mass of the
overall tip and, because the vibrating
signal does not have to transfer through
two dierent materials, provides the best
possible transient reproduction. Nude
styli, although expensive to produce, are
preferred and used on the higher priced
models.
Output Voltage (of a cartridge)
Amplitude in mV of the electrical signal delivered by
the cartridge for a given standard program material of
the record groove. Knowing the Output voltage is an
important factor: it will inform of the characteristic of
the Phono input needed in order to accommodate a given
cartridge. Output voltages may vary from under 0.1mV
for the least ecient Moving Coil models on the market,
up to 5mV for very ecient Moving Magnet cartridges.
Such dierences of more than 30dB shows that when
selecting a cartridge, the selection of the associated
preamplifier, with or without step‑up transformer, is
essential.
Overhang (Cartridge overhang adjustment)
Overhang adjustment
In the case of cartridges mounted on a removable
headshell, it could be necessary to adjust the cartridge
by several millimeters in order for the stylus to be
properly aligned with the tangent of the groove. Older
tonearms provide adjustment on their bases in order to
perform a proper setting using a tonearm protractor
alignment system. Most modern tonearms do not
provide this feature. In such a case, it is important to be
able to adapt the distance between contact point of the
stylus and axis of the tonearms with the Overhang
adjustment provided by the cartridge headshell.
Tonearm protractor
Para-toroidal coil
Para‑toroidal coils are used on high‑end Moving Magnet
Audio‑Technica cartridges, providing better channel
separation, channel balance and improved transient
response. Para‑toroidal inductors are passive electronic
components, widely used for transformer construction.
The inductor with a closed‑loop core can have a higher
magnetic field and thus higher inductance and Q factor
than similarly constructed coils with a straight core.
The advantage of the toroïdal shape is that due to its
symmetry, the amount of magnetic flux that escapes
outside of the core (leakage flux) is minimum; therefore
it radiates less electromagnetic interference to nearby
circuits or equipment.
Phono Preamp
Denotes a preamplifier with an input or a series of inputs
capable of handling the output from a Phono cartridge.
As opposed to a “standard” line input preamp such as a
Microphone input preamplifier, the Phono Preamplier will
provide the necessary gain, Input impedance matching
to the output impedance of the cartridges, and the
de‑emphasis equalisation needed to support the signal
originated from the phono cartridge playing a record.
In the case of a Vinyl record, the equalisation will usually
be RIAA.
Phono Cartridge (see Cartridge)
Phono input
Denotes the pair of input connectors (L&R) of the Phono
Preamp.
Pole Piece
The pole piece is a structure composed of material of
a high magnetic permeability that serves to direct the
magnetic field produced by the magnet. A pole piece
attaches to and, in a sense, extends a pole of the magnet,
hence the name.
Radius (stylus Radius)
The radius of a stylus is the distance (R) in either mil
(thousandth of an inch) or μm (micro, 10^‑6, of a meter).
The conical stylus has a unique Radius which varies from
0.6 to 0.7 mil for Vinyl records. (2, 2.5, 3, or 3.5mil for
shellac records). The elliptical stylus has two radii, R1
and R2, for the front and side. Standard elliptical Styli
are around 0.3 x 0.7 mil. Due to the complexity of line
contact and Microlinear styli, their radius value is not
always an accurate description of their shape and size.