My needles have got rusty babe
They will not play at all
Now we played it on the sofa
We played it side the wall
My needles have got rusty
And it will not play at all
– Robert Johnson
So just what are ya gonna stick on the end of that $35,000 tone arm you bought?
Phono cartridges. Been around in some form since 1925. Known in common circles as a ‘pickup’. Decidedly different than your Ford F-150, and from what you try and do at the bar on a Friday night.
For something so small there is a lot that goes into them. Basically what a pickup is, is an electromechanical transducer. The cartridge assembly comprises a number of components including: a stylus, cantilever, magnets, coils, a body or housing, and wiring and whatnot.
Back to the truck analogy… the stylus is where the rubber meets the road. It is the part that is the interface with the record surface and tracks the modulations in the record groove. Usually made from a polished diamond or other gemstone such as sapphire. The cantilever part supports the stylus, and in turn transmits the vibrations from the stylus to the coils / magnets. Cantilevers are also sometimes constructed of exotic materials like boron or beryllium.
Finally, coupled to the tonearm, the cartridge body’s function is to give the moving parts a stationary platform so that they can track the groove with precision
As far as the electronics go there are two basic types and a couple of variations of design.
Moving Magnet or MM. In this type the cantilever carries a small permanent magnet that is positioned between two sets of fixed coils, thus forming a small electromagnetic generator. The magnet vibrates in response to the stylus following the groove in the record; in doing so it creates an electric current in the coils which is then in turn fed to signal processing equipment in the various off-board amplifiers.
Moving Coil or MC. This design is also a tiny electromagnetic generator, but with the magnet and coils reversed from the MM design. Meaning that the coils are attached to the cantilever, and move within the field of the permanent magnet. The coils are small and made from extremely fine wire. Because the number of windings is so small the resulting output voltage is small as well; in the range of a few hundred micro volts. This requires speciality pre-amplifiers or step-up transformers.
So which should I get you ask?
Moving coil cartridges are extremely small precision instruments and are therefore generally quite expensive, but are frequently preferred by audiophiles due to a subjectively better performance. They have very low impedance and inductance, therefore effects of cable capacitance are not an issue, like it is in MM designs. This certainly gives the sonic advantage to MC. Typically MC also usually offer lower moving masses; thus providing another advantage. Although there are some very low mass MM cartridges as well that rival or even exceed the mass of an MC. In general terms MC are considered higher end products by stereophiles although there are some very good if not downright comparable MM cartridges out there.
And it may be that stylus and cantilever design have a more significant influence on sound than whatever differences occur because of MM vs MC. The other thing one has to keep in mind is that there are different signal amplification requirements for each, which means that you need the correct pre-amp for the cartridge you have. I will cover that in another story.
That being said here is a small selection of ones to choose from:
For you budget conscious folks out there, this might be the cartridge for you.
Features: Ebony Wood Body | Aluminum Cantilever | Total Mass 8.8gm | Frequency Response 20Hz to 20kHz | Channel Separation 26dB | Compliance 15 µ/mN
For a nice middle of the road option the MC Ortofon Anna Diamond might be just what you are looking for.
Features: Titanium Body | Boron Cantilever | Diamond Stylus | Total Mass 16gm | Frequency Response 20 Hz – 20 kHz +/- 1.5dB | Channel Separation 25 dB | Compliance 9 µ/ mN
For the less budget conscious there is this little piece of MC jewelry
Features: Twelve magnets arranged in a patented ring configuration | Generator coils are wound using pure 24-karat gold wire | Body machined fro 14-karat gold providing excellence resonance damping | EMF Shielding of the generator assembly | Boron Cantilever | Diamond Stylus | Total Mass 15gm | Frequency Response 20hz – 20kHz | Channel Separation >32 dB | Compliance 15µ /mN | Plus the added bling of a 1/2-karat diamond mounted on the front of the body
Of course you could always get one of each and mount them on the three separate tonearms you put on that Goldmund Reference Turntable…
One time in San Francisco
I was standin’ in an airport line
In one bag I had all my clothes and in the other was all them ol’ records of mine
The lady said I could only bring one bag
I had two, Oh what a drag
I had to jump on the plane and leave all my clothes behind
– Todd Snider