The needles on your record players are a small part of a small part of a system. But as the very first part of the chain, a mistake here ripples through the entire chain. So they are (very arguably) the most important in the whole chain.
Sources of Info:
The stylus tip is the part of the record playing cartridge that actually sits inside the records grooves. Therefore it is the part of the system that physically retrieves the information from the record’s surface. This stylus tip is designed to last hundreds of hours, so they are typically made from specially cut diamonds.
Stylus Profile Types:
Pinching isn't cute – The Spherical or Conical Tip
If you are looking from the top down into the groove, the cross-section of the stylus tip that is actually within the groove is a circle, as shown in the diagram below (Compared to a cutting lathe stylus profile):
As you can see in the pinch effect diagram, the circular cross section has to decrease where the slope is steepest (Highest tangential acceleration) This means the the stylus actually has to move vertically (up and down) This creates a strong distortion in the high frequency signal.
This is one of the main reasons why spherical styli sound significantly worse than many of the alternatives.
Curves are... The Elliptical Stylus
The elliptical stylus was designed to solve the problem of pinch effect distortion. The diamond tip is cut in a slightly more elaborate fashion in order to mimic more closely the profile of a typical record cutting lathe’s.
Due to the fact that the elliptical stylus fits much closer to the grooves of the record, they extract a bunch more detail (particularly in the high frequencies) than the equivalent spherical tipped styli.
A wide variety of the most affordable hi-fi cartridges use elliptical tipped stylus because they can sound great even in relatively cheap designs.
The other advantage of the elliptical tip stylus is that because the tracking force is more evenly distributed over the record grooves, there is should be less wear on the record and the stylus itself.
Popular Examples of Elliptical Tipped Styli:
Not all ellipticals are created equal!
As you can see there is quite a variation in pricing between the available elliptical models. There are a number of factors in the cartridge generator itself, but another is whether the diamond is "Bonded" or "Nude"
Basically thee bonded type have a small metal point which sticks out from the cantilever, where the nude is directly mounted into the cantilever. This allows the Nude type to typically have a much smaller moving mass and typically sound much better. They are also much more expensive to produce.
An excellent example of a nude Elliptical Stylus is the Ortofon 2M Blue
Line Contact Shapes – Shibata, Fritz Geiger, Hyper Elliptical etc.
One of the major issues with the standard elliptical shaped tip, is that it makes contact with quite a narrow vertical range of the groove walls. The wear over the record grooves walls is therefore concentrated over a very narrow vertical range, which then gets played back. This means that the worn part of the record is always played.
The Shibata tip was initially developed for use in early quadraphonic systems, which used signals right up to 40kHz. The Shibata’s (and other similar Line Contact Profiles) superior high frequency tracking made it perfect for this task, but also make it perfect for retrieving any high frequency details recorded in the audible range (<20,000Hz)
These sorts of tip profiles also have excellent contact area (as can be seen in the diagram above) which means the wear on the record and stylus tip is minimised.
All of these different line contact types use the same principle, and some can vary very little from each other. The downside to these types of styli are that for perfect operation, the verticle angle of your tone-arm must be perfect. Your tone-arm must have VTA adjustment to get the most out of this type of cartridge.
Excellent examples of these kinds of Cartridges include:
Summing it up
Even this one little element of one little element of your stereo system can be very complicated! The guys and girls in both of our stores are very conversant in the differences and can help translate some of this into plain English. Be sure to get in contact if you have any questions or would like to know more.