Please provide an explanation of stylus shapes and terms.
The typical Shure spherical stylus tip has a radius of 0.7 mil.
• Positive attribute: less tip wear due to a larger surface area contacting the record.
• Negative attribute: high frequency response will be rolled-off as the "large" radius of the tip will not trace the "small" grooves containing the highest frequencies.
The typical Shure biradial stylus tip has radii of 0.4 x 0.7 mil or 0.2 x 0.7 mil.
Note: The term "biradial" describes the stylus tip shape more accurately than the more commonly used term "elliptical".
• Positive attribute: better high frequency response than a spherical due to the smaller contact radii of the stylus tip.
• Negative attribute: slightly faster tip wear than a spherical due to the decreased tip/groove contact area.
See Biradial above.
• Positive attribute: longer tip life than a biradial.
• Negative attribute: difficult to manufacture and therefore expensive.
If a cartridge requires a hyperelliptical stylus tip (a tip shape no longer offered by Shure), substitute a biradial stylus with 0.2 x 0.7 mil tip.
The Micro-Ridge is the most advanced tip shape available. It is based on a hyperelliptical design but has additional shaping to the tip to create the "Micro-Ridge".
• Positive attribute: lowest tip wear of any tip shape AND the best high frequency response.
• Negative attribute: very difficult to manufacture and therefore very expensive.
Stylus for 78 RPM records
The groove of a 78 RPM record is much wider than the groove of a 33 1/3 RPM record, so a larger stylus tip is required. The tip radius should be 2.0 mils or larger. The tip shape should be spherical.
• If a 0.7 mil spherical stylus tip is employed, it will ride very low in the groove and may even ride on the bottom of the groove. This portion of the groove will likely be rough and dirty, resulting in a very noisy signal.