Hi Don:
Among cartridge manufacturers, "micro line" is used only to refer to the microline and microridge styli manufactured by Namiki Jewel. Among audiophiles, however, it appears to be used more broadly to designate advanced line-contact styli in general, which is wrong and a source of confusion.
The major hallmark of the microridge profile is that contact with the LP groove is achieved by side wings or ridges that protrude to either side of the stylus. If you could look at a microridge from directly above with a microscope, you would see that these ridges stand proud of the main section of the stylus, and have a very narrow side radius of 2.5um. Due to the small side radius, the microridge has better high-frequency capabilities than any other stylus shape, and due to the protruding nature of the ridges, the microridge can be worn perceptibly and still retain its high-frequency tracking capabilities. With other stylus profiles, wear causes the side radii to become bigger and bigger, and this means that the high-frequency tracking capabilities deteriorate.
However, there is more to a stylus than just the side radius. If you look at a line-contact stylus from the front, you will see that it is shaped like a spearhead with curved (convex) blades. This curvature is referred to as the major radius, and the shape and size determines the vertical length of the stylus' contact patch with the LP groove. The larger the major radius, the longer the contact patch becomes, but alignment becomes less tolerant of errors.
The the Ogura PA has major radius of 30~35um, the microridges have a major radius of about 70~75um, while stylii like the Replicant 120 and Gyger S will have a major radius of about 120um. As you can surmise, the microridges can track more of the groove than a PA, and a Gyger S can track even more of the groove (but will be trickier to set up).
OTOH, the Replicant 120 and Gyger S have a side radius of around 5~6um, about double that of the microridge. FWIW, the Ogura PA has about 3um. A larger side radius is kinder if you are playing records made of fragile materials (like molded styrene), but the larger side radius will fit less well into very high frequency groove undulations, which get smaller the shorter the signal wavelength (IOW, the higher the frequency).
In summary, rather than what is better or worse, these stylus profiles were designed with different philosophies and priorities, and different styli may be preferred depending on what the cartridge designer wants to achieve for a specific model.
The longer major radius of the Gyger S suggests that you will need to be more careful of azimuth during setup, while the microridge won't be quite so demanding in this respect (but more so than with a PA). Molded styrene records may be OK with the Gyger S, but should be kept away away from cartridges with microridge or PA styli.
regards and hth, jonathan carr (lyra cartridge designer)
Among cartridge manufacturers, "micro line" is used only to refer to the microline and microridge styli manufactured by Namiki Jewel. Among audiophiles, however, it appears to be used more broadly to designate advanced line-contact styli in general, which is wrong and a source of confusion.
The major hallmark of the microridge profile is that contact with the LP groove is achieved by side wings or ridges that protrude to either side of the stylus. If you could look at a microridge from directly above with a microscope, you would see that these ridges stand proud of the main section of the stylus, and have a very narrow side radius of 2.5um. Due to the small side radius, the microridge has better high-frequency capabilities than any other stylus shape, and due to the protruding nature of the ridges, the microridge can be worn perceptibly and still retain its high-frequency tracking capabilities. With other stylus profiles, wear causes the side radii to become bigger and bigger, and this means that the high-frequency tracking capabilities deteriorate.
However, there is more to a stylus than just the side radius. If you look at a line-contact stylus from the front, you will see that it is shaped like a spearhead with curved (convex) blades. This curvature is referred to as the major radius, and the shape and size determines the vertical length of the stylus' contact patch with the LP groove. The larger the major radius, the longer the contact patch becomes, but alignment becomes less tolerant of errors.
The the Ogura PA has major radius of 30~35um, the microridges have a major radius of about 70~75um, while stylii like the Replicant 120 and Gyger S will have a major radius of about 120um. As you can surmise, the microridges can track more of the groove than a PA, and a Gyger S can track even more of the groove (but will be trickier to set up).
OTOH, the Replicant 120 and Gyger S have a side radius of around 5~6um, about double that of the microridge. FWIW, the Ogura PA has about 3um. A larger side radius is kinder if you are playing records made of fragile materials (like molded styrene), but the larger side radius will fit less well into very high frequency groove undulations, which get smaller the shorter the signal wavelength (IOW, the higher the frequency).
In summary, rather than what is better or worse, these stylus profiles were designed with different philosophies and priorities, and different styli may be preferred depending on what the cartridge designer wants to achieve for a specific model.
The longer major radius of the Gyger S suggests that you will need to be more careful of azimuth during setup, while the microridge won't be quite so demanding in this respect (but more so than with a PA). Molded styrene records may be OK with the Gyger S, but should be kept away away from cartridges with microridge or PA styli.
regards and hth, jonathan carr (lyra cartridge designer)
