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Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

RE: unfairly roughed up

> They state unequivocally, a phase shift approaching 180° occurs at mechanical resonance.

I am not arguing against the occurrence of a mechanical resonance from cantilever elasticity and effective tip mass, but there is also an electrical resonance in all circuits containing an inductor and a capacitor. Consequently, all cartridges have an electrical resonance in addition to their mechanical cantilever resonance.

The cartridge electrical resonance is a result of the inductance of the cartridge's coils reacting with the capacitance of electrical wiring combined with added capacitive loading. In other words, all cartridges exhibit an electrical resonance when connected to a phono stage and this always results in phase reversal. The values of inductance associated with high-output moving magnet cartridges places their electrical resonance in the upper audio octave between 10-kHz and 20-kHz whereas the same electrical resonance for all low-output moving coils is always above 1-MHz, well outside the audio frequency range.

Therefore, not only do cartridge designers have to contend with the mechanical resonance of the cantilever, but they also have to contend with an electrical resonance being smack dab in the middle of the upper audible octave for MM cartridges only. They do not have to worry about the electrical resonance for low-output moving coils because it occurs above 1-MHz.

The reason original Dynavector cartridges were made with very short, fat ruby and diamond cantilevers was to move their cantilever bending resonances as far above the audible frequency range as possible. Most ordinary cartridges have their cantilever mechanical resonance right around 20-kHz or slightly above, but Dynavector made cartridges with mechanical cantilever resonances at 50-kHz and beyond. In fact, the 17D has its cantilever bending resonance at 80-kHz and the old 13D with its 1.3-mm short diamond cantilever had its cantilever bending resonance at 100-kHz. These cartridges had both their mechanical and electrical resonances so far removed from the audible frequency range that they didn't have to contend with any phase shift within audible frequencies.


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