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MC vs MM

Discussion in 'Audio Hardware' started by Holy Zoo, Jan 28, 2002.

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  1. Kevin Sypolt

    Kevin Sypolt Forum Resident

    Rocklin, CA
    Thanks Mazort! It's definitely all about the music (and great tone)...
  2. mazort

    mazort New Member

    San Antone
    The world according to Grado




    It would be impossible to describe the Grado Statement series without first discussing the virtues and shortcomings of the moving coil cartridge design. The Statement series is a hybrid, which incorporates the best aspects of the moving coil pickup with the best aspects of the Grado flux-bridger design.

    The mechanical generator system of the moving coil cartridge has its limitations. The copper wire wound on the heavy iron armature creates a large torsional mass, resulting in the generator motion disturbing the stylus and groove contact accuracy. This is heard as the characteristic moving coil sound, which is hard and edgy. It is quite possible to selectively alter this resonant color to "enhance" the sound, but no matter what, it is still distortion.

    The outstanding quality of the moving coil cartridge is not the moving coil principle but the very low DC resistance and inductance. When the electrical impedance of a cartridge rises within the frequency response of the hearing range, the preamplifier generates audible distortion. This occurs because the preamplifier is valiantly trying to match the varying impedance and not quite succeeding.

    Due to its low DC resistance, the moving coil cartridge presents a constant electrical impedance to the preamplifier at all frequencies, this results in a very low electrical distortion. This is the beauty of the moving coil: the constant electrical impedance makes the cartridge sound good despite the limited quality of the mechanical system.

    The distortion that is caused by a slight rising impedance in the Grado cartridges is more than offset by their superb mechanical system. Unlike other moving iron cartridges that have one random distorted magnetic gap, all Grado cartridges have four separate magnetic gaps, each gap having exactly the same pure configuration as the gap in a moving coil cartridge.

    In Grado cartridges a cantilever positioned in the longitudinal center between the four gaps carries a piece of very sophisticated iron (with absolutely no residual buildup properties). The swinging cantilever moves the iron into the magnetic gap, shunting the gap and increasing the amount of magnetic flux within the gap. The iron, acting as a fluxbridger, leaves the flux path in the gap undistorted. The result is very low playback distortion.

    In the moving coil cartridge design, the tilting motion of the iron armature causes it to act as a flux relay device, thereby creating a large amount of flux path distortion. The end result is a "spitty" sound.

    Due to the extremely high power factor in the Grado fluxbridger design, it is possible to design a new series of cartridges with a constant electrical impedance exactly like that of a moving coil.

    The torsional mass characteristics of the Grado cartridges have always been superior to that of the moving coils. The frequency of the torsional resonance in a moving coil usually occurs between 6-10 kHz, depending upon the quality of the particular cartridge. The higher the moving coil output, the more irritating the torsional distortion.

    The torsional resonance of the new "hybrid" (the best part of the moving coil concept and the best of Grado's design) occurs at approximately 30 kHz, well beyond audibility. One must realize that the more torsional resonance that can be heard, the more colored and distorted the sound becomes.

    Grado is introducing four new models of phono cartridges. These new models will be an expansion of the Statement Series. They will duplicate the Reference Series in model names, i.e., Reference Platinum, Statement Platinum; Reference Sonata (Signature), Statement Sonata (Signature); Reference Master, Statement Master and Reference Reference, Statement Reference. Price points will be the same for both corresponding models. We will not be discontinuing the Reference series, but will offer both series of cartridges.

    The Reference series will be the high output cartridges (5.0 mV) while the Statement series will be the low output versions (0.5 mV).

    There are physical differences between the Reference cartridges and the new Statement cartridges. Each Grado cartridge has four coils. The Reference series cartridges have a total of 6,000 turns of wire on the coils. The Statement series has a total of 380 turns. Since we have considerably fewer turns in the Statement series, we can use a much larger size wire. This new wire has over 16 times more area for carrying the signal; it also lowers the resistance from 470 ohms in the Reference series to 2 ohms in the Statement series. Fewer turns of wire on the coils shortens the distance the signal must travel from 125 feet to a little more than 7 feet. In the Statement series we have also shortened the magnetic generating gap in the stylus, increasing the flux density.

    What will be heard from these differences? The new Statement series will have a sound that is wide open, uncolored, with better definition and transparency and increased dynamics. The Statement series offers enhanced tracking with improved imaging and more musical information. All of this, along with Grado's usual warm, smooth, full bodied, non-fatiguing and rich sound qualities.

    If your system can be driven with a 0.5 mV output phono cartridge, then you deserve to be listening to the new Grado Statement Series.
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