Moving coil cartridges do indeed have the lowest inductance of any of the three types, by far, but they also have the highest moving mass. Moving iron type cartridges have the lowest moving mass on average. MM types are somewhere in between. Therefore, any response retarding effect due to hysteresis caused by inductance is compensated for by very low moving mass in the case of the moving iron cartridge. Which may explain why the general conclusion that MC cartridges exhibit superior high end clarity, based on hysteresis alone, does not conform to my long-term observations of the performance of the three types of cartridge.
MM or MI Cartridge?
Currently using an SPU Royal N with a Viv Labs 9" and Kuzma Stabi R, and I am looking for a great Moving Magnet or Moving Iron Cartridge that I won't feel short changed by.
A couple of options I am looking at are the Grado Reference "The Reference" Wood 2 and the Audio Note IQ3, has anyone had the opportunity to compare these cartridges, and any other options I should consider that you have heard against either of these cartridges?
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Well said, @lewm . |
Bunch of ill thought out hooey here! Hysteresis refers to the coil core material ONLY. There is no hysteresis in an air core coil, or a non-magnetic core material, such as aluminum or plastic. Iron alloy *can* have hysteresis, depending on the alloy or physical form. Hysteresis results in loss of magnetic flux, but no loss in speed, as magnetic flux is transferred at the same speed of light as do electrons travel through a conductor. Resistance to electrical flow or magnetic flux may decrease energy transfer, but NEVER speed! You need to go back and study EE 101! Laminated coil core materials exhibit very little hysteresis, as used in the Shure M24, V15-III, IV, V. MI cartridges, as a subset of MM, have wide ranging inductances, as do MM carts. There is no “set” range of inductances just because a cart is MI, or MM. To say there is, displays a complete ignorance of cartridge types and design over the last 7 decades. Inductance of MM/MI carts determines output using a given magnetic flux density. Cartridge loading affects FR of a given combination of inductance and magnetic field strength. MC, or MI/MM just categorizes which comprises you choose to accept. There is no inherent superiority. Whichever you choose, choose wisely. There are so-so MC carts, and also MI and MM carts. Don’t use a broad brush, using a bad example of an MC to condemn MCs, or condemn all MMs or MI carts because you had a so-so example. |
Wolfie, Good point about the relationship between hysteresis and core material, or lack of same. But to my observation, the three types do group well apart from each other if you base it on inductance. LOMCs are always much less than 100uH (micro-Henries). Many are actually down in the 10uH and below range. Whereas MI types typically measure in the low mH range, and a classic MM will measure 400mH and higher. The difference between 10uH (for a LOMC with low internal R) and 500mH (for a classic MM) is 50,000X! But I still stand by my reasoning (see above) and my listening experience that leads me to believe the difference in inductance does not make LOMCs inherently superior to MI and MM types. So, you and I agree on the end point. |
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