You didn't mention your cartridge. Basically MM cartridges are all loaded at 47Kohm so no problem there --- one size fits all. But they are sensitive to capacitance, which is additive. The manufacturer of MM cartridges lists the proper capacitance loading in the specs. So you have to know the capacitance of your tonearm cable (the one between the tonearm and the phono preamp) in pico-farads/foot (times its length in feet) plus the default capacitance in the phono preamp section. Usually, unless your cables are very long (not recommended over 3 feet anyway) you'll need to add a little capacitance to the phono preamp in the form of small capacitors soldered across the inputs -- usually there's a place for loading resistors and/or capacitors provided on the circuit boards or elsewhere in the preamp.
MC cartridges are the reverse. They're not affected much by capacitance, but are critical to loading resistance. 47Kohm will never do for the (comparitavely) lower output MCs. It's way too much. A good rule of thumb (i.e. place to start) is 25 times the coil resistance of the cartridge. That generally winds up somewhere between 100 - 1000 ohms. Then you can vary it up or down 50% (from the 25 times number) until you get the best results.
MC cartridge loading is covered quite extensively elsewhere in these forums.
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MC cartridges are the reverse. They're not affected much by capacitance, but are critical to loading resistance. 47Kohm will never do for the (comparitavely) lower output MCs. It's way too much. A good rule of thumb (i.e. place to start) is 25 times the coil resistance of the cartridge. That generally winds up somewhere between 100 - 1000 ohms. Then you can vary it up or down 50% (from the 25 times number) until you get the best results.
MC cartridge loading is covered quite extensively elsewhere in these forums.
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