Many of the above posts are incorrect.
The reason why loading has an effect has nothing to do with the cartridge directly. It has to do with the stability of the preamp.
The inductance of the winding of the cartridge is in parallel with the capacitance of the tone arm cable. This forms a Radio Frequency tuned circuit (also known as a tank circuit). The tank circuit is set into oscillation by the energy produced by the cartridge. It often resonates at several MHz and thus produces RFI (Radio Frequency Interference). Some preamps don't like that and don't sound right as a result.
The loading resistor detunes the tank circuit enough that it will no longer resonate. Then the preamp sounds fine.
If however, the preamp is properly designed and is stable with RFI, then the loading resistor will be found to have no effect.
IOW, if you need the loading resistor to make your cartridge sound right, it points to a stability problem in the preamp.
You can find this topic discussed elsewhere on this site and others. Jonathan Carr of Lyra and Jim Hagerman have discussed it at length as well as myself. Jim has a good article online:
http://www.hagtech.com/loading.html
-which goes into the math of it.
Our preamps are stable so no loading is needed. We provide a loading strip, but it is mostly for high output MM cartridges where loading is critical and affects the cartridge directly at audio frequencies.
One additional point- when loading the cartridge, you are making it do work. This stiffens up the cantilever, changing its tracking characteristic- it will be less compliant; that's not a good thing. You are better off with a stable phono preamp.
The reason why loading has an effect has nothing to do with the cartridge directly. It has to do with the stability of the preamp.
The inductance of the winding of the cartridge is in parallel with the capacitance of the tone arm cable. This forms a Radio Frequency tuned circuit (also known as a tank circuit). The tank circuit is set into oscillation by the energy produced by the cartridge. It often resonates at several MHz and thus produces RFI (Radio Frequency Interference). Some preamps don't like that and don't sound right as a result.
The loading resistor detunes the tank circuit enough that it will no longer resonate. Then the preamp sounds fine.
If however, the preamp is properly designed and is stable with RFI, then the loading resistor will be found to have no effect.
IOW, if you need the loading resistor to make your cartridge sound right, it points to a stability problem in the preamp.
You can find this topic discussed elsewhere on this site and others. Jonathan Carr of Lyra and Jim Hagerman have discussed it at length as well as myself. Jim has a good article online:
http://www.hagtech.com/loading.html
-which goes into the math of it.
Our preamps are stable so no loading is needed. We provide a loading strip, but it is mostly for high output MM cartridges where loading is critical and affects the cartridge directly at audio frequencies.
One additional point- when loading the cartridge, you are making it do work. This stiffens up the cantilever, changing its tracking characteristic- it will be less compliant; that's not a good thing. You are better off with a stable phono preamp.