I've been living with a 501-II for several years.
Be that is it may, the mfr recommends 100 ohms.
Btw, basic rule of thumb for MC loading: internal resistance X 10. The Shelter's internal resistance is 10 ohms. So by this rule 100 ohms would be the first choice.
However many different people have reported using this cart at various loadings as high as 1000 ohms and being happy. It is probably system dependent for those individuals.
I've tried mine at 470 ohms and was happy. I've tried it at 209 ohms and am happy. Not much difference between those two settings. Same essential character. Same frequency extension top to bottom. Same tone color.
But then I'm not using a stage with multiple settings. I can't just turn a switch to try a different setting. Nor can I move a dip switch under the lid.
Rather, I use different step up transformers to alter gain and load. My current step-up is 1:15 turns ratio. It multiplies cart output voltage times 15 and then alters load as follows:
47K / turns ratio squared. or 47k / 15². It works out to 208.8 ohms.
That seems to be a happy place for the Shelter. In order to reach 100 ohms I would need to use a turns ratio of 1: 20. But then the cart output voltage gets multiplied x 20 and that would be too high for the input side of most mm phono stages (14mv). So, in my situation, resistor tuning is needed to fine tune the load any closer to that 100 ohm goal. See how easy you've got it...;-)
In any case, the real determining factor should be your ears and listening preference. Given your options I'd choose the setting closest to 100 ohms and listen a while. But you can try the other settings without fear of harm.
-Steve
Be that is it may, the mfr recommends 100 ohms.
Btw, basic rule of thumb for MC loading: internal resistance X 10. The Shelter's internal resistance is 10 ohms. So by this rule 100 ohms would be the first choice.
However many different people have reported using this cart at various loadings as high as 1000 ohms and being happy. It is probably system dependent for those individuals.
I've tried mine at 470 ohms and was happy. I've tried it at 209 ohms and am happy. Not much difference between those two settings. Same essential character. Same frequency extension top to bottom. Same tone color.
But then I'm not using a stage with multiple settings. I can't just turn a switch to try a different setting. Nor can I move a dip switch under the lid.
Rather, I use different step up transformers to alter gain and load. My current step-up is 1:15 turns ratio. It multiplies cart output voltage times 15 and then alters load as follows:
47K / turns ratio squared. or 47k / 15². It works out to 208.8 ohms.
That seems to be a happy place for the Shelter. In order to reach 100 ohms I would need to use a turns ratio of 1: 20. But then the cart output voltage gets multiplied x 20 and that would be too high for the input side of most mm phono stages (14mv). So, in my situation, resistor tuning is needed to fine tune the load any closer to that 100 ohm goal. See how easy you've got it...;-)
In any case, the real determining factor should be your ears and listening preference. Given your options I'd choose the setting closest to 100 ohms and listen a while. But you can try the other settings without fear of harm.
-Steve