Best loadings for Shelter 501 Mkll


Hi All,
First a disclaimer; I have virtually no understanding of what resistive and capacitave loads are. However, I am hoping to improve the already excellent sound I am getting from this cartridge as played through my highly adjustable Jon Soderberg modified Threshold FET9 pre amp.
The big problem with this pre is that to change the settings it must be removed from the rack, the top cover removed and jumpers shifted. Not terrible, but not the flick of a switch either.
I currently have it set to 47Kohms, 50pf (whatever that means!) but wonder if anyone knows from practical experience what would sound best. I can select from 47K or 100, 47, 32 Ohms and 50, 100, 200 or 250 picofarads.
The Threshold manual implies that there will not be a big difference in sound for MC cartridgesby stating,"as a group, moving coil cartridges are relatively insensitive to their capacative load".
Given the lack of easy adjustability I would like to get it right the first shot, so knowledgable inputs would be greatly appreciated.
Thanks in advance!
drjay
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