Does it improve the sound of a MM or MI cartridge by playing it through a phono stage?

Chakster, What you say may be true for you and me, but the OP is in need of some basic understanding before getting into the nuances of a 100K ohm load vs a 47K ohm load for MM cartridges.  Right now he is fine with 47K as standard.  And I must disagree with your statement that external loading plugs are very useful for MM cartridges.  First of all because external loading plugs which in effect parallel a second resistance with whatever is the input resistance of the stage, can only lower the net resistance seen by the cartridge.  Thus, you cannot achieve 100K ohms or any value higher than 47K ohms by paralleling any value of second resistor with the standard 47K ohm load.  True, there are some who like to REDUCE the load resistance below 47K for some very particular cartridges, and this can be done by paralleling, but that is advanced thinking not needed here.  In my opinion, the capacity to add an external load resistor in parallel with the primary resistance is by far more relevant to MC phono stages than MM ones.

The settings on the phono stage are 100 ohms, 200, 1000, 10000, 47000. Not 100K. For my back up MC cartridge, if I do use it, I will select the 47K ohm setting for impedence and 50dB gain on my phono stage..

@sokogear : The Plinius impedance is set/default at 47k and you can't change it. What you can change is the Plinius phono gain.
Due that you used the VDH cartridge then that Plinius si already setted at high gain ( 0.7mv. ) that is to high for the Acutex 3.5mv output and could overload the Plinius and if this happens you will have higher distortions. 
So, if you want to use the Plinius you need to set up its gain to 1.5 low gain.

"  Would the Sutherland at 47K ohms sound any better than the Plinius' phono stage? Does it matter if it is a MC or MM/MI cartridge? "

No one but you can answer the first question after test it both units with the Acutex cartridge.
 Not only Plinius and Sutherland are different electronic designs but to use the Sutherland you need too additional IC cables that means not only additional cables/wires where the cartridge must travel and where exist some kind of degradation but exist additional input/output RCA connectors and solder joints that make degradation to the signal too.

To the second question: its matters only for the gain and loading need it for either kind of cartridge.


""   Will the Sutherland's 47K ohm setting sound similar?  ""

No, both units are different electronics designs and with different builded active/passive parts and even circuit boards material.


"""  I was thinking with a standard output MM cartridge, it wouldn't matter what phono stage you used as long as it operated or had a setting at 47K ohms. """

It would matters. Again different electronic designs tend to sounds different. Your way of thinking makes no sense at all.

Btw, your 412 is an induced magnet design not a MM one.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Chakster, What you say may be true for you and me, but the OP is in need of some basic understanding before getting into the nuances of a 100K ohm load vs a 47K ohm load for MM cartridges. Right now he is fine with 47K as standard. And I must disagree with your statement that external loading plugs are very useful for MM cartridges. First of all because external loading plugs which in effect parallel a second resistance with whatever is the input resistance of the stage, can only lower the net resistance seen by the cartridge. Thus, you cannot achieve 100K ohms or any value higher than 47K ohms by paralleling any value of second resistor with the standard 47K ohm load. True, there are some who like to REDUCE the load resistance below 47K for some very particular cartridges, and this can be done by paralleling, but that is advanced thinking not needed here. In my opinion, the capacity to add an external load resistor in parallel with the primary resistance is by far more relevant to MC phono stages than MM ones

.
Right, that's why internal input resistors in my JLTi phono stage are 500k Ohm (special mod i asked for), so i can use parallel 100k RCA plug for my MM.  

I think the Sutherland will sound better either way because it sounded WAY better with the Van den hul. I would have to switch it to low gain, but if I do this I would probably just use the Sutherland with the 47K load and 45dB gain.

In all likelihood, I will live without any fiddling around with the cartridge as VPI is saying they can turn around the cartridge service with VDH in 2 weeks including shipping, which I find extraordinary, but if it is specifically scheduled, I guess it is possible.