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

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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.

VPI is saying they can turn around the cartridge service with VDH in 2 weeks including shipping, which I find extraordinary

How they can ship to Netherlands back and forth withing 2 weeks in covid-19 situation when 90% of the flights canceled ? Do they really understand what they’re talking about? Mr. Van del Hul sitting there and waiting this particular cartridge to fix it for you in 24hrs or what ? Just curious. I think it’s impossible!

Even if you will ship your cartridge to SoundSmith the turn around time will be a month or so! And it's within USA.

presumably you are asking "sparate dedicated box vs built in RIAA & amplifier".
And (drum roll please) it depends on which one is better designed and executed. I happen to be working on one right now. The circuit, PCB etc will be identical whether in its own box or plugged into a motherboard. Same card. What will differ is:

• isolation (nothing like having its own box around it
• Power supply (more money can be spent due to expectations and price point)
• packaging
• price
  

Its like the integrated amp vs pre and power amp. In theory the integrated is better. In practice they are bought for the convenience, package and value, so they rarely aspire to the highest of high end.

You might infer that I’m working on one of those too. :-) In the end as noted, and i think you know this, every cartridge needs an extra 30-65 dB of gain ( and that’s a LOT) and the inverse equalization to what is done during mastering so that it is flat and accurate. No RIAA EQ, no bass. Pretty simple.
G

Dear Raul, While I yield to your generally superior experience to mine, I must say that all the information at my disposal would indicate that the 300 series of Acutex cartridges were induced magnet types.  However, the 400 series are conventional MMs.  I do see that on the Bluz Bros website, they say that BOTH series are MM, which we both know for sure is incorrect with respect to the 300 series, which makes me all the more ready to disregard anything they have to say on Acutex, especially since they have none to sell.  On the other hand, I will grant you that the 400 series LOOK a lot like the 300 series in terms of shape, which would fit the idea that the 400s are also IM types.  However, I also found this quote from a website much like this one, and surely not the last word any more than this one is the last word.  Nevertheless, "while the 420 (full name 420 STR) is a very good cartridge, it's not in the same league as the 320 (full name M320III STR). The STR refers to the "Special Tri-Radial" stylus tip, a line contact type developed by Toshiba, so the 320 and 420 have that in common but that's about it.The 420STR and M320III STR were the top of the line in their respective series but the 300 Series had things going for it that were dispensed with when the 400 Series came along. Whereas the 300 Series were an induced magnet design, the 400 Series were of the more typical moving magnet type. They also abandoned the tri-pole design which is where the magic is in these cartridges and also in the boxy "Brick" types. The stereo chain responsible for the Acutex brand of cartridges, speakers and headphones (interestingly, all transducers) was Atlantis Sound in Falls Church, VA in suburban DC."