Dear @newtoncr : Well I think that you have the Anna diamond Ortofon recomendation that's higher than 10ohm and the cartridge it self is not sensitive ( as any LOMC cartridge ) to impedance changes if sounds different changing the impedance then that " problem " comes by the phono stage design.
A SUT goes totally against the Ortofon or any other LOMC and you don't need that instead the direct CH high gain stage be changed not only for the SUT but those additional input/output/solder joints and IC cables where the cartridge signal mus pass through and don't forget the SUT internal construction/wire.
If I was you I just forgeret about the SUT. Obviously is up to you but there is no active/sut combination that can outperforms your CH active high gain stage.
R.