He hasn't solved his problem, although he now knows why the SUT did not work ( there was a 100ohm loading resistor already in the SP14 ), I believe the last post I saw was that he still had hum issues.
He is not using a current injection stage.
Apparently he is going back to loading at the tonearm 25ohms, which means that given there is already a 100ohm loading resistor in his SP14 that he is effectively loading his 12ohm cartridge at 20ohms. If you think this is a good idea - good luck to you.
I really don't care what the OP does - but for those who are more open minded, I have set up plenty of OC9's over the years - in most instances where customers were using solid state phonos ( excluding current mode ) I found optimum loading usually around 400-470ohms.
Do you not think the cartridge designer and manufacturer knows what they are doing when they recommend a minimum of 100ohms ?