I wondered if I could do that. Look for my previous thread "Can I use a Step Up Transformer with low output MM?" Here are parts of the thread:
"The problem is that you can't do that. While a transformer transforms voltage in proportion to its turns ratio, it also tranforms impedance, in proportion to the square of the turns ratio. So a 10x voltage step-up would result in the cartridge seeing a load of 470 ohms, assuming the phono stage input is 47K."
"Hey Al, if the turns ratio was 10:1, and it probably does not need to be that high to get the needed extra kick, then you could replace the 47K resistor on the secondary side of the SUT with a 4.7M one. Thus the cartridge would see 47K reflected across the SUT. But I do think their may be a problem based on the much higher inductance of the average MM/MI, vs an MC, and its interaction with the inductance of the SUT. You would know more about that than I."
"No, that wouldn't work, because the input impedance of the phono stage, presumably 47K, would be in parallel with the 4.7M resistor, resulting in an overall impedance on the secondary side of very slightly less than 47K. Two impedances in parallel result in a combined impedance equal to their product divided by their sum."
I got the impression it wouldn't sound right.