Over a decade ago I made the below linked post and still stand by it 100% today.
https://forum.audiogon.com/discussions/thoughts-on-cartridge-loading-with-a-sut?highlight=intractaudiohttp://
Some basic takeaways I have found.
-Loading the secondary is the worst thing you can do to a transformer. With a known source / load combo an optimal transformer can be designed.
-47K is a silly value for the input of a phono stage when considering a SUT. Selecting a turns ratio on the reflected load of that 47K is misguided.
-Turns ratio and cartridge load should have zero connection to each other when selecting a SUT. Turns ratio should be set for appropriate gain (with careful attention to possible overload). Load resistor should be also as high as possible. Any needed cartridge load should be placed directly at the cartridge.
-Zobel Networks are a Band-Aid for a source to load mismatch of a transformer. They will make the test equipment happy but always leave the music feeling something is amiss.
-high Q resonant behavior of a SUT at 30Khz is audible and objectionable yet Low Q resonant behavior above 100Khz seems audibly benign.
dave
https://forum.audiogon.com/discussions/thoughts-on-cartridge-loading-with-a-sut?highlight=intractaudiohttp://
Some basic takeaways I have found.
-Loading the secondary is the worst thing you can do to a transformer. With a known source / load combo an optimal transformer can be designed.
-47K is a silly value for the input of a phono stage when considering a SUT. Selecting a turns ratio on the reflected load of that 47K is misguided.
-Turns ratio and cartridge load should have zero connection to each other when selecting a SUT. Turns ratio should be set for appropriate gain (with careful attention to possible overload). Load resistor should be also as high as possible. Any needed cartridge load should be placed directly at the cartridge.
-Zobel Networks are a Band-Aid for a source to load mismatch of a transformer. They will make the test equipment happy but always leave the music feeling something is amiss.
-high Q resonant behavior of a SUT at 30Khz is audible and objectionable yet Low Q resonant behavior above 100Khz seems audibly benign.
dave