I went from knowing nothing to learning here, then researching ... for myself and friends.

I made a virtual system with copies of SUT pages I have gathered

you will need to increase your screen’s zoom to read some charts

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**SUT indications can be quite confusing**, i.e.

my Fidelity Research FRT-4, in round numbers:

setting 3 ohms is x Factor 36. (+31 db)

setting 10 ohms is x factor 21 (+26db) (possibly what your #10 is referring to?)

setting 30 ohms is x factor 18 (+25db)

setting 100 ohms is x factor 11 (+20db)

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a borderline low signal strength needs to be** checked against your preamp’s mm phono sensitivity**, i.e. my mx110z preamp's phono sensitivity is 3.0 mv. thus the calculated 3.2mv above would not be my choice.