repeat

AN-S4/L  - 3 Ohm input impedance - Primarily designed for use with the Audio Note (UK) IO range

note that 0.75 x 4 = 3

AN-S4/LM - 12 Ohm input impedance - For cartridges with an impedance of 3 to 4 Ohms

note that 3 x 4 = 12

AN-S4/M - 27.5 Ohm input impedance - For cartridges with an impedance of 7 to 9 Ohms

note that 7 x 4 = 28

AN-S4/H - 48 Ohm input impedance - For cartridges with an impedance of 12 to 16 Ohms

note 12 x 4 = 48

so, their input designations are 4x the lowest coil impedance, WTF?????

Like I said before, a transformer has no impedance by itself, except for the resistance of the primary. You need to know what it is hooked up to on the secondaries, which one might assume is 47K ohms for a SUT. The resistance of the primary with no load, so far as I know, would typically be in the one ohm-ish range.  I never measured a SUT, but I have measured the primary resistance of a few power transformers. Anyway, those numbers (3, 12, 27.5, and 48) are unlikely to represent the resistance across the primary.  Maybe Intact would comment.

That's why I calculated the turns ratio based on the idea of the SUT hooked up to 47K ohms so that the cartridge sees 27.5 ohms.  If you do the math, you get a turns ratio of 1:40-ish. I doubt that is correct. For vintage Japanese SUTs, I came to think that the ohms ratings are to guide the user to select a cartridge with internal resistance approximately the same as the ohm rating of the SUT. AudioNote seems to be using the numbers differently.

There is the Math to be considered, and it looks like how Math is used is debatable. 

There is also the knowledge of the producer of the SUT to consider.

I feel confident the experienced  producer who does assess sound being produced from their designs, is knowing much about Core Metal, Wire Types, Coil Winding and Final Assembly that are contributors to the qualities detected within an End Sound.

As this type of knowledge would be seen as IP it would not be expected to be discussed in detail. 

....

AN-S4/M - 27.5 Ohm input impedance - For cartridges with an impedance of 7 to 9 Ohms

note that 7 x 4 = 28

AN-S4/H - 48 Ohm input impedance - For cartridges with an impedance of 12 to 16 Ohms

note 12 x 4 = 48

so, their input designations are 4x the lowest coil impedance, WTF?????

 

The published input impedance of the various Audio Note SUT's are specified for a 47k input. They state on their website that they believe MC's sound best into a load 3-4 times the internal impedance of the cartridge.

Their stuff sounds awful anyway so does it really matter what their beliefs are ?

MC- Step-Up Load Calculator

By Consoludated Audio

https://www.consolidated-audio.de/en/calculator_view.php