SUT (they are tricky, I got help here, did research, scratched my head, learned this).
Consider selected and future MC cartridges when choosing a SUT (or phono stage with MC):
You need to know both the cartridge’s signal strength AND it's coil's impedance to know what range of xFactor (enough but not too much gain) and that xFactor’s resultant impedance (that will be shown to the MM Phono Input).
Thus you want a SUT with several options of gain (xFactors) AND each of those xFactors give a RESULTANT impedance that will go to the Phono Stage's MM input (separate or in a Preamp).
Some equipment has independent options for gain and for impedance, they usually cost more, but are needed for some MC cartridges with signal strength/coil combos that need that separate adjustability. Best flexibility for unknown future cartridges.
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FORMULAS
GAIN = xFactor = +____db.
xFactor squared = _____?
RESULTANT Impedance ‘shown’ to MM Phono Input _____?
47,000 (common MM phono stage is 47K) divided by xFactor squared ____ = impedance shown to the MM phono input (check your equipment’s MM Phono Input impedance, some not 47k)
The guidance for impedance shown to 47,000k is cartridge coil impedance __ x10.
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example: for current and future MC cartridges (including my friend’s cartridges we listen to here): I chose Vintage Fidelity Research FRT-4 to get PASS and 4 optional xFactors and their resultant impedance
Some/this SUT’s face numbers are confusing, I had to find the specs to know what the face settings meant: how much gain/resultant impedance shown.
PASS (for MM or High Output MC) bypasses transformers, unchanged signal to MM input
Face 3 ohm = xFactor 35.84 (+31db). 35.84 sq = 1,284. 47k/1,284 = 37 ohms shown to MM input
Face 10 ohm = xFactor 20.68 (+26db). 20.68 sq = 428. 47k/428 = 110 ohms shown to MM input
Face 30 ohm = xFactor 18.27 (+25db). 18.27 sq = 333. 47k/333 = 141 ohms shown to MM input
Face 100 ohm = xFactor 10.55 (+20db). 10.55 sq = 111. 47k/111 = 423 ohms shown to MM input
Luckily for me, it also has 3 tonearm inputs, front selectable.
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this shows it (ding in face panel) (price a bit low due to that)
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Entre ET-100 is similar (black or silver)
Other SUTs with flexibility can be found
IF you or anyone wanted a New MM/MC Phono Stage with Options, Project makes several among other companies
