Which SUT? .... for .3mv/10 ohms MC cartridge into 3mv MM input sensitivity

I found this which, if you scroll down has a chart for many cartridges by model 3, and a calculator where you plug your #s in

http://www.mh-audio.nl/Calculators/StepUpTransformer.html

I think I am getting this, lemme know if I got it wrong

i'm just doing some math to learn the formulas
of course when you know this stuff it's intuitive

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Impedance change factor is square of amount of transformer boost
47,000 (typical MM phono input)
47,000 divide by change factor = resultant actual impedance
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" The recommendation of Rothwell Audio Products is in line with Ortofon, Audio Technica and most other cartridge manufacturers - that 100 ohms is a good value for most cartridges, and that the exact value is not critical as long as it is well above the cartridge's source impedance."
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signal strength: enough, but avoid too high, say 5mv max (easy math)
impedance is what effects the sound
too low = dull. too high = too bright
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AT33PTG/2 is .3mv and coil 10 ohm impedance
coil 10 ohm x 10 = 100 ohm goal (average)
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working backwards from desired impedance average of 100

47,000 divided by 100 = 470.
470 is square of  21.5 (boost factor found working backwards)
.3mv cartridge x 21.5 = 6.45mv = TOO HIGH SIGNAL STRENGTH
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lower the signal strength means lower the boost means impedance goes up, just don't go up too much

IF desired max signal 5mv divided by .3mv = 16.7 signal boost.
16.7 squared is 279
47,000 divided by 279 is 168 ohms resultant impedance, not bad!
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typical boost 10x or 20x, not 16.7 unless custom built.

.3mv x 10 is 3mv, TOO LOW? (mx100z phono sensitivity is 3mv)
.3mv x 20 is 6mv" TOO HIGH?

I PICKED THE WRONG DAMNNN CARTRIDGE!!!
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Resistors, parallel with Transformer's secondary are a method of adjusting the impedance

i.e. 100k resistor across 47,000 is 32,000

"NO RESISTOR sounds as good as NO RESISTOR"

OMG

rauliruegas

happily my mx110z has 2 phono inputs

that denon au-320 has the 2 inputs and pass, but I would use only 1 input for rear tonearm’s cable: 3 or 40 setting for MC, and use the PASS for my any MM, typically my MONO, correct?

it shows 3 ohm and 40 ohm, how do I translate that into gain factor?

this guy says very nice, accepts returns
100% rating
https://www.ebay.com/itm/333632155436

In a word, no.  Re-read Almarg's post.Also, you are making this much more difficult than it needs to be.Start with the turns ratio of the SUT, which is another way of stating the boost in voltage it provides.  A 1:10 SUT will boost voltage by 10X, in other words.  The reflected impedance afforded by that or any SUT will be equal to the value of the input resistance of the phono stage (47K in the case of nearly all MM stages) divided by the square of the turns ratio (10^2 = 100).  So, with a 1:10 SUT and a 47K resistor, your cartridge will "see" a 470 ohm nominal impedance.  Since we know your cartridge has a 10 ohm internal resistance, you will be fine with a 1:10 SUT.  The ratio 470/10 = 47, is way higher than the minimum goal of 10X.  There is no problem with having a ratio of these parameters that is >>10. With your cartridge, you can also use a 1:20 SUT; the same 47K ohm input resistor is then seen by the cartridge as 47K/400 = ~117 ohms, which is still more than 10X the internal resistance of your cartridge.
In your final paragraph, you seem to be asking what happens when you parallel 100K with 47K.  I don't know where you got that idea, but maybe someone else talked about REPLACING the 47K ohm input resistor with 100K ohm (not paralleling the two resistors; replacing one with the other).  This is a little trick that one can do if one wants to use a particular SUT with a turns ratio that is not compatible with the internal resistance of a cartridge that has a relatively high internal resistance (e.g., >30 ohms) but a low output voltage.  For example, do the math for using a 1:20 SUT with a cartridge having a 20-ohm internal resistance; you'd want to use a 100K ohm resistor on the phono input side to achieve the desired minimum ratio of cartridge output to phono input resistances. With your cartridge, you don't have to think about doing that.  You can use 1:10 or 1:20, and there is absolutely no reason to wish you could fine tune the turns ratio between those two choices.
I don't want to confuse you further, but the 10X rule is "soft".  You can even get away with ratios a bit lower than 10X but not much lower.  For now, think of it as a hard rule.