2. analog
  3. 128100-10021

SUTs and Resistive Loading Questions

Hello, I have a few questions about SUTs and adding parallel resistors to reduce the load impedance.

I have a SUT with a 1:15 turns ratio. As we know, the load for a 1:15 SUT through a MM/47,000 phono preamp would be: 47,000/15/15 = 209 ohms.

However, I want a load impedance of 100 ohms for the MC cart I'm using. To calculate the value of the resistor I need to add in parallel to do so:

100 ohms = Z/15/15 for a SUT with a 1:15 turns ratio. Solving for Z = 22,500 ohms.

Resistor Value Needed = 1/((1/22,500 ohms) - (1/47,000 ohms)) = 43,164 ohms.

So now, my questions...

If my phono preamp has a 100 ohms load setting, can I use that (instead of the 47,000 ohms setting and the above calculations for adding parallel resistor) to essentially get the 100 ohms load impedance I want?

Also, is there any difference in damping using the first method versus the second method? I would think not, but not completely sure.

Thanks for your insight.
Ag insider logo xs@2xedwyun
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edwyun OP
244 posts
 
I agree less is more (and thus don’t like using more connections, resistors, etc, than necessary), but this is about trying different loading with a cart/SUT/phono setup to see what sounds best. If the resistors make a difference, then I would most likely change to a different SUT with different loading characteristics.

But I disagree that adding a SUT alone to a phono stage would lead to sound degradation. To me, the benefit of a SUT is not just gain.  YMMV.




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rauliruegas
13,074 posts
 
Dear @edwyun : It's your privilege to disagree.

R.
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edwyun OP
244 posts
 
Free opinions and free speech.
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