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SUT - electrical theory and practical experience

Some vinyl users use a SUT to enhance the signal of the MC cartridge so that it can be used in the MM input of a phono stage.  Although I don't understand the theory behind it, I realize that a SUT should be matched individually to a particular cartridge, depending on the internal impedance of the MC, among other things.  

Assuming an appropriately / ideally matched SUT and MC, What are the inherent advantages or disadvantages of inserting a SUT after the MC in the audio chain?  Does the SUT theoretically enhance or degrade the sound quality?  What does the SUT actually do to the sound quality? 

Thanks. 

drbond
rauliruegas
13,129 posts
 

Dear @phoenixengr  : " My point about the specified impedance along with the output voltage was to make the necessary gain calculations easier.  "

I was very clear and stated that my phonolinepreamp is an active high gain design and I can tell very good design or at least competitive today.

Why should I care about gain  when here I explained and told you that " other that SPL changes " whic other advantages? and I posted that we had not changes in FR.

I'm not talking of phono stage + SUT.

 

R.

rauliruegas
13,129 posts
 

Dear @holmz  : In the good old times cartridge reviews where really great with all the information you can imagine. Here the LOMC Ortofon MC2000 ( that I owned ), page 83:

https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1984-12.pdf

 

R.

 

 

holmz's avatar
holmz
2,328 posts
 

I am trying to figure out:

  • whether they generated a square wave with the same output impedance as the cart and fed the SUT with that.
  • Or if they had a test LP with a square wave
  • and then if it is a test LP is that square wave a triangular shape on the track to make an electrical square wave.

?

dover
2,353 posts
 

@holmz 

this one -

  • whether they generated a square wave with the same output impedance as the cart and fed the SUT with that
dover
2,353 posts
 

Dear @dover  : Yes I did it during the " thousands " of tests with the prototypes of the phonolinepreamp and through measures and listening tests the only parameter we can been aware was changes in SPL but not in FR but additional to that normally LOMC cartridges come with the " rigth " internal resistance to work very good looking those 100 ohms. Clearaudio is something espcial with those 50 Ohms.

There are plenty of MC's up to 40 ohms ( eg Benz, Dynavector, Sony to name a few ) for which 100 ohms loading in my view is killing the cat.

If your phono linear were stable you would be able to load at any value.

It would seem that any observations or cartridge evaluations posted by you with this phono stage would be jaundiced by improper loading. 

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