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

Resulting from my discussion had with designer/builders of Amplifiers, there are considerations and preferences in place for the Core Materials to be used and the optimisation of the Windings for specific designs for a Transformer.

I have Power Amp's with Hand Wound Optimised Transformers for both the Power Supplies and Output.

My Valve Input/Output Phonostage is with a Hand Wound Optimised Transformer. 

One of the SUT's in use is a Hand Wound Optimised Transformer.

The SUT's I am keen to experience in my system at a later date are also with optimised Transformers.

Not all Tranx's are equal, I have this info' supplied from valuable resources.

There are those that have a design that will perform a role, and meet a broad spectrum of requirements, these are not optimised to a be used for a Specific role. There are those optimised through design, to perform at their best when used to cover a limited role.     

In Japan, I have even seen the Winding Material taken to the extremes, where it is a material used with a proven progeny, i.e such as removed from a Submarine built from a particular decade prior to the Millenium and used with a specific type of steel as a Core material. Not known, but I would assume, these are used to produce an optimised design for the Tranx to be produced. 

A friend last year, designed and built a Direct Coupled Phonostage, based on the Model I own. Each Transformer in the circuit has a Hand Wound Optimised Design, produced from a certain type of wire for each unique role within the Circuit.  

@rauliruegas

Btw, could be interesting that your friends can ask to EMIA its measured FR due that even that exist audiophiles that just do not care about that kind of measure is really of critical importance and the manufacturer just " dead silence about " and I wonder why because other SUT manufacturers gives that kind of measure.

it seems you are really good at scouring the web and quoting other people and less adept at researching/understanding what other people write. If you click the link provided in this very thread by @antinn on 11/16 you will see the actual measured frequency and phase response of an EM/IA SUT compared to the venerable Altec 4722.

dave

Thanks @intactaudio.  Your SUT has made a big difference in the quality of my friend’s stereo.  It works wonders with his Lyra and Marantz 7C pre. I think my listening impressions had a lot to do with my system, the cartridge and what I like.
I enjoyed hearing the differences but they were not what I expected. I bet if I brought my XP-27 to my friend’s system and swapped out the SUT, his stereo would loose some of its magic.  

Btw, what atmasphere posted was theory that today it just does not happens and all that that you can use balance cable connectuion to the phono stage because th SUT is bs

@rauliruegas Clearly you have no idea of what you are talking about.

Transformers are very good at converting from balanced to single-ended and vice versa. Jensen Transformers does a very good business on this aspect of transformers alone. Most SUTs are built for certain cartridges, and so have single-ended connections, but if the SUT in that box were examined closely, it would be seen that its actually a simple matter to set it up for balanced operation.

Here is how its done: The SUT has a total of four connections, two as input and two as output. There may also be a ground connection, which is connected to the core of the part (not needed if the transformer is bolted in place). You have to identify the input (the primary side) and the output (the secondary side). If you want a balanced input, tie one connection to pin 2 and the other to pin 3. Pin 1 of the XLR will be the case/core of the transformer and is where the ground connection from the tonearm will go. The tonearm cable will thus have the + and - outputs of the cartridge traveling in a twisted pair to pins 2 and 3; the tonearm ground becomes the shield of the cable.

You do have to be careful about phase. If you mix it up, one channel could be out of phase with the other, which will seem like a loss of bass impact (and if your system is very good at imaging, the music will seem to sit in the speakers rather than in space).

Raul, when you have the idea that you want to make someone else wrong, try to resist the feeling to post. Its obvious to many here that when you don’t resist that urge, what you write isn’t correct, with the motivation is really obvious. It does not become you or lend credibility.