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

Dear @drbond : About quality level performance in SUTs the best regarded/build transformers are: the Hashimoto 7, the Altec 4722 and Tamura TKS83. Lundhall or Jensen are in a lower " league ".

Altec and Tamura are not in production any more, at least to my knowledge. Btw, the gentleaman behind HM-7 is Isao Asakura.

Denon choosed a special custom design Tamura transformers for the AU-1000 ( Denon use the standard Tamura in its AU-340 that I own too and modified too. ) and here what a true music lover and SUT expert said about ( he already tested the Lundhall, Jensen and others. ):

 

" HM-7 sound falls somewhere in between the organically detailed and dynamic TKS83 and the rich and spacious airiness of the classic 4722. "

No one of then are transformers silver wired but are the best of the best in SUTs.

 

Btw, the AU-1000 Tamura transformers are better than the others I named here. The Tamura in the AU-340 is the one reffered by that gentleman full comparisons.

 

R.

In all subjective evaluation, one individual's selection of a Top Five is potentially the reject list of another individual.

It is the wonderful reason why the owners of systems that have built them up over time with selections made to meet each's unique preferences, are mainly all different assemblies of devices to perform quite similar roles. 

Pumping Products are just that, products being pumped, they are not answers to what an individual is really attracted to and can quite easily prove to be a repellent to an individual.

This thread and many others within multiple forums are testament to how diverse the selections are that make up a system, which basically means Budget, Experiences, Attractors and Repellents are very much at play.

Experiences are where I encourage an individual to grow, with these under one's belt, the Budget required is beginning to be realised, the satisfaction that can be had through committing to a design/build that is an attractor, will certainly produce a customer who stands sure in their choices.      

In practice my SUT experience was disappointing. I used highly regarded Cinemag transformers with my Lyra Delos cartridge perfectly matched. The sound was energetic and loud but the treble was edgy and grainy.

Using my Sutherland 20/20 fully active without the SUT sounded much better.

SUTS are something you add if you do not want to purchase a good active phono preamp. My experience.

I don’t doubt your experience. But I’m simply curious as to which "highly regarded" CineMag you tried? Quite frankly I found their 3440A (possibly their most common SUT) to be bad. I hope yours was at least a blue-label (better laminations) model other than the 3440 - they are MUCH better imo.

Every system & ear is different. Most will regard the MC stages of Herron VTPH-2A and Audio Research Reference 3SE to be at least "good", but in my system they both lose out to a well-selected SUT - for multiple MC cartridge brands & makes which I have in my collection. But you have to pick the "right" one! That goes for active MC stages, too. 

I used highly regarded Cinemag transformers with my Lyra Delos cartridge perfectly matched. The sound was energetic and loud but the treble was edgy and grainy.

This is the tricky bit about SUTs. This sounds like a classic situation where the loading on the output of the SUT wasn't addressed. Depending on the cartridge's source impedance, the 47K load that was probably stock in the preamp was likely not correct. This can result in distortion and the interwinding capacitance of the transformer playing a role like a capacitor in parallel with the transformer.

So not only would the result be distorted (likely causing harshness) but it might not be flat either! I can imagine this being quite disappointing. At any rate if the loading were addressed I suspect this situation could have been rectified without replacing anything.

Dear @mulveling  : SutherlaND 20/20 mk2 IS A VERY GOOD ss PHONO STAGE DESIGN ( LIKE THE pS aUDIO sTELLAR. ) AN YES BEEN an active high gain design just outperforms I think almost any SUT.

 

Here a review from 2011 and read it and please read carefully its measurements including the overload numbers and this Sutherland humble price tag as the PS Audio Stellar always be a challenge for any other phono stage surrounded by a good system:

 

 

 

R.