Choosing the right SUT for my setup

Using a high quality passive SUT is the best way to step up a low output moving coil cartridge, run into the moving magnet section of a phono preamp, especially a tubed phono preamp, of which most use electronics to step up the voltage in mc mode. The exception being the Tavish Adagio and the Ear 834p (& I'm sure a few others) both of which use built in transformers to do the job.

Here is an excerpt from Jensen Tranformers website....

Once connected, the Jensen moving coil step-up transformer (SUT) is best described as a passive signal amplifier that does not color the tone or add artificial flavor. It is made for the purist. It does not try to impress with enhanced high frequency detail or exaggerated bass. It simply delivers the goods in its most transparent and natural form.

There is a lot of misleading nuisance being written here against the use of SUT. Utterly incorrect. Unfortunately the OP seems like a newbie and he will take away a very distorted confused view about this whole SUT game.

To the OP, a good SUT like a Denon AU-340 will beat the MC section of many/most $10k phonostage but you have to get the right match for your cartridge. For your carts you need a 1:20 SUT to sound tonally correct, with proper gain. If you go for 1:10 like the ones in AU-320/300/340 it will sound too bright and also lack gain. There are ways to match the impedance by adding a resistor but it is a dirty route especially for you as a starter into SUT. So here are couple of options

1. Get a 1:20 Cinemag Blue SUT and it get it installed in a nice box with termination. Bob's devices is a company which sells this SUT for Sky (pun intended) high prices just by installing it into a good box. The SUTs are already built into a mu-metal can so any good box would do.

2. Get a nice multi-tap SUT like Ortofon T-30. It has 4 gains for different impedances including one for 12 ohms.

SUTs can get very expensive. If you want to spend more, there are options like EAR MC4

artemus_5, you keep saying there is another component in the path when one uses a SUT. With a built in active MC stage there are a LOT more components in the signal path, look at any MC stage schematic for verification. A high quality SUT will amplify the voltage while taking away or adding nothing. It's the beauty of a SUT.

BillWojo

I have owned a few SS Phon's, a Valve Hybrid Phon, and a Valve Input/Output Phon', I have the two Valve models maintained as keepers.

Additionally whilst on the Phon' Quest, I have experienced through demonstrations, quite a few Phonostages at Bake Off's over the years.

I have heard compared to each other a wide selection of SS Phon's with a 'in built' MC Stage, along with multiple Valve Hybrids and lesser Valve Input/Output.

Not all SS Phon's are equal, I say that with asurity, many topologies are similar and there is a much of a muchness experience encountered, these designs can soon be discovered to not leave too much of a positive impression. Occasionally there are SS Phon's encountered, that are produced using a different topology, and certain models, be it from a Brand or a DIY Build can make a impactful impression and one I would like to experience in my home system. I wouldn't hesitate to try these as a MM > SUT vs the 'in built' MC Stage.

I am yet to discover a Valve Hybrid following a demonstration at a Bake Off, that has made myself want to use it in my home system. The MC Stage does not deliver in a way that I find impressive, and similar designed, but differing models all have a related sonic signature, especially when Jfets are in use. These designs have not conjured up the desire to bypass the Jfet and use the MM > SUT.

My own Hybrid has a different design to a Jfet for the MC Stage, it has a Transformer and has also has been Tube Rolled, I use this most commonly with a SUT, but as it has a multi adjustment function on the MC Stage, I will occasionally use it with a Cart' and produce various settings to see what can be achieved. The Phon' has been given up for extended loan periods and the users have ended up adding a SUT. 

The Valve Input/Output Phon' I use, is a Bespoke Built Design and has developed through a few build guises.  There is an 'earlier prototype version' that has been demonstrated in a Bake Off where Phon's were present up to five figures, it held its own in this Company.  The version I is the latest version with a selection of components in use of my choice. It was also discussed to have an 'in built' MC Stage, but I was reluctant, as I knew the options for it and it seemed limiting to my requirements. I chose to remain MM and have a large selection of SUT's and Head Amp's to experience.

The Valve Input/Output Phon' that I was recently demonstrated the Structure A SUT's through is the referred to 'earlier prototype version' of my own one, hence my keenness to have a home demonstration when up and running once more with the system. 

My experiences of using a SUT and Head Amp in A/B comparisons leads me to suggest that Head Amp's I have used, are best described, as being transparent and the SUT's I have used can be perceived as being Noticeably Rich, Rich, or having a Hue of Richness.

These variations in how a Step Up device presents, allows for a lot of options for a user increase their enjoyment during listening, as their is a option to select a device that will present very closely to their unique tastes and preferred presentation.