Step up transformer or upgrade phono preamp?

I am not against SUT's when implemented by designer as part of the system. But that is a far cry from the typical consumer who buys a 3rd party SUT and installs it with their phono preamp because it doesn't have enough gain.  I believe that boosting the gain is the only reason to have the SUT. I've done it before many yrs back but it was a patch for a problem of lack of gain with a MM phono preamp. So what am I missing?

I can't imagine adding a $1k Denon SUT to a $600 phono preamp. That just seems wrong headed. With the extra cable you will have even more expense. That $1100-1200 can go a long way towards a better phono preamp. Why boost an inferior signal when for the same $$$ you can get a better quality signal with proper boost? Am I missing something?

The assertion is that MM phono-pre is more easy to make than
(complex) MC -pre. The other is ''the higher the amplification the
higher distortions''. $ 600 preamp does not imply ''bad preamp''. 
There are ''only MM'' kinds. SUT like Denon S1 can improve
the sound of an ''poor man'' system. In addition Denon produced
a speical cartridge for this SUT because of SUT's succes. The
cart is DL-S1 and can be get for less than $1000. 

Maybe a dumb question, but let’s say I went with an SUT. I’ve noticed that some SUT’s do not specify how much gain is added, it only shows the coil winding ratio. Is this another way of telling me how much gain would be added to the chain? And if so how would you convert it? 

Question isn't the dumb one. It's another way to tell what you'll get.
Although you have to match 2 things per once - step up ratio and impedance. 

Let me guess what is going on here. In actual listening, you have no problem with gain. Isn’t that correct? But apparently you looked at some chart or read someone else’s opinion and decided that you must need more gain, that that must be the problem, even though you do not perceive a problem with gain. Whatever is the case, you cannot assess the need for more gain simply by looking at the gain of your MC phono section. You also need to know the additional gain added by your line stage or the high level section of your full function preamplifier. After that you also need to know the input sensitivity of your amplifier. All of these things affect your perception of gain and the sound pressure levels you will get from your speaker. Of course the efficiency of your speaker in converting watts of power into sound pressure is another factor determining the gain quotient of your system. Someone else can look at a chart or do a back of the envelope calculation and tell you that 60db is marginal gain for your cartridge, but by itself that doesn’t mean a thing. If you are happy with the sound pressure you are getting from your speakers, then you do not need more gain. Like Miller carbon said, perhaps you would be happier with a better sounding phono stage, not necessarily a higher gain phono stage or the addition of a SUT. A SUT is just a transformer. It adds to signal voltage while reducing signal current by a proportional fraction. The added gain is directly related to the turns ratio of the transformer. Any manufacturer will state that somewhere in the literature supplied with the transformer. But before you were to buy one, you would have to do more homework and decide what turns ratio is needed for your system. To do that you need to take into account the gain afforded by the moving magnet section of your phono stage, not the MC section. You can read about the use of a step up transformer on the Internet. There are many good sites for that. In my opinion, unless you really are lacking in gain, you really do not need a step up transformer in your system.