Best MC step up transformer

Your Audio Research has 47dB of gain in MM mode. That is a bit higher than a normal MM phono that has 40db.  You  also did not specify which Urushi you have. It is important to know that so you can get the proper match.

The best, well thats debatable. As mentioned by leemark, the legendary Stevens and Billington tx103 SUT's are as good as it gets. But you can only buy them through Music First now in their own device. I owned the Bent Audio SUT's that used the Stevens and Billington tx 103's. Long out of production and hard to find on the used market. Very high on the "cool factor" and exceptionally well made. 

If you can afford it, the Ypsilon Moving Coil Transformer is as good as your going to get in whats available retail. Used, almost never find a used one. 

Dear @charliee   : The best SUT is NO SUT.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

@ rauliruegas  

I agree sir, but that wasnt the question. 

If phono-pre (MM etc) isn’t good, there is no SUTon earth, which can help!

I found Phasemation T500/T550 the best SUT for my MC carts, Including AT-ART7/PhasemationPP300 connected to Accuphase AD2850 Phono-pre.