SUT suggestions for Audio Note System

Here are the specs for the M6 phono.
The overall specifications for the M6 RIAA phono preamplifier are an input sensitivity of 47 kΩ, an input sensitivity of 126 mV for 1 V output, an output impedance of <10 Ohms,

I would consult with your Audio Note dealer.  As long as the output of the cartridge does not overload the phono section of the M6, you would be able to use their SUT.  Most phono stages have sufficient headroom that the difference between .3 and .6 mv will not be a problem.  The Audio Note SUT are very good.  My local dealer who sells Audio Note gear and who sold Koetsu until their recent demise, often utilized vintage microphone SUT.  He liked these more than most conventional separate SUT on the market other than the Audio Note ones.  I once tried Audio Note's top of the line SUT and was actually relieved that it did not work in my setup (hum issue that defied all attempts to fix) because the price was quite a stretch.

@pkvintage You have several options. the output on your cart is around .6mv 

1.you can try one of Bob's step up devices, 

2. look for a used step up designed to work with that output level.

3. go all out and check out the Ypsilon step ups where they have several models available for the gain needed. 

The output from the Koetsu Black is .4mV and works well with a 1:20 step up.

Thanks Bob but the research I have done shows it being .6. There are 2 blacks. Mine is the early one if that makes a difference.