Denon DL-103 and Audio Note AN-S2 SUT problem

Is the SUT new?  If so it needs some significant playing time to break in, and it could easily sound bass shy in the early hours.  Also, if it is new, you presumably bought it from an AN dealer in which case you should discuss the problem with the dealer.  Perhaps he can loan you another SUT to try.

To absolutely clear, I understand that you run the leads from the tonearm into the primary side of the step up transformer, then the output of the step up transfer feeds into the MM input of your preamp.  

Is there enough gain from this configuration?  Are you listening mostly close to full volume on your volume control setting or at the opposite end of the volume control range?  This might tell us something about whether you have problems with too little gain or possible overload of the phono stage.  

If you try bypassing the use of the step up transformer (going straight from the tonearm into the MM input), there will probably be insufficient gain, but otherwise, you don't have to worry about doing any harm.  If the sound is better, you have an issue with the step up transformer.  In the sound remains the same (albeit softer), then you might have a problem with the MM phono stage or the rest of the preamp.  If the preamp sounds good with other sources playing into the other inputs, that would me the phono section is suspect.  How does the M6 sound with other sources?

If you can take the M6 and step up transformer to your dealer, you can try it there to see what things sound like.  

Apart from gain/overload issues, most step up transformers sound reasonably good even when there is not a theoretically ideal match in terms of cartridge source impedance.  A really bad, thin sound suggests a failure somewhere and not just a mismatch of components.

Thanks very much for your reply. I discussed it with my dealer who are Audio Note dealers. It would seem there is a problem somewhere. Like you said they confirmed that the combination is not the ideal one but it will sound quite good when working properly.
Connection is TT to SUT input
SUT output to M6 phono input.

M6 line inputs all work fine. 

Next I am going to try plugging the TT into the M6 phono to see if the sound is different albeit quieter.

Will post my finding later

So I plugged the TT straight into the Phono.... Same sound quality low gain. I then reconnected the SUT.. Same sound quality and low gain. 

SUT is used. 

Must be that the SUT has an issue.

I will get it checked out.

Thanks for all the advice folks.

Cheers

After closer reading of your suggestions it could also be the phono stage in the M6 as the sound did not change. 

Thanks