Do I Need A SUT

@lewm You are correct on all accounts!

I replaced the DAC’s Transparent Super XLR cables with Kimber Select KS 1010 RCA cables. I use the Kimber cables on my R2R. The sound with the Kimber cables is noticeably better.  

I left the DAC volume at 90%, and tried various Stellar gain and input impedance combinations. The best combination was gain at medium and impedance at 200ohms. That same combination didn’t work as well with my BHK pre amp and Transparent XLR cable.

Now, both the turntable and DAC sound about equal in volume using the same LTA pre amp volume setting. Tomorrow, I’m going to put the Transparent XLR cable back on the DAC to see how much of change that will make.  

There is no particular reason to worry that the attenuators need to be set differently for analog vs digital, unless you’re prone to forget to turn down the volume before switching from analog to digital and fear speaker damage. Otherwise I personally set up analog gain for max SQ regardless of high level inputs.

Did you buy the better LTA pre with the Lundahl transformer option ? 
well worth the  $$ and in your unit you have a 3 way dip switch for gain 

You should be running all the same xlr throughout  for best synergy .

@audioman58 

The LTA preamp has the Lundahl transformer on input to convert it to SE. You can only use XLR there. The rest are all RCA. Changing the overall gain won't change the difference in level between his phono pre and his DAC. 

@lewm Sometimes, I like to A/B listen to the same album streamed from Qobuz or Tidal and played on my TT. Having the volume of each close helps with that. The LTA remembers volume settings for each input, so I don't worry when I switch from the streamer to the TT, to the R2R.

@audioman58 I have the Level Two version:

• Preamp output cap upgrade: The headphone and the preamp outputs have been separated, and different types of output caps, optimized for each output, are installed. The preamp cap is upgraded to a premium Clarity CMR.

• Power supply cap upgrade: The power supply caps and power storage caps on the audio board are changed to Mundorf Mlytic AG capacitors. The total amount of storage is increased by 22,000uF.

I'm quite happy with the SQ improvements the RCA cable and TT setting changes had on my system. 

The Kimber cable improvement was unexpected. Voices and instruments sound more natural, there's more separation and definition between them, and the sound is a bit warmer with no loss of detail.

My TT has always sounded great to me. It has always sounded slightly warmer and more full bodied than my streamer.  

These improvements cost me $0, and just a little experimentation and time.  Thanks to everyone for your insight and help.