Preamp... Solid State or Tube

The Modwright preamp should mate well with your Modwright amps, and they do have the required HT bypass option. I would lean towards the LS100 over the LS36.5 because I like the 6SN7 tube better than the 6H30, but obviously your tastes might vary.

http://www.modwright.com/products/ls-100-tube-preamp.php

I'd also recommend a VAC Renaissance Mk III as a second option.
It also has the HT Bypass mode and sounds incredible.

http://www.vac-amps.com/productPages/RenaissanceMk_III.html

How about this:

 https://www.audiogon.com/listings/solid-state-pass-labs-xp-30-preamplifier-2016-03-08-preamplifiers-...

You'll probably get it cheaper & spend the savings on a loved one...!!

No doubt the Modwright LS-100 should be a top consideration, with the 150SE amp. As I understand, the difference between the LS-100 and the 36.5 is the latter is a bit more refined sound  and the former has more warmer tube sound. So it is becomes a matter of taste to which one fits your needs.

I have the MW 150SE and the LS-100 in my system and am very satisfied with its sound.

@adg101,  can you elaborate on your experience with DiD's?  I have been on fence to try isolation devices with my DAC or CD player.  All of my equipment are housed in a customized component rack that is preloaded with damping materials to create a high mass, low resonance core. 

http://coreaudiodesigns.com/products/component-racks/

Back to preamp, I am looking for fully balanced circuitry from input to output. Both LS-100 and 36.5 are nice preamps but they are single ended design.  

Until Dan comes out with a fully balanced Linestage, I would like to explore what else is out there. 

I can see why it would make sense to go with MW linestage since I already own MW's amp and DAC. IMO, balanced circuitry yields much better overall sound. 

Thank you all for your feedback. 

@jmcgrogan2,  I never heard of VAC until now.  And I am quite intrigued by their Statement Line Preamplifier.  Too bad, I can't afford it :-)