@jake18aa +1 on Nicholas's customer service. He took all the time in the world to talk to me about the questions I had on the LTA MZ3 preamp. In fact as I was ready to end the conversation he mentioned he had a few months old MZ3 trade in for sale that was basically brand new, and I bought it, with a nice discount. To this day if I have any questions he emails me back always on a timely basis.
I've haven't had the chance to hear the NOS 1943 Tung Sol black glass/round plates in my system as my next purchase will be the NOS 1952 Sylvania 6SN7GT Bad Boy. So if anyone ever tries these tubes in you 'new' LTA Aero Dac, I would really enjoy reading that review. But I must say the LTA MZ3 comes with NOS RCA 12SX7GT and NOS Brimar CV4024 tubes or whatever replacements they may have on hand at the time, such as the Genalex E88CC.