@designsfx , Thanks.
So far, no issues driving my Viva IA, from the Lampizator. Typically, when I switch between the Amp and the DAC, I let it run that way for a few months. Also recommend by Lampizator dealer is to turn the DAC volume between 1-10dB when used as a DAC....it adds some richness.
The only issue I had with the DAC, is that the left channel stopped working, it was dead and not a tube issues, it was repaired under warranty. There have been no problems post repair.