I have this DAC and suffered through the same tube problems as described here. Some vendors were kind enough to replace the failed tubes but upon return found the "blown" tube worked just fine for them. On another forum I read about a fellow who had the same problem but after his Alpha had been modded the problem went away. Turns out there is an issue with the tube heater circuit on the left side that is a simple fix for someone who is aware of it and handy with a soldering iron. I'm not so I had my unit repaired by RHB Sound Dezign (302-723-7549) and it has been free of tube issues for many years. I am running the Sovtek LPS which would not work before the repair.
