I purchased the Ref110 about 10 months ago and 6 months into the purchase I had a tube blow out on me with ~350 hrs of usage, which is not out of the norm. After replacing the tube and its matched pair (supplied by ARC thru my dealer), i had another tube pop on me yesterday (after another 300 hrs of usage), which seems to me to be a bit too frequent. I have all my electronics plugged into a Shunyata Hydra 8 power conditioner. Has anyone had tubes go bad on them on the ARC Ref110 this frequently or does this seem anomalous and does it suggest that there may be something wrong with the circuitry on my particular unit causing frequent tube failure which would necessitate shipping the unit back to ARC for service. Interested in other folks experiences with the reliability of the Ref110. Thanks much.