Hi, I have a DT25 combo with a similar problem. The stock tubes measured 31.3 in V2 and 22.8 in V3. I put a brand new set of JJ EL84 matched pair and a 5751 (12ax7). Switched it on and started playing. Got about 5 miniutes playing and the tube fuse blew. It happened before I had the chance to check the bias of the new tubes. Stuck a new fuse in with the old tubes and its fine. I'll try and re-bias the new tubes after the weekend. I have a gig to play. I too am surprised by the different bias values for each valve and cant get them to match. I'm also surprised that a new set of EL84's would cause so much of a problem? Valves bought from Watford Valves. Never had a bad one before. Thanks.