Sorry, your power transformer is made for 6L6 not EL34 and will not handle the additional current needed for those filaments......
Is anyone using EL34's in there Bluesmaster or HRM? If so what mA are you setting the bias for? I'm using Winged C (SED) 6CA7's.
That's a classic Internet misinformation statement... If you use the Merc trannies spec'd by Nik, and I understand that he specs 2 different trannies depending on whether you intend to use 6L6 or EL34, either set will handle either power tube. The Mercs are built like tanks and have power to spare.