Which Diezel? The Herbert may be different because it has 6 power tubers. I don't know about the Diezel but generally a pair is in line not inner outer as a pair. . I know when you pull two tubes to run an amp in half power it is usually the outer or inner pairs. This gives you one tube on each side of the output transformer which lends itself to tubes in line(inner to outer) being a pair on one leg of the OT.
