EL34s in Series One SOLO 50?

[square_one]

When I bought my Mesa it had EL34s in it. They had been in there for 15 months. I am getting it retubed and the tube resistors replaced (they died on me after only having it like 4 days). It has MESA EL34 tubes. Would this be a problem? I know it is fixed bias so I should use 6L6s. But I am wondering if they maybe had someone adjust the bias on it when they had it retubed before? Could they have ruined anything just popping in EL34s and calling it a day? I doubt this is what happened but I am just curious.

My guitar tech guy hasn't tubed it yet so I am just trying to find out what to do before he gets in to it.

 

[stadidas]

The series one is biased for 6L6s and nothing else. However, what I did was look at the schematic for the bias select on a Dual Rec, and copy it. I installed an extra resistor in parallel which I can switch on with a switch mounted on the chassis, allowing me to use EL34s (of the Mullard variety, which I prefer). You could probably do a similar thing.