What tubes? Who? Me?What tubes? I searched in the workbench section but didn't see your comment? Most vintage Marshall amps have EL34 power tubes and 12AX7 preamp tubes.
I'm not in the workbench because my amps are not broken.
In my country we call them valves.
I am an adult and I believe I can't read a map very well. I always need to look twice and think about it. I am comparing myself to somebody that just needs to glance at it once.
I also can't read a circuit diagram very well.
It's nice that on a map you can trace a path without thinking 'what about induction?', 'this will cause noise'.