Good advice from KingofPain.
I bet it might even be a little solid state 15 watter. Even the new 5 watt Marshall tubes are LOUD.
I also think its best to use a large diaphragm condenser mic what recording with very low volumes.
He was right about the distortion & EQ. You can fix the EQ after the fact, but you cant add or reduce distortion. Here's what I do...
Record 2, 3 or even 4 tracks of the same thing with different levels of distortion. Then during mixdown, you can try them out un-muting one at a time.
It really makes processing a simpler ordeal.
Good luck.