We used to mic both the front and the back of the amp—which is a technique that came from knowing how to record a French horn in a small room. We would lean a piece of plywood against a wall, put the amp about three or four feet from it, and drop a mic down between the plywood and the back of the amplifier. That would give you a pretty good sound.
We probably used that technique with Jeff—although we might have used a baffle rather than plywood. And I’m guessing we used a Neumann U87—just sitting down in front of the amp. Also, I like to mic the speaker paper rather than the cone. Most guys put the mic right on the middle of the cone, or they take a Shure mic and point it to the center of the cone. I don’t. I like to point the mic towards the paper to get the sound coming down the cone.