amps are noisy
this isn't the first time you've mic'd an amp, is it? if so, i bet what you're hearing is the general hiss that pretty much always comes from an amp. a lot of times we don't hear it when we're just playing (or we tune it out), but mics don't.....they pick up everydamnthing.....and it seems like they excel on picking up amp hiss. ;-P since you said that it goes away when you move the mic farther back, and it increases when you get closer, it's almost a guarantee that it's coming from your amp.
a couple questions to help flesh this out--does the hiss "go away" when you play? does it get louder when you crank the amp (while not playing)? and are you sure it's not coming from the gain that you've got (more than likely) cranked on that 414? i've used those things before, and they're not quiet when you've gotta turn it up to compensate for a quiet source.
i'll be honest with ya, though, few things sound more anemic than an amp turned way down low. if you can't get it to a good volume before recording, you're probably going to be less than thrilled with the results on playback. if disturbing the neighbors is a regular concern, you might want to invest in a POD or some other flavor of amp simulator. it might not be the best solution in the world, but it'll prolly be better than micing an amp on 2.
cheers,
wade