This has probably been covered already but I can't find it.
I've been recording direct thru a pod forever and have just started playing with mic'ing my amps. I've got a shure sm57 and have that plugged into my soundcard. I set my levels so I'm just to the point that I'm not seeing any input clipping but when I record my waveform looks really small and I have no volume. I just wonder if I should be using compression as an insert effect on my channel and boosting the input levels. Also what to set the threshold, -1db, -3db, -6db?

Before looking into that, I would check your computer's soundcard settings first. If the input is at the point of nearly clipping, then you should be getting a very fat waveform. Something isn't right here. What kind of soundcard are you using, by the way?

You need to preamp that signal. Get a cheap Behringer or a Presonus Tube Pre.
Then use the compression on your software.

You need to preamp that signal. Get a cheap Behringer or a Presonus Tube Pre.
Then use the compression on your software.

Haha, didn't even think to tell him that. The simple things are the most overlooked. Yep, gotta get a preamp between the mic and the soundcard to boost the signal. The idea is to have the guitar amp loud enough so that feedback will build up slowly. Then play the loudest you can play and adjust the gain on the preamp to come just before clipping. Also, watch the input on your software as well and take note if its below the clipping range. A lot of preamps have a limiter on them, but I say if you gotta use that, you have your preamp turned up too high. No need for that.

I plug an SM57 into an Art Tube MP Project series...works great for me and its only around $65 on americanmusical.com.