When is a mic preamp needed?
 

I am setting up a sound system to do voiceovers on a routine basis. I am leaning towards putting the mic signal into a Canon GL2 rather than directly into a computer. The reason for this is that the computer is quite loud and from my computer room I can hear birds and kids playing outside. But I have discovered that my small walkin cloths closet is pretty dead and amazingly quiet. After reading past threads on this forum I was thinking to use a Rode NT1000 directly into a GL2. I would then use headphones and the GL2 audio meter to moniter the audio signal. My question is do I gain anything if I use a mic preamp when I am using the camera to record the audio? If the preamp is needed what types are necessary to do a decent job with a mic of this quality? (NT1000)

The GL2 pre is decent, but it won't come close to what you can get with a great pre. It's all about budget. On pre's, I'm a total snob. With a great studio front end, nothing else matters, not really....
I just got the new AT 3060 tube mic, and going into my John Hardy M1, it's simply AMAZING how fat and round, smooth and silky it is. I've got a buttload of studio mics, but the matched combo of certain mics and pre's is hard to beat.
The Avalon is a great pre, so is the Haemer. Both are VERY expensive.
In the lower end, Digitech makes some good pre's, M-Audio does too.
And if anything over 200.00 or so is out of budget, then the GL2 will compete fairly well.
But that's just my opinion. I'm sure you'll hear lots more.

John Hopkins? Maybe you should have been a doctor.

You'll need an interface of one kind or another 'cause you can't run the NT1000 directly into the GL2. XLR issue. If you have a Beachtek or another adapter then you probably already knew that...

You could actually round out your setup with the Beach Tek DXA-8.
it'll give you preamplification, limiters, phantom as well as XLR inputs and it will attach to the bottom of your camera.