Takamine Cool Tube: mics?

[JohnCovach]

I just picked up a used Takamine 132SC with the Cool Tube preamp in it. I'm wondering if anybody could help me with a couple of things:

1) How do you turn the preamp off? Once I replaced the batteries, mine seems to stay on (green light remains illuminated) no matter what I do, except remove the battery tray. This can't be right.

2) I'm eager to use the secondary input function to install an internal mic. Any suggestions on a good mic for this purpose?

[JohnCovach]

Aha--I discovered that there's a switch on the back of the preamp that bypasses the jack switch (why that would be useful, I'm not quite sure).

I'm still looking for suggestions for an internal mic, however.