I have a 12" Apple PowerBook. It doesn't have a mic jack, only a line in. If you use a mic straight to that you get basically no sound (duh). So, I've been using my little gem 1/2watt guitar amp as a preamp. I plug the mic into that, and then use the speaker out on that into my laptop. I monitor the levels on my laptop making sure I'm not peaking too much.
Here is the schematic for the little gem: **broken link removed**
No, it should be no problem, the voltage output of the amp won't be very high anyway - if you really want to feel safe though, feed it via a resistor to the laptop.
That range sounds about right!. Your laptop should handle those no problem, a tiny amp like that dosn't have enough ouput to damage anything. If you like, insert a 10kohm resistor in the signal lead.
Also, to test the voltage, can I just hook the positive of my multimeter to the + on the speaker out, and - to ground?
And it read between 2.5 and 3.5 volts for the levels I had been recording at...seems a little high to me. So I may need to use a buffer or something at the end of the circuit.