Understanding the multimeter on preamp

I don't understand how exactly I am to interpret the multimeter readout when trying to determine my preamp output voltage.  I know to stick the postive to the inside and the negative to the outside.  Also, I understand that it could prove fatal to the health of the preamp output for the inside to make contact to the outside.  If anyone would be interested in explaining how I might go about making a wire that could conect to the RCA on one end and the split off into two separate wires, one being positive and the other being negative, I would be most appreciative.

Back to the multimeter...

1.  You can use alligator clip leads on your meter for safer connecting to the RCA.  Or

2.  You can have the RCAs connected to the amplifier, turn the gains down to minimum, and read the voltage across the speaker terminals of the amp.  See the well-know JL tutorial that shows this.

Use a test tone sine wave for a steady signal.  Read V AC on the 20 scale of the meter...displays in whole numbers from 20 volts down.  Voltage will vary depending on frequency.

You said, "I set my gains at just below 1/4 volume like Crutchfield told me to...".  You will not get this system set up correctly using such a plan as that.  Make your test tone CD, read the threads found in a forum search for "gain", and set you amp gains correctly.  You will be listening for clipping;  knowledge of the deck's voltage output is not a requirement.  Here is a thread to help you get started:  https://www.the12volt.com/installbay/forum_posts.asp?tid=75001&PN=1

And by the way, your post was very clear and you explain yourself better than most do. 

To "nouseforaname"...I finally took a look at your name...thats great...lol.  I knew about the speaker end of things being AC, I'm just still surprised about the preamp outputs being AC.  I thought that a DC preamp output collided with the power from the charging system within' the amplifier causing the signal to become both ampilifed and AC, however, it appears that an AC signal collides with a DC power source and creates an amplified AC speaker signal.  If I'm wrong, then just throw a few rocks and I'll get the picture.  I'm trying to put two and two together on how all this equipment works so that I can be of better help to my friends when they need help.

To "stevdart"...I only set the gain the way they told me to so that I could get an idea of what things sound like the way their people think. I mentioned it only to give some background for comparison to the whole "Front End Defeat" thing.  It was all just for clarity.

Thanks for setting me a little straighter you two.  If you don't mind though, want did the .363 stand for?  Was it just a crazy, off the wall reading that I got because of a wrong setting or is there some formula that I need for it to make sense?  I appreciate all the help and advice.

So, I need to be in the 200mA position.  I just set it to the AC volt spot, but there is an AC section that has numbers with a mA listed beside each number.  I figured those were intended to read amperage.  I do have a range button on here, but I'll have to go hunt down my manual to understand exactly how it works.

No, you're first assumption was right- mA is for current (amperage).  You're reading should be in ac voltage, as Steve said.