I built a15 L.E.D display With two decibel gauges for my sons computer that I removed from an old reel to reel taperecorder. the needles on the gauges move a little bit but not enough to make it look cool.should I use transistors to boost the output to the gauges I do not want to burnup the gauges (conn to speaker output) power supply is 12vdc 200 mamp

 

You could use an op amp with variable gain.

http://www.allaboutcircuits.com/vol_3/chpt_8/5.html

By using a potentiometer as the feedback & input resistor portion, you can turn the gain up slowly. Then you can put a drop of nail polish on the potentiometer to lock it in place.