pioneer DEH-345 in my room w/ a sony amp

get yourself a voltage regulator.gcorrea

In more depth, you need a power supply that can put out enough current at 12 volts or higher to run both the stereo and the amplifer.  You need to know about how much current these two devices with draw.  You can get a basic idea by adding the fuse ratings of each device.  Your power supply will have to supply about that much current in order to get the wattage that your amp says it can put out.  You'll find out that this will be an actual amperage rating, not a milliamp rating.  Therefore, watch what you get for your power supply.  There are a lot that put out 12 volts or more, but in milliamps, not amps.  If the current output is rated in " mA " then that is milliamps.  It has to say something like say 12A or so.  Not specifically 12A, but one thing is for sure, a milliamp output won't play anything on your stereo.  Most stereos have a fuse rating of 10 amps now.  So you gotta have something in the 8 - 10 amp neighborhood to get the head unit alone to play.  Also watch voltage output.  12- 15 volts is acceptable.  Not lower and not higher.  You can get one that puts out like 80 amps and the stereo will only take what it needs from that, but if you get one that supplies a too much voltage, you'll fry it. audeogod

92 Chevrolet Cheyenne 1/2 ton truck

Pioneer DEH-41

Eclipse 2-way coaxial 4x6's in dash

Eclipse 3-way coaxial 6 1/2's in doors(cut to fit)

Pioneer GM-X332 amp bridged to Kicker 8" sub

where do i get the voltage regulator?

try radio shack they might carry onegcorrea

You can use a power supply made for a computer. You can buy one with ~30a at 12v for between ~$25~$75. Then you need a specific made switch to turn it on. This can be found at most electronic stores

You can also get on eBay.  My friend bought a 80 amp output on there for about $75 also.  It was a Pyramid brand, which as we all know is NOT a good car audio brand, but his power supply works really well so I'd say it was worth it.  audeogod

92 Chevrolet Cheyenne 1/2 ton truck

Pioneer DEH-41

Eclipse 2-way coaxial 4x6's in dash

Eclipse 3-way coaxial 6 1/2's in doors(cut to fit)

Pioneer GM-X332 amp bridged to Kicker 8" sub