Voltage Regulator for built Preamp

Here is what I am trying to do:I built a microphone amplifier out of a LM386 circuit(its a computer mic, an elect microphone. by the way, i forgot the exact name but i know the mics that require external power starts with 'elect' , whats the name of it again?). I am trying to power it with my cars 12v supply but when i hook it up, it pics up the engine noise and all the other noise thats on the 12v+ line. I was reading that cd player pre-outs are powered by voltage regulators, it steps down the voltage to clean up the 12v+ line so its a clean supply. I am guessing this is what I need to power my microphone pre-amp also. WHen i have it hooked up, my ALpine cd player has an aux input with 2 RCAs that i hook my mic preamp to. Any suggestions? Are my thoughts correct?If they are does anyone have any suggestions of a voltage regulator that i could use to step down the voltage to around 9v, or is that enough to cutout all the 12v+ supply noise?Why I think its the 12v+ noise:When i have the car off, but only the cd player on, the fuel pump doesnt 'prime', the cars computer isnt on...noting is on except the cd player and my amps. When i turn the key to "on"(but not 'start') the fuel pump primes, the cars ECU turns on and everything has electricity goin to it, except the engine isnt on. WHen I start the engine, the fuel pump is on, everything is on. also i can hear the alternator noise. its not only the pitch sound when u get induced noise into the signal cables but i can hear the pulsating noise of the alternators AC signal rectified into DC. i know thats what the whine is but this is more of the high pitch sound AND a more pronounced pulse sound. Any comments is greatly appreciatedPS: I found some items on the LM317 variable voltage regulator. anyone suggest using this, or is it what i am looking for?

here is the schematic for the  if that helps at all

You may want to resize your image if you want anyone to look at it.  Its a little too big.Kevin Pierson

right click and save it, you'll be able to see it better. on your pc.Shaking The Neighborhood

First, the word you are looking for is "electret" but just because it requires a power supply, that does NOT mean a microphone is "electret". Electret means solid state, as opposed to dynamic. Second, stepping down IS NOT filtering... Not even CLOSE. You need to filter your DC before you present it to th VR. Third, the LM317 WOULD work, but look for a 7809. Three terminal, fixed voltage, 1 amp current capacity with heatsink, absolute minimal parts requirements... 12v IN, 9v OUT, GROUND... That's it. For your application, you probably wont even have to have a heat sink. This will be the easiest way, but you will still need some supporting filtering before it... and MAYBE, depending on the severity of the noise, a small filter after it. PM me, and I'll see what I can do about drawing something up for you. It shouldn't be expensive - the 7809 will only cost about 5 bux, and it'll be the most expensive part, probably...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."