Pre amp? What schematic do i need?

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Alright heres what i am trying to do and what i have:

I have an Alpine cd player for my car. i installed an auxiliry adapter that converts the Ai-Net(alpines conenctor) to 2 rca female jacks(left and right input). What i am trying to do is hookup a computer microphone to the 2 RCA inputs.

What im wondering is, what type of converter do i need?
Do I need a microphone pre-amp to make this work?

Any info would be helpful. If its a preamp that i need, is there a schematic of a simple preamp that i could build that would just be used for the purposes of doin what i explained above?(not do anything fancy/expensive, i have electrical soldering skills, i just havnt done anything very complicated b4)

Any info would be greatly appreciated.
Well if your not going to use a computer, but only the microphone and hook it up to the cd player, you will most certainly need a microphone preamplifier because the signal from the mic is very very small. If it's a electrostatic mic it will also need a supply voltage.

There are many circuit schemes on the net for mic preamps, i however prefer the Op-amp based ones for the discrete transistor designs but both will work. I built a mic preamp for a while ago. Can see if i can find the schematic.

Yes you can run them on 12V without problem. But if youre taking the voltage from the cars battery there are many disturbance there. Spikes from the engine and other stuff so you need some filtering to the curciuts.

This circuit should do the trick. You could use almost any op-amp. NE5532 is pretty cheap and good for example. However before coupling it to some expensive car-audio system, try it on some non-expensive equipment first and check it works som you don't destroy anything!
Note also that R5 is supplying the mic with it's voltage. This means you can't connect for example a mp3 player because then you will probarly destroy it. R5 must be deleted if anything else that mic is going to be used.

Here you go, good luck with building :)

An externally hosted image should be here but it was not working when we last tested it.
Yes that's correct. These small capacitors dont have any poles and can be connected in any directions. The electrolytic capacitor has two "poles", a positive and negative side. It must be connected right. Either the positive or negative is always market out on this capacitor! :)
ok this is the last question that i can think of....on the variable resisor is just one end connected to the circuit and then the other end isnt? but the part with the aarow is conencted to the other continuous part of the circuit. im just makin sure before i build this. in a different type of circuit i saw that one end was grounded(the 'end' that just hangs there right now). thanks
alright tahts what i thought i was just makin sure:).

I just got back getting all of the stuff i need, i just have one question about what i ran across. I saw that there was 100 nano farad capacitors that were ceramic and ones that were 'metalized-film'. what ones do i use? i got both kinds. also thre wasnt a 8200 ohm resistor so waht i was going to do is put 2 10kohm resistors in parallel to make it a total of 5K ohm and then on the end of that parallel, i will put a 3.3kohm resistor in series...making it 8300 ohm(am i correct?), will this work or does it have to be exactly 8200?
crap! i was just about to solder that in a few minutes but ill go get a new resistor tomorrow, im dumb for seein that O as a zero in ohm. thanks again. i have most of the things soldered ontp the board i have, i bought the LM386N op-amp, is that one any good? i see the voltage goes to the #7 pin on the opamp, on my opamp it says "bypass" is pin#7, just checking but if i use this chip, is that the correct pin(the 'bypass' pin) that the voltage goes to?
Well, im sorry but LM386 isn't actually a Op-amp, and it doesn't have the same pinout as a normal Op-amp. It's a built in small power amplifier. Check the datasheet

You might use this thing to, but then you can't use the circuit scheme i posted. If you want to use this LM386 you can use the proposed example in the datasheet "Amplifier with Gain = 20" And add the 10k resistor to power up the mic
is there any op-amps taht can be found at radioshack that i could use with the schematic that you gave me?( also). i dotn want to have to redo all of what i did allready....for the opamp i got the 8pin holder for it so i could slip it out and put another in so its no problem to slip it out(i havent powered anythin on yet). i have everything soldered correctly, ijust need a correct op amp now
Aha now i understand what's confusing you :bigeyes: . The number on the wires on the scheme i posted isn't correct!! They are made up by my simulator so you can forget about them. Vcc is pin 8 and here goes +12V, Gnd is 4 and so on like in the datasheet you posted. Notice also that the NE5532 is a dual opamp in one packade so you don't mix'em together. Once again, im sorry i confused you :xeye:

About C3:
In a number of ELFA ( they suggest this configuration of a mic preamp with this polarity. I have build this mic preamp and tried it with the cap in the other direction and for some reason it didn't work. So i believe everything is in order. If you have any other experience from real life building of this little amp please post.
Yeah, I knew that this was an old thread, but was hoping someone could shed some light on it for me. I just need to know that If I need to build 2 seperate circuits, using 1 of the NE5532 op-amps to do the trick. Oh and to make sure that if I remove R5, I won't cause any damage to the DVD player. Thanks!
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