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I'm going to connect an electret mic (WM-61A) to my computer's "mic in", and am very confused on the reasoning behind a couple different diagrams/schematics that could possibly be used to do this with. The first one is from a thread on Head-Fi and seems to be the standard that everyone uses there: enter image description here This is good to me, but then when I did a search for a couple different options, I found this: enter image description here There's also another schematic using an AD654 op-amp specifically for phantom power. The one above claims to provide a "Phantom Ground"; what exactly is this compared to the first schematic and compared to a virtual ground? Could any of these be used for my purpose?

Please and thank you for any guidance given!

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The extra circuits you have researched do not apply if all you are trying to do is interface an electret microphone to a computer mic-in port.

Those extra circuits produce a mid-rail voltage (such as 4.5 volts when using a 9 volt battery) and are useful when developing an op-amp amplifier circuit and all you have is a single power supply such as a 9 volt battery. The mid-rail voltage can be regarded as ground for any audio inputs or outputs. It is sometimes called "phantom" or "virtual" ground but I prefer the term "midrail generator" because it says what it does. You don't need this for what you are wanting to do.

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  • \$\begingroup\$ That's exactly what I needed to know. I figured they weren't the same as they looked to make a virtual ground, or else called "midrail generator" like you said. I have a better understanding now, so thank you very much! \$\endgroup\$ – topher Dec 28 '16 at 15:17
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    \$\begingroup\$ Currency of thanks is upvoting or formal acceptance of an answer but leave it a day to see if any new answers come along that might be better. \$\endgroup\$ – Andy aka Dec 28 '16 at 15:36

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