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I have a generic handheld dynamic microphone and I want to connect it to my laptop for voice chatting. Normally it should connect to an mic amp and then goes to soundcard's line-in jack.

But my laptop only have a mic jack. Also I've heard that there is a bias voltage around 5V in the mic jack, and the pin definition may vary for different soundcard. After sometime of research I come up with this convert cable. Will it work? If not, what should I do? Is mic amp a must?

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  • \$\begingroup\$ an amp is a must, but a lot of soundcards have it built in. \$\endgroup\$
    – PlasmaHH
    Commented Dec 19, 2017 at 13:55
  • \$\begingroup\$ An exact, one letter accurate type of your laptop would be useful. Without it all answers are guesses or have only general things. \$\endgroup\$
    – user136077
    Commented Dec 19, 2017 at 13:55
  • \$\begingroup\$ @user287001 For my laptop (Lenovo T430s) it's ALC3202 made by Realtek. \$\endgroup\$
    – whc2001
    Commented Dec 19, 2017 at 13:57
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    \$\begingroup\$ @whc2001: You don't seem to have any DC path through your microphone, so I don't see what you want to avoid. \$\endgroup\$
    – PlasmaHH
    Commented Dec 19, 2017 at 14:28
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    \$\begingroup\$ @whc2001: Since on insert the normal 3.5mm will short circuit stuff usually too I am sure whatever provides the bias voltage will be able to deal with that \$\endgroup\$
    – PlasmaHH
    Commented Dec 19, 2017 at 15:33

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Exact schematics are not generally available. I have instead tested other audio mic inputs. DC for mic exists. It is not disconnectable nor adjustable from the Windows Realtek HD Audio user interface. Probably it's adjustable and disconnectable with some utility software, but I haven't met such thing. The DC +3V was connected via at least 6kOhm resistors to tip and ring (=3 and 4) of the 3,5mm plug. There's no DC between 3 and 4. It's only 4 to 2 and 3 to 2.

This is a low voltage version of phantom mic supplying system. I am sure that max. possible 1 mA DC current through a dynamic mic do not cause harm, if you leave the capacitors out and connect one wire of your mic to tip and ring and the other wire to the ground (2). I have done it without realizing there's DC.

Your connection with capacitors should work. It makes sure that the mic does not get DC magnetization. Have high enough capacitances to avoid losing the bass. Remember the right polarity for electrolytics.

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  • \$\begingroup\$ Thanks for the information and tip. I firstly used 104(0.1uF) ceramic disks and realized the sound quality is bad. After swapped to 10uF electrolytics it worked like a charm. \$\endgroup\$
    – whc2001
    Commented Dec 20, 2017 at 16:07

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