I've bought a condenser studio microphone that connects to my computer.

It looks like this:

enter image description here

Unluckly it's too quiet and actually can't make any recording without boosting it's sensitivity in Windows (but the audio will suck.) I designed a pre amp for it.

The problem is I actually don't know how to connect the microphone to the amp then to my PC.

On the bottom of my microphone there is a 3 pin XLR connector, but the microphone came with an adaptor cable that transforms that XLR conector into a 3.5 mm jack.

The only thing I know is that pin 1 and 3 of the XLR connector are connected together through the adaptor cable to the sleeve of the 3.5 mm jack and pin 2 of the XLR is connected to the ring and tip of the 3.5 mm jack

I'd like to know how I would connect my microphone to the pre amp and the pre amp to my computer.

I've also added a schematic of my pre amp.

pre amp

  • 2
    \$\begingroup\$ 1. Your microphone requires a DC input. This is commonly called "phantom power." It works (poorly) on the 5V supplied to it through the microphone jack on your PC. It is designed to operate on 48 V phantom power. The best solution would be to use a proper 48V power supply made for XLR microphones. \$\endgroup\$
    – JRE
    Aug 26, 2020 at 5:30
  • \$\begingroup\$ 2. Your microphone requires as DC input. Your pre amplifier circuit doesn't supply power to the microphone. The microphone will not work without the DC supply. \$\endgroup\$
    – JRE
    Aug 26, 2020 at 5:31
  • \$\begingroup\$ This is quite nice and far far far less complicated. Plug and play USB communications with your PC, easy to set microphone knobs (two of them) and a separate headphone jack that works nice, as well. It's simple as it gets. If you were a professional with specialized requirements for XLR microphones, that would be one thing. But at US$25 on Amazon, that's not the case. You'll be needing expensive extra hardware for it. May as well skip the difficulties -- my opinion, anyway -- and get working without trouble using something else. \$\endgroup\$
    – jonk
    Aug 26, 2020 at 5:46
  • \$\begingroup\$ I use the same microphone with shock absorber, plugged into my Dell Workstation with the 3.5mm jack. I use Audacity (free download) to boost audio levels. Works great, but workstations often have custom audio and video hardware most PCs do not have. I have a 1394 Firewire port, meant for HDTV cameras. Audacity alone may solve gain problems. Phantom power is another issue. My PC supplies this. \$\endgroup\$
    – user105652
    Aug 26, 2020 at 8:21

1 Answer 1


First some quick googleing:


the german wikipedia has a nicer diagram: [https://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/P48a.png/300px-P48a.png][2] from [https://de.wikipedia.org/wiki/Phantomspeisung][3]


OK its in German: Schirm=shield, Kabel=cable, the other words in the diagram are self explanatory, first example is mixer with no phantom voltage and second is mixer with phantom voltage support...

And here comes your problem! your PC has no phantom voltage support, so so can't directly connect the mic with 48V DC on the signal wires to the PC. you need some galvanic isolation. Your PC is like a mixer without phantom voltage support.

You can buy things like this: [https://www.amazon.de/Neewer-Leistungversorgung-Kondensor-Ausr%C3%BCstung-Musikaufnahmemittel/dp/B019JWZCOS/ref=sr_1_2?__mk_de_DE=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=H68I1CKDM3WY&dchild=1&keywords=phantom+speise+adapter&qid=1598427186&quartzVehicle=705-1359&replacementKeywords=speise+adapter&sprefix=phantom+s%2Caps%2C199&sr=8-2][5]

Guess a self build box with all parts isn't any cheeper.

Warning: some sites state 12-48V and state some microphones will die if the voltage is too high, so read your mic's tech. data first.


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