Condenser Microphone Pre-Amplifier 48V phamtom power supply

[electrovanga]

Hello,
I am designing a preamp. I will use Focusrite Scarlett audio interface.
I have two questions.
1. Can I connect 48V to out+ in the schematic?
2. How do professional microphone manufacturers provide 48V on their PCB?

[wasedadoc]

Have you done any research on how phantom powering works?

[electrovanga]

Hi,
Yes, I did but I couldn't be sure wheather I can get this 48 volt from pin nuber 2 or 3.

[themadhippy]

but I couldn't be sure wheather I can get this 48 volt from pin nuber 2 or 3.

phantom + is normally on both

[wasedadoc]

Hi,
Yes, I did but I couldn't be sure wheather I can get this 48 volt from pin nuber 2 or 3.

So you have not yet understood phantom. 

[electrovanga]

I think I watched all the videos possible and read so many articles on the websites. However, I couldn't understand or be sure. Maybe, it is because of my fundamentals.

[coppice]

Phantom power is not well defined. The impedance varies, and the voltage is sometimes 24V instead of 48V.

[wasedadoc]

Where is your preamp to be located? At the mic capsule or in the mixing desk etc? The former has phantom power fed to it. The latter feeds phsntom power out.

Phantoms typically employ a centre tapped audio transformer. Power runs equally in same direction through the two balanced audio wires and returns via the third wire.

How can you be designing a preamp without understanding these basics?

[boB]

This looks right but do not forget the XLR pin 1 for power return

[electrovanga]

Thanks for the all answers. I will try to answer all.

My preamp will be inside of the microphone. I am tryin' to learn. I want to do more hands-on projects to see the real life. I will first simulate and then print the PCB.


The phantom power comes from scarlett. It is P48.

I understand that if I take the 48V from XLR's 2.pin for FDOpamps' positive and 3.pin for FDO's negative, then that circuit will work. I hope I understand it right.
I will connect the earthing to XLR's 1.pin. This will be the RF caps. I will also put small ceramic caps between 1-2 and 1-3.

[wasedadoc]

I understand that if I take the 48V from XLR's 2.pin for FDOpamps' positive and 3.pin for FDO's negative, then that circuit will work. I hope I understand it right.
I will connect the earthing to XLR's 1.pin.

Wrong.
https://www.prosoundweb.com/a-primer-on-phantom-power-for-condenser-microphones/
https://www.dpamicrophones.com/mic-university/know-the-basics-about-phantom-power

And you should be taking +ve equally from two wires.