2405Views5Replies

Author Options:

how to convert from Phantom power 48 to about 9v? Answered

Hi does anybody know how to convert from a phantom power supply +48 to 9v to power a single circuit of a microphone pre-amp
like this one "http://circuitdiagram.net/simple-audio-pre-amplifier.html " ?    it is for an electret microphone .... thanks

Comments

The forums are retiring in 2021 and are now closed for new topics and comments.
0
Re-design
Re-design

9 years ago

You could use a resistor to get the voltage down below +40 then use an lm317 voltage regulator chip to regulate it to +9. Not the best way but certainly the cheapest and since the current demand will be small it should work.

0
maguilar7
maguilar7

Answer 9 years ago

ok i found this what do you think

from this site:
Voltage Divider Calculator

calculations show that 2 simple resistors as shown will work.

input = 48v
R1 = 450ohm
R2 = 100ohm
output = 8.7v

and well what kind or value should the caps be ???

voltagedivider.gif
0
thegeeke
thegeeke

Answer 9 years ago

It would probably work, but it's possible that you will get extra noise with this setup. (Phantom is very specific in the way it works to keep noise out of the line.

0
steveastrouk
steveastrouk

Answer 9 years ago

Add some filter caps.

0
thegeeke
thegeeke

Answer 9 years ago

Ya... that would help. I'm not used to using consumer equipment that uses 9v... so I've never really had this problem. :)