Is 28V Phantom Power acceptable?

  • Thread starter Thread starter pchorman
  • Start date Start date
testing phantom

what's the best way to test my phantom output? I'm assuming i can put my multimeter leads to the other end of a connected mic cable. What should I look for? 48V across pin which to which?

Thanks for the help.

-Doug
 
48V between pin 2 and pin 1, and pin 3 and pin 1.

As far as modifying the phantom power supplies: P48 phantom is defined as "48V with respect to pin 1 applied to pins 2 and 3 via a pair of matched 5.6Kohm resistors". The resistor values need to be matched to tight tolerance (1% is best) to prevent any addition of DC offsets to the mic signal, or imbalance currents that cause partial saturation of any transformers in the mic or preamp circuitry.

So if you can manufacture a clean 48VDC somehow inside the box, you certainly can modify the phantom circuit. The problem is usually getting the 48V rail- if you have 12V, you can make a voltage quadrupler easily enough. Other voltages require more circuitry...
 
Last edited:
skippy said:
48V between pin 2 and pin 1, and pin 3 and pin 1.
Click to expand...

both voltages should measure exactly identical! This is even more important than the exact voltage itself
 
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