Hi guys anyone knows how can i get 9v from a 48v phamtom power? Thanks in advance.
You could string together several zeners to get the drop you need, or you could use an LM317T regulator configured for 9v output, it would be operating right under the max 40v differential between input and output voltage.
You'll have to be careful about current draw. Phantom sources are fed through 6k81 resistors and limit the max current to 7mA per signal line. Using both hot and cold lines you only get 14mA, and that's into a dead short with the resistors dropping all of the voltage. If you're only drawing a couple of mAs, you're probably fine, any more and most of the voltage will be dropped across those internal resistors.
Thanks Scott, this means that it is difficult power several pedals through the Phantom Power? ???
Like we use charge pumps to boost voltage, dc-dc converters are also used to drop voltage with really high efficiency. A quick google gave me this solution from linear. I'm sure some investigation could get you where you need to be.
(http://cds.linear.com/images/product/4610_app_1.jpg)
Quote from: Guitafuzz on November 21, 2012, 05:14:03 PM
Thanks Scott, this means that it is difficult power several pedals through the Phantom Power? ???
Exactly. If it weren't for those resistors, you could use up to the phantom supply's max current, probably on the order of 200-500 mA.