Does this work to go between microphones and preamps that don't have phantom built-in? Regulated 48v DC supply.
3ch Phantom Power Supply Switcher
- Thread starter StarTrucker
- Start date
Help Support GroupDIY Audio Forum:
If you want it to be usable with any preamp without needing to know details of the pre-amp input circuit you should have DC blocking capacitors so that 48V is not applied to the input of the preamp, and you should have protection diodes. Typically protection diodes would dump fault currents into the power supply rails of the preamp, but in an external phantom power supply the only thing you could do is have some kind of voltage clamp, like a transient suppression diode (essentially a high current zener style device).
So
1. dc blocking caps between input and output
2. a zener in line with the +48v after the switch and before the resistors.
1. dc blocking caps between input and output
2. a zener in line with the +48v after the switch and before the resistors.
Yes.
No, something like the figure 24 from "The 48V Phantom Menace Returns" paper from a few years back.
Looks like ThatCorp fixed their website problems, it is available again here.
Something like this, but I would probably use lower than 18V TVS in this application, that was chosen in the context of using a That pre-amp chip which was probably powered from 15V, but could take up to 20V max on the power pins, so 18V TVS would not get triggered by the 15V supplies, but would turn on before hitting the chip max voltage rating.
