• Registered: 2020-09-12
  • Posts: 5

Topic: Fireface TRS outputs handling phantom power?

Hello,

I'm using a Fireface 400 for a live show. Sometimes, while we are patching on stage, sound technicians offer to plug straight to the interface a TRS multi cable and therefore save the use of several DIs.

I know the Fireface 400 provides symmetrical outputs so I'm totally up for it. The thing is, when setting up a stage there is always at one point someone making a mistake, recalling a digital console template, faulty cable, etc... so I'm afraid my interface would accidentally receive phantom power straight to its jack outputs and feel safer using DIs.

Is phantom power harmless on a correctly wired TRS jack? And on a wrongly wired one?
Am I too cautious?

Thanks for your help & opinion :)

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,693

Re: Fireface TRS outputs handling phantom power?

Better not - its best to avoid continous exposure...


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

3 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,438

Re: Fireface TRS outputs handling phantom power?

Phantom power at the interface outputs is indeed a real (live) problem. The FF400 has electrolytic capacitors at the outputs that get invers charged by phantom power, and consequently destroyed after some time.

In later units (UFX) those caps were therefore reversed in polarity, and in latest units (UFX II) we don't use such caps anymore. Those two schemes have no problem with phantom power arriving at the 'wrong' port.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2020-09-12
  • Posts: 5

Re: Fireface TRS outputs handling phantom power?

Thanks a lot for those answers, I'll keep on insisting we use DIs then, as we've done so far.
Best,
Clément