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I have a professional external sound card and a condenser mic. However I'm not a musician and I have not bought the equipment for the purpose music production as it is only for the purpose developing technical tutorials on software development.

My sound card has 48v phantom power and there are 4 XLR inputs in the front side and 4 in the back. The XLR inputs are all accepting TSR as well. Let's say that I'm not using the XLR input and I've connected something with a TSR plug (let's say my classic guitar) and the phantom power is on. Would the plug run 48v in the cable or does it only run only and only if a 3pin XLR is connected?

One more question, would the 48v phantom power cause electrocution?

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    Putting phantom power on TRS is a bad idea because of the order the contacts are made when you connect a TRS cable. Basically, the tip temporarily touches the sleeve and ring contacts when you plug it in, so all kinds of unpredictable stuff can happen if you have power on one of those. If your interface is a well known brand it almost certainly is not putting phantom power on the TRS contacts in the combo connectors. You could just ask the manufacturer to confirm via email or forum, assuming you've already checked the manual.
    – Todd Wilcox
    Jun 6, 2017 at 5:21

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It would be very unusual for equipment to put phantom power out to TRS inputs. One reason is that connecting an unbalanced TS connector would shorten one line with phantom power but not the other, resulting in a high bias voltage for whatever equipment. Another is that TRS sockets are forming connections almost nilly-willy when plugging in which makes them badly suited for carrying any kind of power or higher voltage.

48V is usually not enough for electrocution unless possibly you are in the habit of licking your microphone or urinating on it. Which is a bad idea due to grounding issues much more than with regard to phantom power.

Phantom power does not carry currents sufficient to cause burns but currents running through your heart do not need that level to become dangerous. However, helpers will be reasonably safe pulling you off whatever you managed to become a circuit of.

So in a nutshell: if you worry, keep company. But there is little enough to worry about even if you are working with low-budget hardware: it would be highly unlikely for phantom power to be in TRS sockets, highly unlikely for it to get exposed, and even then it will much more likely fry your microphone than yourself.

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Yes, if your phantom power switch is turned "on" then 48v is running to all mic inputs. However, phantom power is not dangerous to humans, only ribbon mics (if you have any). It might make a buzzing sound or mess up the audio in another way but it's not dangerous. A quick check of the manual can tell you which inputs are mic inputs.

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    Are you sure, it's would run on a TRS as well??
    – Transcendent
    May 22, 2017 at 15:03
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Mixers do not have phantom power on 1/4" plugs (which are not TRS by definition) - other devices have TRS that do. I use adapters of XLR to TRS all time - don't guess. Use a TRS-to-XLR adapter to find out. Usually we use XLR cables to connect microphones with phantom power. However, there is nothing special about the three wires in the cable, just the way they are used. As long as the pins are wired correctly (tip/ring/sleeve connected to the correct XLR pins according to specifications) then they can transmit 48v phantom power IF they are designed as mic level inputs.

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  • What do you mean 1/4" plugs are not TRS by definition? Are you just indicating that they may also be TS instead of TRS? Or are you getting at the fact they aren't balanced? The wording seems confusing. 1/4" plugs on mixers certainly can be TRS, which is just s description of the connector type, not the type of signal being used. Insert cables, stereo 1/4" inputs and balanced TRS inputs for mixers would all be TRS.
    – AJ Henderson ♦
    Jun 23, 2017 at 13:25
  • I think he means, phantom power (over any connector) is not TRS.
    – jpaugh
    Jun 23, 2017 at 14:36
  • The 1/4" male connector (TRS or TS) by definition has a 1/4" pole and will fit in the same size female connector. However, professional sound cards/recorders use 1/4" TRS plugs as line level connectors. BUT, in a well-labeled patch bay I've used them to carry analog stereo, analog balanced, S/PDIF, digital AES and even video signals at one time or another to save space.
    – macmac
    Jun 25, 2017 at 2:21

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