Can Phantom Power Pass Through TRS? Here’s The Truth


Certain recording devices, such as condenser microphones, rely on the extra voltage provided by phantom power to operate successfully. These devices commonly use 3-pin XLR cables. 

Can phantom power pass through TRS?

Phantom power is not exclusive to XLR cables and can pass through TRS. Therefore, when it is turned on, +48v (Phantom Power) is running to all of the selected microphone inputs. TRS cables are commonly used for line-level instruments, but they can still transmit phantom power if required. 

However, this doesn’t mean that using a TRS cable with phantom power won’t produce some issues.

Usually, the preferred cable for connecting microphones or other devices that require phantom power is a 3-pin XLR. These cables are optimally designed to facilitate phantom power.

TRS cables, on the other hand, are likely to run into some problems when used for this purpose, which I’ll discuss in detail in this guide. 

Phantom Power & Cables

If you have used microphones for recording audio or live performances, you’ve likely come across phantom power before. It’s usually presented in the form of a small button or switch on an audio interface, mixer, or preamp. 

The vast majority of condenser microphones require phantom power to function. Without it, the microphone is incapable of recording or projecting audio – all that you’ll be left with is a silent waveform in your chosen DAW. 

The traditional cable that is used with condenser microphones is the XLR.

This cable is specifically designed to facilitate phantom power and has all of the necessary qualities required for recording and live sound purposes. XLRs are durable, reliable, and can stretch long distances without compromising on sound quality. 

TRS cables, on the other hand, are less commonly used for this purpose.

Brilliant creations in their own right, TRS cables are defined by their distinctive design – with a tip, ring, and sleeve connector. This contrasts the 3-pin design of XLR cables, and the difference is significant. 

For phantom power to successfully pass through the TRS cable, you’d need to take some additional measures.

This would include converting the signal back to XLR, which is possible but a little tricky initially. I’ll cover that in detail later in this post. 

XLR cables are capable of having phantom power pass through them without needing to covert the signal or make any alterations to the cable whatsoever. This is because of the design of their connectors. 

To understand why phantom power finds it much easier to pass through an XLR compared to TRS, we must inspect the differences between the two cable types.

Phantom power and XLRs are exclusive to one another, but it just so happens that they form a highly compatible partnership. 

TRS vs. XLR

Although most phantom power supplies, whether it is an audio interface, mixer, or preamp device, send +48v phantom power through balanced XLR connections, this doesn’t mean that an XLR is the only option.

Specific types of TRS cables are commonly used with phantom power passing through them in recording studios. 

  • The deciding factor here is whether the TRS cable is balanced or unbalanced.

All XLR cables are balanced by nature, which explains why they are commonly used to supply phantom power to condenser microphones.  

TRS cables are slightly more complex than their XLR equivalents.

They can be either balanced or unbalanced, depending on the output and input that both sides of the cable are connected to. For example, if you connect a TRS-A cable between a balanced TRS output and a balanced TRS input, it will perform the role of a balanced cable. 

The confusion surrounding the use of TRS cables with phantom power stems from their versatility.

They are commonly used for carrying mono signals, such as line-level instruments like guitars or bass. We don’t associate phantom power with line-level instruments, and therefore many people aren’t aware that it can pass through TRS. 

Nevertheless, there are particular instances where TRS cables are used with phantom power. One of the most common is in a recording studio when a patch bay is created. This is a rare scenario where non-XLR cables are used for this purpose. 

Unlike the conventional method of using an XLR cable, when patch bays are used, the TRS cables are unlikely to be plugged directly into a phantom power source, or a microphone. In most cases, the patch cables are used to route other devices, passing audio and phantom power from one device to another. 

XLR/TRS patch bays are quite common in recording studios, and most of the time, they’re safe for powered microphones that require +48v phantom power. However, it’s quite easy to set up the patch bay incorrectly, which makes damaging the equipment a potential reality. 

Check out this video on patch bays for more information.

If the XLR and TRS cables are wired in parallel, this means the patch bay is safe for balanced line-level inputs using either type of cable. In contrast, it is not safe to use this method with phantom-powered input microphones. 

Connecting or removing the TRS cable to or from the patch bay will cause what is known as an unbalanced electrical short.

Any phantom-powered microphone input that is wired into the patch bay will be subjected to the unbalanced short, which can easily cause damage to the microphone input, and any dynamic or ribbon mics that are connected at that moment. 

Providing the correct measures are taken when setting up a patch bay, the phantom power passing through the TRS cable can be made safer.

This involves using independent connections for both the XLR and TRS connectors. This means that only the mic lines are used with the relevant XLRs, and any line-level inputs are being used with the TRS cables. 

  • Fundamentally, it’s best to avoid passing phantom power through TRS cables wherever possible.

Although the aforementioned method is considered to be safe and effective, it’s a lot more hassle than simply using XLR cables for any devices that require +48 volts and using TRS cables for line-level instruments or devices. 

When phantom-powered microphone inputs are connected to TRS patch bays, or simply passed through TRS cables, the risks are generally not worth it.

For the price of a suitable XLR cable, it’s worth investing in to protect more expensive equipment like dynamic and ribbon microphones, or instruments like keyboards. 

The table below highlights the recommended cables for popular music and audio devices.

Device/Instrument Balanced/Line-Level Preferred Cable
Condenser Microphone Balanced XLR
Ribbon Microphone Balanced XLR
Dynamic Microphone Balanced XLR
Electric Guitar  Line-Level TRS/TS Jack
Keyboard Line-Level TRS/TS Jack

Phantom Power & Connectors 

The main reason that phantom power sources utilize XLR rather than TRS cables is electrical shorting. This comes down to the design of the connectors on each cable. 

XLR connectors are designed with three pins.

The second and third audio pins are equally sized, while the first, which is also known as the ground pin, is a little longer. This may seem like an insignificant detail, but it makes all of the difference when it comes to phantom power. 

When the XLR is connected, it is grounded before the phantom power circuit being completed. This is because the second and third pins are equal in length, and consequently, they connect to the source at the same time, with no shorting. 

When we compared this connection process to that of a TRS cable, it becomes clear that XLR is much better suited for use with phantom power. TRS connectors are designed sequentially, meaning each part connects at a different time. 

Firstly, the connector comes into contact with the sleeve of the TRS cable, followed by the ring, and then the tip of the jack. Finally, the ring of the plug hits the sleeve, forming the connection to the ring of the TRS jack. 

When the TRS cable is fully plugged in, the TRS jack forms a connection with the TRS of the input or output plug. The issue here is that whenever you physically insert or remove the TRS cable from the plug, an electrical short occurs. 

This electrical short is likely to result in the flow of phantom power becoming erratic. The result, in the worst-case scenario, can be irreparable damage to a microphone, particular ribbon mics, and sometimes dynamic mics. 

You can check out my article on ribbon microphones here.

Related Questions

Can condenser microphones be used without phantom power?

The vast majority of condenser microphones need +48v phantom power to function. With that being said, there are some alternative powering methods that some can be used with, including external power supplies, batteries, and DC-biasing. 

You can also get USB condenser microphones. Check out my article on USB condensers here.

Are TRS or TS jack cables better for line-level instruments? 

For plugging line-level instruments such as guitars, bass guitars, or keyboards into an amplifier or recording device, TS jack cables are recommended. Using a TRS cable for this purpose is likely to result in the signal strength and quality being compromised. 

Is TRS balanced or unbalanced? 

TRS cables are unique, in that they can function as both balanced and unbalanced. This depends on the devices that the cable is plugged into. They can be used for mono, balanced signals, and stereo signals too, making them a versatile cable. 

 

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