Question: How do I determine if the TRS 1/4" connection is balanced or stereo?

Answer: It is important to know how to properly interconnect audio devices. Some audio devices use a 1/4" TRS (tip-ring-sleeve) plug that is wired in a stereo configuration where the left audio channel is connected to the tip, the right audio channel is connected to the ring, and the ground is connected to the sleeve. Alternatively, other audio devices may use the same 1/4" TRS connector but wired in a balanced audio configuration. The way these two configurations are designed, interchanging them may cause issues and impede the audio signal performance. Not all connections are equal. Make certain you confirm each device’s specifications to ensure the proper wiring configuration.

A balanced audio connection uses three conductors and is commonly used with XLR connections. There are, however, other multi-conductor connections, such as a 1/4" (6.3 mm) and 1/8" (3.5 mm), that are used for balanced audio. The balanced audio circuit was designed to reduce noise that is picked up over long cable runs. An unbalanced cable uses two conductors and includes the audio signal and the ground. Even though the cables are insulated and shielded, noise and hum may be introduced into these cables. Balanced audio was designed to counter this issue by including the same audio signal on another conductor with equal impedance, but with inverted polarity. The two conductors carrying the audio are twisted inside the cable insulator, which is why this is commonly referred to as a “twisted pair.”

The balanced circuit in the device that is sending the signal will send the positive audio signal (aka “audio +” or “hot”) as well as the negative audio signal (aka “audio -“ or “cold”) and the ground over the three-conductor cable. The balanced circuit in the receiving device will take the two audio signals (both audio + and audio -) and, with its differential amplifier, cancel out any differences between the two signals. Remember, noise and interference will be picked up by any cable in both audio channels. The differential amp will remove the noise that was picked up, resulting in a clean audio signal without the noise.

When you are connecting audio devices together, pay close attention to how they are wired. Following the information outlined above, if you connect a stereo signal consisting of two independent and different audio signals to a balanced circuit, you will cancel out the audio signal. This is due to the design of the differential amp reversing the polarity of the second audio signal.

Please contact the Audio Solutions Department if you have further questions on stereo or balanced audio circuits.