Understanding the Difference Between Balanced and Unbalanced Phono Jacks
The primary difference between balanced and unbalanced phono jacks lies in how they transmit audio signals and their susceptibility to noise and interference. Both types are crucial in various audio applications, with unbalanced jacks being more common in consumer audio equipment, while balanced jacks are preferred in professional settings due to their superior noise immunity.
Unbalanced Phono Jacks
Connection Type
Unbalanced phono jacks typically have two connections: a tip signal and a sleeve ground.
Signal Transmission
The signal is carried on a single conductor with the ground acting as the return path.
Noise Susceptibility
These jacks are more prone to picking up electromagnetic interference (EMI) and radio frequency interference (RFI), as the signal and ground share the same path.
Typical Use
Unbalanced jacks are commonly found in consumer audio equipment such as guitars and home audio systems.
Balanced Phono Jacks
Connection Type
Balanced phono jacks have three connections: tip positive signal, ring negative signal, and sleeve ground.
Signal Transmission
These jacks use two conductors to carry the same audio signal but one is inverted 180 degrees out of phase. At the receiving end, these signals are combined, which cancels out any noise picked up along the cable.
Noise Resistance
Balanced jacks are much more resistant to noise and interference, making them ideal for professional audio applications.
Typical Use
Balanced jacks are commonly found in professional audio equipment such as mixers, microphones, and studio gear.
Factors Affecting Sound Quality in Audio Systems
The audio cables, including jacks, have a significant impact on the sound quality in any sound system. These two parameters have the capability to eliminate Noise or Distortions from the sound signal.
Where Does The Noise or Distortions Come From?
Noise can come from a variety of electrical and radio interference, but it most commonly comes from power cables which can create a humming sound if they are near cables carrying unbalanced audio. Older non-LED stage lighting for example spotlights or dimmers can also add signal interference.
Unbalanced Audio
An audio cable carrying an unbalanced signal uses two wires: a signal and a ground. The ground wire acts as a reference point for the signal but also acts like an antenna, picking up unwanted noise along the way.
The best technique for reducing noise when using unbalanced cables is to be careful with cable placement. A single perpendicular crossing of power and audio cables is much better than a parallel run. If parallel cannot be avoided, leave as much space as possible between audio and power cables.
Unbalanced Cable Type Example
Examples of unbalanced cables include RCA cables and quarter-inch TS cables.
Balanced Audio
The structure of a balanced audio cable is similar to an unbalanced cable—except it carries two copies of the same incoming audio signal, referred to as a “hot” positive and “cold” negative signal.
These signals are reversed in polarity as they travel down the cable, canceling each other out. At the receiving end, the cold signal gets flipped in polarity to match the hot signal, causing the noise added to both cables to cancel out.
Because balanced signals send two “in-phase” signals, they are also louder, roughly 6 to 10 dB, than what unbalanced signals can provide.
Some devices offer both options, such as the newly launched Sony DMP-Z1 Digital Music Player Signature Series, which has both Balanced and Unbalanced jacks.
Benefits of Balanced Cables
Compared to unbalanced cables, balanced cables are a significant improvement because they have a better signal-to-noise ratio, much lower impedance signals, and are less susceptible to external noise or distortion. They also provide a more reliable signal that is stronger over long distances.
Conclusion
In conclusion, understanding the differences between balanced and unbalanced phono jacks can help you choose the right audio cable for your specific application, whether it's for professional or consumer use. The choice between the two depends on the necessity of reduced noise and interference, as well as the required signal strength and distance.