In addition, the shared ground between unbalanced channels is blamed for crosstalk. These currents can introduce undesirable audible hum or other interference in unbalanced connections. Because the ground is linked, wayward currents from power supply transformer leakages or stray capacitance can become part of the audio signal. Drawbacks of Unbalanced ConnectionsĪ possible negative side effect of an unbalanced connection (line level or headphone) is the potential for unwanted noise, interference or hum to be introduced to the signal. This is known as a TRS (Tip, Ring, Sleeve) connector. The most common type of headphone connector is unbalanced and has three contacts for the L+, R+ and shared. The ubiquitous standard unbalanced TRS headphone jack in 3.5mm (⅛”) and 6.35mm (¼”). These individual grounds are joined at the plug connector.
3.5 MM GROUND DRIVER
However, most headphones of decent quality do have a separate wire from each negative terminal of the headphone driver through the length of the cable. In an unbalanced headphone setup, the ground connections for both sides are often tied together, so it is possible that the headphone cable may only consist of 3 wires: L, R and shared ground. Because the impedance to ground differs, we call the connection unbalanced. Unbalanced connections derive their name from the relative impedance to ground of the two connections in each channel: hot or positive ‘+’ and ground or negative ‘-’. It works the same way for line-level connections between components. Each pair of wires provides a voltage reference it is the difference between these references that drives our headphones. For a pair of headphones, there are two wires connected to each channel: left ‘L’ and right ‘R’.
This loop connects the audio source and the load (headphone driver). In the simplest terms, transferring an audio signal to a single headphone driver requires a pair of wires to create a loop. Fully balanced internal circuitry has been promoted as yielding 3 dB better dynamic range, though at increased cost over single-ended designs.” – Wikipedia Unbalanced Connections
Usually when you see the phrase “balanced amplifier” it is referring to a differential amplifier without shared grounds and balanced outputs. Balanced and unbalanced are types of interconnections between devices these terms do not refer to specific amplifier architectures. Balanced Amplifiers or SourcesĪs explained earlier, the term “balanced amplifier” is something of a misnomer. In this article we will discuss the technology behind balanced and unbalanced connections and if it makes an appreciable improvement, or even a difference, in sound quality. The industry would like to equate balanced connections with expensive, high-end, and ultimate fidelity, however, this isn’t necessarily the case. Certainly, balanced line-level connections normally only appear on higher end gear. Whether you encounter these connections depends on the complexity of your personal setup and whether the source, DAC, and amp all are contained within one integrated device or are connected via external cables. The higher signal levels can improve the SNR (signal to noise ratio) of the audio system.” – Benchmark Media Systems Balanced line-level interfaces reject hum and noise while providing a higher voltage level. “In these box-to-box line-level connections, a balanced interface can provide substantial performance improvements. The phases (positive and negative or hot and cold) are the two important voltage references for differential amplification.
Differential amplification can achieve higher power and greater efficiency than single-ended amplification (given the same parts).Ī differential amplifier only cares about the difference between phases, so non-linearities, power supply ripple, and interference tend to cancel once the phases are recombined. A differential amplifier has pairs of devices, with each half of a pair amplifying opposite phases of the signal. The other basic amplifying structure is referred to as differential (or push-pull). In this type of circuit structure, we usually have two important voltage references: the signal itself and ground. In a single-ended amplifier, the signal always remains whole and is handled in its entirety by the amplifying devices (tubes or transistors). One basic amplifier circuit structure is referred to as single-ended. All amplifiers follow one of two basic circuit structures related to how they treat signals and grounds: single-ended or differential.
0 kommentar(er)
