Wrote this for some place else but I guess it is just as relevant here. Probably be better to post it in the Wiki section, but it doesn't seem to be working right after the forum update. So here it is.
A ‘single-ended’ source is the kind of normal audio source with a 3.5mm or 6.35mm stereo socket. It has a left and right channel going to the headphone’s drivers and a ground channel going back to source to complete the circuit. In a single-ended circuit, only left and right channel carry active signal while the ground channel doesn’t (passive / zero volt). FIG 1 is a simple representation of how most single-ended setup looks like
The origin of balanced audio is really from pro-audio’s stage usage. In a pro-audio environment that usually involves a lot of different very powerful electronic equipment running on the same time, RF interference can easy cause a lot of noise to a single-ended circuit, especially when long transmitting cable is used (which acts more or less like an antenna). The idea of balanced audio is to generate an inverted signal from the left and right channel, thus resulting in Left+ (original left signal), Right+ (original right signal), Left- (inverted left signal) and Right-(inverted right single). When the two pair of signal are sent over distance, any extra signal that can’t be cancelled out by the opposite pair can be identified as noise caused by the RF interference and subsequently being eliminated to reproduce the clean left and right signals. However, the inherent benefit of driving headphone with balanced signal is not because of noise, as headphone generally doesn’t have nearly as long a cable as pro-audio usage and thus doesn’t pick up much interference, but because balanced audio has: (1) Double the slew rate when compared to single-ended circuit as the opposite (inverted) signals having a ‘push-pull’ like relationship when compared to single-ended circuit where left / right signals are sinking into the same zero volt ground channel. This results in better transient for balanced audio. (2) Better channel separation since balanced audio does not share a common ground channel (which in fact is not requited in balanced headphone setup). Some might think balanced output on the same source will always give double the driving power than single-ended output – this is however not always true, depends on how the source is designed. With the right design, it is possible that the single-ended output performs just as good as the balanced output. FIG 2 is a simple representation of how most balanced setup looks like.
FIG 3 shows how the Pentaconn 4.4mm connection can also be used to power a single-ended headphone even though the source has a balanced output. This will required both the source and headphone to be designed and wired correctly. Not all Pentaconn 4.4mm equipped balanced source can be utilized in such way and you should consult with the source’s manufacturer first.
FIG 4 shows how you can convert a balanced headphone with the right adapter to be used on a single-ended source. Basically the adapter will short the headphone’s Left- and Right- wires together to be used as ground channel and effective turns it into the same configuration as a single-ended headphone.
FIG 5 shows you instead an incorrect utilization of adapter to connect a single-ended headphone to a balanced source. While you can convert balanced headphone to single-ended configuration by adapter, you cannot convert single-ended headphone to balanced configuration by a simple adapter. You will need to rewire a single-ended headphone’s cable in order to create a separated path for the individual Left+, Right+, Left-, and Right- signal – and an adapter will not do that. What this kind of adapter does is to simply short circuit the Left- and Right- channel together. Unlike ground channel, which has zero volt, Left- and Right- are active channel and they will not cancel each other out. In the best case scenario where the source has built-in protection circuit, using this kind of incorrect adapter will only decrease the sound quality and performance of the whole setup, besides messing up the stereo image of the music. In the worst case scenario where the source does not have any built-in protection circuit, it is possible to permanently damage the source’s circuit. In other words, never try to connect a single-ended headphone to a balanced source (with the only exception of what shown in FIG 3). Sometime you will find people selling this kind of adapter on ebay, Taobao or Aliexpress – do not get fooled!
A ‘single-ended’ source is the kind of normal audio source with a 3.5mm or 6.35mm stereo socket. It has a left and right channel going to the headphone’s drivers and a ground channel going back to source to complete the circuit. In a single-ended circuit, only left and right channel carry active signal while the ground channel doesn’t (passive / zero volt). FIG 1 is a simple representation of how most single-ended setup looks like
The origin of balanced audio is really from pro-audio’s stage usage. In a pro-audio environment that usually involves a lot of different very powerful electronic equipment running on the same time, RF interference can easy cause a lot of noise to a single-ended circuit, especially when long transmitting cable is used (which acts more or less like an antenna). The idea of balanced audio is to generate an inverted signal from the left and right channel, thus resulting in Left+ (original left signal), Right+ (original right signal), Left- (inverted left signal) and Right-(inverted right single). When the two pair of signal are sent over distance, any extra signal that can’t be cancelled out by the opposite pair can be identified as noise caused by the RF interference and subsequently being eliminated to reproduce the clean left and right signals. However, the inherent benefit of driving headphone with balanced signal is not because of noise, as headphone generally doesn’t have nearly as long a cable as pro-audio usage and thus doesn’t pick up much interference, but because balanced audio has: (1) Double the slew rate when compared to single-ended circuit as the opposite (inverted) signals having a ‘push-pull’ like relationship when compared to single-ended circuit where left / right signals are sinking into the same zero volt ground channel. This results in better transient for balanced audio. (2) Better channel separation since balanced audio does not share a common ground channel (which in fact is not requited in balanced headphone setup). Some might think balanced output on the same source will always give double the driving power than single-ended output – this is however not always true, depends on how the source is designed. With the right design, it is possible that the single-ended output performs just as good as the balanced output. FIG 2 is a simple representation of how most balanced setup looks like.
FIG 3 shows how the Pentaconn 4.4mm connection can also be used to power a single-ended headphone even though the source has a balanced output. This will required both the source and headphone to be designed and wired correctly. Not all Pentaconn 4.4mm equipped balanced source can be utilized in such way and you should consult with the source’s manufacturer first.
FIG 4 shows how you can convert a balanced headphone with the right adapter to be used on a single-ended source. Basically the adapter will short the headphone’s Left- and Right- wires together to be used as ground channel and effective turns it into the same configuration as a single-ended headphone.
FIG 5 shows you instead an incorrect utilization of adapter to connect a single-ended headphone to a balanced source. While you can convert balanced headphone to single-ended configuration by adapter, you cannot convert single-ended headphone to balanced configuration by a simple adapter. You will need to rewire a single-ended headphone’s cable in order to create a separated path for the individual Left+, Right+, Left-, and Right- signal – and an adapter will not do that. What this kind of adapter does is to simply short circuit the Left- and Right- channel together. Unlike ground channel, which has zero volt, Left- and Right- are active channel and they will not cancel each other out. In the best case scenario where the source has built-in protection circuit, using this kind of incorrect adapter will only decrease the sound quality and performance of the whole setup, besides messing up the stereo image of the music. In the worst case scenario where the source does not have any built-in protection circuit, it is possible to permanently damage the source’s circuit. In other words, never try to connect a single-ended headphone to a balanced source (with the only exception of what shown in FIG 3). Sometime you will find people selling this kind of adapter on ebay, Taobao or Aliexpress – do not get fooled!
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