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HarmonicTHD
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Maybe a short explanation to balanced. Balanced for headphones is pretty much an audiophile gimmick. Balanced is used in long runs (tens of meters and more) of signal cable especially in electrically noisy environments where it provides noise rejection. For the 1 or something meter of headphone cable balanced makes no sense whatsoever.
Roland68
Major Contributor
Please don't be angry if I correct you, but that is absolutely wrong and especially confusing to beginners.
Balanced for headphones consists of two amplifiers for each side separately, without connection to the device ground. This results in twice the power, which isn't necessarily stupid, but it can also increase the noise since it's the sum of two amplifiers.
This has nothing to do with the XLR connections from the pro audio range, where the interfering interference is eliminated by offsetting the anti-phase signals with each other.
But only if it’s the same amps. And the most gain will probably be with high impedance headphones that need voltage, not current. The op has low impedance headphones.
In any case, you can design a non balanced amp to have the same power and performance just as well.
TurtlePaul
Addicted to Fun and Learning
No. Balanced headphone cables are snake oil. Single ended cables can easily achieve audibly perfect performance, noise rejection doesn’t matter for headphones like it does for microphones with long cables and ground loops can’t be caused by headphones because they are not grounded. Those are the reasons for balanced cables with other equipment and they don’t apply. Plenty of single ended (three pin) headphone amps can get to transparent levels of cross-talk immunity. A bunch of amps with ‘balanced’ four-pin outputs are really just single ended internally.
Though there is a case for improved separation with balanced.
With unbalanced, each ear piece shares the return wire. Which means the return currents from one ear piece through the return wire impdeance will cause a voltage applied to the other ear piece.
Whether this is audible even with long cables is another matter. I have no data for that. Though I'd suspect it might be with low impedance headphones, and long cables.
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TurtlePaul
Addicted to Fun and Learning
…
No. You need data. Amir has measured a ton of headphone amps. Plenty of amps have crosstalk in the inaudible range. Because of auditory masking, crosstalk is almost impossible to perceive.
But measuring crosstalk in an amp tells us nothing about the impact of shared return path in unbalanced headphone cables.
Here is Benchmarks take: They don't provided balanced amplifiers but they do provide a 4 wire connection to give separate return paths.
Sadly no measurements are referenced:
Audio Myth - Balanced Headphone Amplifiers are Better
This Myth Goes Something Like This: "Balanced headphone amplifiers are better." "If balanced line-level connections work well, balanced headphone outputs should also work well." We disagree! Benchmark does not offer voltage-balanced headphone outputs on any of its products. The reason for this...
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TurtlePaul
Addicted to Fun and Learning
The crosstalk should be dominated by the headphone amps output impedance rather than the minuscule cable impedance of the ground channel.
Most IEM cables measure about 0.2 ohms vs. loads of 20 ohms or more and amp output impedances which can be much higher than the cable.
The amp output impedance isn't shared by the two drivers, like the shared return path is. For the purposes of this discussion, I think the amp output impedance is irrelevant.
In your example 0.2ohm shared return compared to 20ohm load is 100:1 or potentially crosstalk at 1% (-40db)
But a low impedance headphone might be lower than 10ohm (eg Verum Audio Verum 1 at 6.6ohm) bringing the cross talk to -30dB with 0.2ohm in the return path.
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