balanced vs SE
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published: Nov-18-2025
Balanced versus single ended… what’s up with that ?
In audio when we speak of ‘balanced interconnects’ we actually speak of ‘differential signalling’.
The word ‘balanced’ is also used in a different way namely as balanced sound signature (tonality as in ‘realistic’) and has nothing to do with balanced connections.
There is a technical difference between ‘balanced’ and ‘differential’.
A connection can be differential but not balanced and single-ended connections can be balanced.
That’s confusing is it not ?
With ‘balanced’ is usually meant a ‘differential signal’ but when a connection is truly balanced also input, cable and output impedance are matched.
Matching output, input and cable impedance is important for RF (radio frequency) and digital connections but is NOT a thing for analog audio signal connections.
Analog audio connections can be differential and not also balanced but we call such connections ‘balanced’.
Balanced is not exclusive to RF/digital connections but can also apply to single ended connections.
Examples of single-ended but balanced connections are are RCA SPDIF (digital) and antenna connections.
analog interlinks
Interlinks are connections between devices, say a microphone/instrument and pre-amplifier/mixing console, ADC, DAC and/or (pre)amplifier. Also between pre-amplifier (or mixing console) and power amplifier or between source and/or active (monitor) speakers.
These connections can be ‘balanced’ (actually differential) or single ended.
Differential connections have a distinct benefit. This isn’t ‘sound quality’ but is about ‘ground’ connections between equipment. With single ended connections both the audio signal + unwanted leakage currents travel through the ground wire. Because of this those unwanted signals will enter the audio path.
With differential connections the audio signal has its own path and the unwanted leakage currents travel through a different path (common reference wire and or shield) and can not make it into the audio path.
So… differential connections will prevent the dreaded ‘ground loops’ and can insure a clean signal transmission. One could call that a ‘sound quality’ aspect though.
In a single ended connections the signal is present between a signal wire and a reference wire (usually the screen). RCA, DIN, BNC, TRS (for stereo) connectors are examples.
In ‘balanced‘ (actually differential) connections there are 2 signal wires which both carry the opposite polarity signals. So the actual signal between the 2 signal wires is double that of each signal opposite the reference (which are the blue lines in the picture below that are connected in reality).
The usual connectors are TRS plug/jack (also used for stereo single ended) and 3-pin XLR connectors.
As a third connection there can be a ‘reference wire’. This reference is required for electronics that is DC coupled and needed in case one only wants to use 1 of the 2 signal wires.
Then there can also be a separate shield connection (which conducts unwanted leakage currents).
The separate reference and ground (shield) can only be achieved with XLR connectors.
benefits of ‘balanced’ (differential) connections
A balanced (differential) interlink connection can eliminate common mode noise issues.
This is when you hear weird sounds that should not be there (hum or other sounds) and disappear the moment you remove the analog input cables.
When this is not the case (hearing unwanted noises) while using RCA then there is no practical benefit in going balanced.
‘Balanced’ interlinks are designed to provide a more (potentially) problem free connection with high quality connectors (XLR).
‘Balanced’ speaker and headphone outputs have the benefit of reaching higher output levels compared to when the same device is used single ended. Particularly helpful with portable gear because of their low internal voltage rails and speaker amps fed with relatively low power supply voltages that are considered safe.
Balanced out (differential out actually) of an amp can be useful if the SE out (TRS) does not play loud enough and you need a few dB more max. output level.
This could be interesting for portable gear combined with insensitive higher impedance headphones. There you can get double the output voltage (4x more output power) which means almost twice as loud.
That would be the only reason to go differential out.
A lot of myths are going around in the audiophile world about balanced having a better sound quality.
One would need to define sound quality here.
When one means ‘sound quality’ of the source + added (unwanted) signals such as noise, hum, weird sounds means reduced sound quality then yes… the ‘sound quality’ of a compromised signal is not as good as when there are no added (unwanted) signals present. At least those that reach audible thresholds.
When there are no ‘added unwanted’ signals when using RCA (single ended) connections then there is absolutely no difference between single ended and balanced connections. The sound quality is the same.
Balanced headphone outputs are particularly handy when driving insensitive headphones.
Those are the headphones with sensitivity numbers below 105dB/V.
‘Balanced’ headphone connections (or should I say independent L and R out) can be audibly different to TRS jack outputs when 2 conditions are met.
Those conditions are:
- a 3-wire headphone cable is used.
- the common return wire has a relative high resistance opposite the headphone impedance.
In other words there can be a difference in stereo imaging between TRS out and 4-pin (or 5-pin in case of Pentaconn) outputs.
This is caused by crosstalk but not one that makes the sound a bit more ‘mono’ but one that makes the sound artificially ‘wider’.
Normal crosstalk adds the left and right sounds as the signals have the same polarity, but the crosstalk we are talking about here subtracts left and right signals as the polarity is opposite.
Even a common mode wire resistance above 0.2Ω can have an audible impact when low impedance headphones are used but a 1Ω wire resistance is not an audible concern when high impedance headphones are used.
A return wire is the wire running from sleeve of the 3-pin connector in the headphone to the sleeve of 3.5/6.3 TRS plug. This wire is used for both drivers.
Cross-talk is not the same as cross-feed, in fact the effect is opposite and has a ‘widening’ effect whereas cross-feed has a ‘narrowing’ effect.
When a signal is applied to one channel a current will flow. That current will create a voltage drop across the return wire. That voltage is inverted in polarity opposite the applied voltage so subtracted from the applied signal. By itself not problematic other than some (impedance dependent) attenuation but… when there also is a signal applied to the other channel that dropped voltage will double for ‘mono’ signals and is subtracted (polarity inverted signal) from the other channel lowering the level of the mono signals.
In case there is stereo info (L and R having different signals) that stereo signal will be reproduced inverted in polarity in the other channel. This means the stereo image is ‘widened’ artificially and is not desirable when it becomes too artificially ‘wide’.
The mechanism behind this is shown below in the form of a schematic.
The lower the impedance of the headphone is (below 50Ω it might become an audible issue) and the higher the resistance of the return wire is the worse the effect is. Longer cables are likely to have a resistance between 1Ω and 3Ω or so.
In some cases I even measured the signals intended for the left channel at -25dB in the right channel. This is potentially audible. Any crosstalk below -45dB is inaudible.
This affects stereo separation and imaging. In fact, stereo imaging becomes a bit wider and mono signals are attenuated a little (< 1dB in any case).
4-pin headphone out thus is always (theoretically) ‘better’ in this aspect.
This has nothing to do with the signal being differential (balanced) or single-ended any other headphone amp with XLR/Pentaconn outputs that have the same output power from TRS and ‘balanced’ out.
It is because the headphone cable is 4-wire and has separated signal paths to each driver where as the TRS has a shared ‘return wire’.
Is a TRS always a problem ?
No.. there are plenty of headphone cables with TRS connection that do not have this issue and are just as ‘good’ in this aspect as 4-wire connections.
This can be for 2 reasons:
- The cable is 4-wire all the way up to the 3.5/6.3 TRS jack and joins the return wires in the plug.
In general most dual entry headphones (with a connector in each cup) are all 4-wire internally. - The 3-wire cable has a low resistance and the headphone is higher impedance.
Headphones that have a connector on one side only and have a 3-pin connector in the headphone itself are guaranteed to be 3-wire. When these headphones are low impedance and have long cables then this can be audible.
But … there are also ‘single entry’ headphones that have a 4-pin connector in the headphone itself and these are basically also 4-wire (in general, there is no guarantee) and thus are not ‘problematic’. One should not use extension cables here though.
This does not mean that any device with 4.4mm Pentaconn or XLR-4 connector on it actually has a differential output. In some cases those connectors are only ‘for convenience’ so that one can connect all kinds of cables without having to resort to using converter cables or has to buy another cable.
The actual output signal in such cases is single ended but internally the inverted signal output pins are tied together to the common/ground/reference.
Those outputs are not differential but you do make use of a guaranteed 4-wire cable.
The above is all the technical story and that may not align with ‘perceived’ differences in sound quality.
That, however, is an entirely different story and not of signal/electrical origin but is a perception thing (brain thing actually).
This means that while your question is answered technically it isn’t answered ‘sonically’.
Information about most common audio connectors for analog mono/stereo signals for balanced as well as single-ended is found HERE
differential speaker/headphone outputs
Every speaker and headphone driver in principle does not care whether it is driven single ended or differential. This is because it has only 2 connections and does not have a ‘ground reference’.
Reasons for using differential outputs are determined by the circuit design.
An amplifier with an output transformer are almost always differential by nature.
Another reason for using differential outputs has to do with the maximum available power supply voltage.
For instance battery fed devices or (speaker) amplifiers with a limited output or power supply voltage or circuits that are fully differential by design.
A differential circuit can reach double the output voltage (so 4x the output power) of a similar circuit operating on the same voltage.
This is because a differential output stage has 2 similar amplifiers internally that have opposite polarity signals. At the output, between the 2 opposing signals, the voltage thus is double that of each signal opposite the internal reference (ground).
Each channel thus requires 2 signal wires and no ground (common/reference) is present.
For headphone amplifiers this thus requires 4 connection pins.
A TRS jack only has 3 so cannot be used.
For differential outputs there are 4 commonly used connectors.
4-pin XLR, 4-pin mini XLR, 2.5mm TRRS mini jack and the TRRRS 4.4mm Pentaconn connector.
This Pentaconn connector has 5 pins and the 5th connection (the sleeve) is the common/ground/reference. This sleeve is required for single ended usage and screened differential connections (interlinks).
All amplifiers have a voltage limit and a current limit. voltage x current = power.
When one wants to double the voltage one can put those amplifiers in series.
This doubles the voltage but NOT the current.
When one wants to double the current one must put the amplifiers in parallel.
This, however, doesn’t double the voltage only the current.
When an amplifier is bridged (used balanced) there basically are 2 amplifiers in series.
This means double the voltage but not double the output current (when the amplifier sections are current limited).
When one takes a look at output voltages of balanced and RCA output DAC’s as an example. The RCA out is 2V then the XLR is 4V. As there is as good as no load at line level these voltages always double.
Now comes the output power part, there is a lot of confusion about this.
Lets assume the amplifier in question has unlimited current (for argument sake) and can put out max 10V in SE and 20V in balanced.
some calculations for different impedance loads (assuming there is NO current limit).
‘single ended‘ = 10V and ‘balanced‘ = 20V
8 Ohm = 12.5W (1.25A) and 50W (2.5A)
16 Ohm = 6.25W (0.625A) and 25W (1.25A)
32 Ohm = 3.125W (0.313A) and 12.5W (0.625A)
64 Ohm = 1.56W (0.156A) and 6.25W (0.313A)
128 Ohm = 0.78W (0.078A) and 3.125W (0.156A)
256 Ohm = 0.39W (0.039A) and 1.56W (0.078A)
512 Ohm = 0.19W (0.019A) and 0.78W (0.039A)
It is evident that when the output voltage is doubled the output current is also doubled and as a result the power is 4x higher.
What is also clear is that a lower impedance requires more current than a higher impedance load.
Now comes the more difficult part in this story. All amplifiers are current limited.
This means that for instance when a headphone amplifier can deliver 10V max (single ended) but is limited to 250mA (0.25A).
In balanced mode these are in series so the output voltage can be double (and power quadrupled) as long as the current limit is not reached.
The amplifiers are in series seen from the load so max. current remains the same in SE and balanced mode. Power = (current x current) x resistance.
So for single ended (max 10V) and balanced (max 20V) we can see at certain impedance and 250mA current limit, voltages above 10V and 20V respectively are required but are not available because of the voltage and current limits in practice.
8 Ohm = 0.5W (2V) and 0.5W (2V) (current limited, no increase in power)
16 Ohm = 1W (4V) and 1W (4V) (current limited, no increase in power)
32 Ohm = 2W (8V) and 2W (8V) (current limited, no increase in power)
64 Ohm = 1.56W (10V) and 4W (16V) (voltage limited & current limited)
128 Ohm = 780mW (10V) and 3.125W (20V) (voltage limited only, 4x the power)
256 Ohm = 390mW (10V) and 1.56W (20V) (voltage limited only 4x the power)
512 Ohm = 195mW (10V) and 780mW (20V) (voltage limited only 4x the power)
For low impedance headphones the power is limited by current. This is the same for both amps so below a certain impedance the max. power is the same as shown in the current table BUT the voltages associated with that voltage can not be reached.
For high impedance the max power is determined by the output voltage so above a certain impedance the output voltage can be up to 2x higher in the balanced (20V) version.
As can be seen above a certain impedance the power quadruples and below a certain impedance the power is actually the same with a small transition between same power and quadruple power between 32 Ohm and 128 Ohm and peaking somewhere around 64 Ohm in this case.
At 10V and 250mA one can calculate the maximum power as being 2.5W for which one needs 40 Ohm.
At 20V and 250mA the max power is 5W for which one needs 80 Ohm.
For speaker amplifiers there is also a voltage and current limit. This is the reason why amplifiers are rated for 4-16 ohm loads but when used bridged (differential) the current would become too high so in bridged mode the load is only specified >8 ohm.
Can headphones be connected directly to speaker output terminals ?
What about headphone power and speaker power how are they related ?
Do you need a resistor divider network and how to calculate and make them ?
The answers for this are found ON THIS PAGE
DIY-Audio-Heaven 