What is balanced? What are balanced amps? Do they sound better? Discussion for noobs and boobs.

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by purr1n, Dec 5, 2015.

  1. neo_the_one

    neo_the_one Acquaintance

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    One thing i could not fully understand in this case. For transformer-coupled tube amps, should the SE output and balanced output then sound the same?
    My STJ's SE output and balanced output sound a little different.
     
  2. purr1n

    purr1n Burned out

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    The STJ SE phono jack grounds one leg of the secondaries. Differences could be this or the result of better connection with the 4-pin XLR. Some people think headphones like the HD800 have better staging from the balanced outputs.
     
  3. BarryT

    BarryT MOT: Austin Audio Works

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    Hello, I would like to offer you all a thought that has not been addresses so far.

    1 - The real operational difference between Single End and Balanced is that the Left - and Right- signal paths are commingled in SE into a single conductor. In fact they are commingled (entangled?) with all the currents flowing in the 'ground' paths in the system,

    Mach is right, everything affects everything else in the universe. It's all about how much.

    2 - Information transfer in through a conductor employing electrons is carried as a TEM (Transversal Electro-Magnetic) Wave between the two conducting conductors. It is a field. The dielectric (stuff between the conductors, insulation and air) sets the speed of the wave in the cables.

    No, signals to not travel at the speed of light, even in air. The term is Velocity of Propagation. You 'dial in' the VP by choosing what's between the conductors carrying the balanced signals.

    As an aside, when a balanced signal system is forced to be unbalanced the energy lost in the imbalance state emanates from the conductor into space-time, they become radio waves. Radio guys make an unbalanced state by sticking one side of the balanced signal up in the air, the other side they stick in the Earth, which is where our word 'Ground' comes from. Here is more about that - https://sidstation.loudet.org/data-en.xhtml VLF Radio 15-19 kHz

    3 - Even though the physics argues that the signals all straighten themselves out when put to respective load (I have lab-tested this argument, it essentially is true) I have found that a very abstract sonic image issue rests here.

    Something we collectively call 'soundscape' and is by no means objective, tends to be a better illusion when you don't commingle grounds.

    I have had the privilege of being able to design and build to production many audio products and had a LOT of reviews,comments, critiques, etc on each. To me each product has been an experiment, each review a fantastic learning experience, all helping me to learn a craft to become an art. This 'Soundscape' thing, when present in recordings is astounding, I have slowly gained that certain physical attributes of a 'build' of hardware in effect the effect,

    Just a thought after years of conjecturing, I would to further explore with you.
     
  4. recstar24

    recstar24 Friend

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    Sorry for the long-standing bump, but I thought the following article was pertinent:

    https://benchmarkmedia.com/blogs/application_notes/audio-myth-balanced-headphone-outputs-are-better

    Recently discovered that the xlr headphone output on my HPA4 isn’t necessarily a “true” voltage balanced source, but simply a xlr output with separate ground returns for the left and right channel. Regardless, Benchmark makes a compelling argument that balanced headphone drive may not necessarily provide additional performance benefits.
     
  5. BarryT

    BarryT MOT: Austin Audio Works

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    Albeit 6 weeks delayed (finished the kitchen remodel and hosted the wedding of my son, a delightful event) I read the Brenchmark text finding it offering many interesting points.

    I have written before about the idea of 'entanglement" , the idea that the left and right signaling, when combined in a single conductor such as a ground line, contaminate each other in subtle but perceivable ways.

    While stretching the quantum concept of entanglement but the audio signal you like so much is in fact a quantum level event. Current Quantum Theory suggest that magnetic fields are photonic in nature and thus elemental quantum particles), I would point out that the practical fact is that higher quality performance in hi-fi hardware favores "Mono-Block" solutions.

    Mono-blocking is the epitome of channel isolation which is effectively manifested in the employment of truly balanced amplification. That is a separate amplifier for each conduction of a stereo audio signal, thus in stereo signaling four individual amplifiers must be employed with no signaling in the 'ground'.

    Benchmark points out the importance of full balanced operation by noting that all its interfaces to the outside world are balanced. They are quite right in this approach and are to be congratulated for expanding it, it is the way we have done on the recording side for decades, why not continue the conjecture to home reproduction too?

    So why does this logic stop when it comes to headphones?

    The answer is that it doesn't. Balanced interfacing must be continued in its purest form all the way to the transducers on the sides of your head.

    Thus I submit to you The Black AMP - four identical high-performance current amplifiers without that destroyer of good audio, electronic feedback.

    Please remember the AAW motto - "Feedback sucks the life out of your music"

    Thank you for the forum to offer these thoughts.

    Barry

    Barry
     
  6. purr1n

    purr1n Burned out

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    Sounds like more opportunistic marketing bullshit from Benchmark, this time as a lame excuse for the fact that they provided a 4-pin XLR output, but that this output doesn't provide a differential (balanced) signal. Separate grounds doesn't count. Just calling it out because no professional audio reviewer will.
     
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  7. roderickvd

    roderickvd Rando

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    Why doesn’t that count? Not doubling the impedance, crosstalk still being minimized through separate ground returns, seem like real things to me.

    Full disclosure: I own and like my fully balanced Singxer SA-1.
     
  8. purr1n

    purr1n Burned out

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    It doesn't count as balanced because it's not balanced.

    Separate grounds isn't balanced. The signals are not differential. There's no common mode noise rejection, reduction of even harmonic distortion, etc. It isn't even really separate grounds because eventually the grounds connect somewhere. This is the essence of single-ended connections.
     
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    Last edited: Jul 4, 2022
  9. roderickvd

    roderickvd Rando

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    Of course. I misunderstood thinking you meant that SE can be no good. But if Benchmark says it’s balanced when it’s not, then yeah marketing BS — shun!
     
  10. purr1n

    purr1n Burned out

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    I believe that balanced is kinda dumb. This from a pragmatic view because balanced cables, yet another expensive add-on, and more effective use of resources to better a SE design than double the parts (usually) to get differential drive.

    If Benchmark made a balanced amp, they would write a marketing paper why balanced is better overall to SE. They are kind of annoying this way.

    I blame Tyll / Headroom this this balanced gear craze.
     
  11. songmic

    songmic Gear cycler East Asia edition

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    The only reason I opt for balanced is because it eliminates ground loop.

    I've lived in over 4 different houses/apartments during my audio journey, and all of these homes (even recently built ones) had some sort of ground loop issue with my unbalanced audio system. I even checked the outlets with a voltmeter to see if they were properly grounded, and even if they were, ground loop was always a problem for some reason.

    For reasons unknown, my OTL unbalanced amps (e.g. ZDS, Teton) never had a ground loop issue. On the other hand, SET amps (e.g. Studio B) and SS unbalanced amps (e.g. Asgard) almost always produced a ground loop hum when connected to a single-ended source. Using the balanced outputs of these amps (Studio B only has SE inputs but a balanced as well as SE output) did not matter, the only thing mattered was that the DAC and amp were connected with balanced XLR cables. My EC Studio didn't have ground loop because despite it being an SET amp, it had balanced input transformers.

    For years I tried to solve this problem, but to no avail. In the end I was like fuck it, I'm only using amps with balanced inputs, with OTL amps being an exception.

    If anyone might have an idea why this is happening to me, please feel free to chime it. Otherwise I'm stuck with balanced like it or not.
     
    Last edited: Jul 4, 2022
  12. BarryT

    BarryT MOT: Austin Audio Works

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    I would like to offer a thought in this thread. It is about balanced signaling in quality stereo audio systems.
    Setting aside all the arguments presented thus far, let us look at the most fundamental aspect of what is going on here.

    1 - Audio signaling using electricity requires two conduction paths; it is an Alternating Current signal. This suggests that two independent signals (such as stereo audio) will require 4 independent paths or conductors to go from source to load.

    2 In 'single-end' or unbalanced signaling one of each of the two signals is combined into a Common Signal that we euphemistically call "Ground". In effect 4 wires become 3 wires, two signals and a ground. This Ground Signal is really (-Left)+(-Right). These signals are commingled into one new signal. In the case of a chassis ground all signals plus the power supply power supply are commingled.

    I humorously borrowed a word from Quantum Mechanics that fits this in a way, I call it "signal entanglement". (-Left) and (-Right) are ineffably encoded together as a new Transverse Electro Magnetic (TEM) Wave , guided physically through space-time along the conductor and through the dielectric. This is the physical form of the audio data.

    The individual signals split back out of the common conductor based on the presence of the other half of the signal which is out of phase. Can we say opposites attract here? Yea, kind of - but that is another discussion. For now all we care about is that they split apart
    I am confident of this because I have tested the phenomena in my lab and you do it all the time when listening.

    One more thought before I get to the conclusion.

    We as a community tend to agree that cabling affects the subjective performance of an audio system. For this to be true the TEM wave has to subtly change in flight. It is distorted by its flight from source to load through the connecting cable. This new signal is not distorted the same way as the other two signals, i.e. individual +Left+ and +Right. The geometry of space-time is different for the ground and the signal.
    This signal "difference" is defined as CUB, Capacitance UnBalance and it is a distortion like ground pumping in single ended systems. Our "ground" stays the same potential (we fixed that problem with balanced), but the offset amplitudes on BOTH sides of the virtual ground are changed by CUB tolerances. The advantage is we ISOLATE the SIGNALS from the rest of the system's variations.

    If the differential signal is magically perfectly separated by the opposite signal at the end, what happens to the difference in the signals? Mother Nature doesn't like this kind of crap, that energy has to go somewhere.

    Energy that can't be used is REFLECTED until it is attenuated or atrophied out. T he line impedance change due to CUB causes irregular TEM properties. The transfer function loses information. CUB is that confusion as it varies down the cable. CUB is the BULK to ground difference in percent but the underlying issue is IRREGULAR TEM properties of the transmission line. It can't be perfect.

    This is a form of Entropy. If so then we are experiencing Information Entropy. Confusion (distortion) that alters the information.

    Ouch, sounds like the way you can describe a cable sounding.

    So what is Balanced about? Try Sonic Information Entropy Reduction where less is better.
    --
    Barry Thornton
     
  13. recstar24

    recstar24 Friend

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    I’ll need to reread their article and marketing but I believe they don’t officially call it balanced out or they definitely don’t use the term differential in regards to the headphone out. If anything they appear to say they don’t agree that balanced/differential drive offers any benefits from a headphone out perspective
     
  14. BarryT

    BarryT MOT: Austin Audio Works

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    I thought I might note that from a manufactures viewpoint a balanced output or bridging amplifier has 4 times the output of either of the two amplifier sections involved. While current goes up more important the power supply voltage doesn't. It's a numbers game, a few more transistors in the output stages don't cost much and are far more reliable, don't need higher voltages. A pair of 50 watt amplifiers bridged is 200 watts. cheaper and safer than one amplifier of 200 watts. Gets more impressive when you consider that a pair of 250-watts amps give you full gallon (1,000 watts).
     

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