Headphones & Amps: Balanced vs Unbalanced

headphone-amp

#1

Been doing a lot of reading about balanced vs unbalanced headphones and amps. Came across a paper published by Benchmark Systems about the myth of balanced headphone amps. The summary was:

The result of balanced headphones is less damping factor, more distortion, and more noise. Also, balanced headphones configurations offer no real benefits, to boot.

They said the only advantage was more power with the ability to play louder. So possibly the difference in or preference for balanced configurations is due to the ability to play louder and distortion that adds euphonic warmth.

They said balanced connections are important for other types of audio connections just not headphones. Interesting reading. You can visit their sight for the full article.


#2

Beyond increased power, for a fully balanced, differential, amp/headphone configuration, the biggest benefit is the fact that each driver has dedicated grounds. This reduces crosstalk to a measurable, and often audible, degree.

Even doing blind testing, this tends to result in reliably discernible improvements in stage, resolution and micro-dynamics.

It is, for sure, a “last few percent”type improvement … and the quality of the amp and transducers are a much bigger factor than balanced vs. single-ended headphone drive. But it’s still an improvement.

Seperate grounds, though, is worthwhile … which is often described as “balanced” when it comes to headphone connections (a dead giveaway is if power isn’t at least doubled for the “balanced connection”…

As an example, my big Woo headphone amp is actually a pair of mono-blocks. Each is a single-ended amplifier. So each driver/cup has a fully discrete amplifier feeding it. But they also have dedicated + and GND lines as a result. And that’s the real benefit to the arrangement.


#3

I think Benchmark’s point is that even though some may prefer the sound of the Balanced output, on the bench the SE output measures cleaner with less distortion and from a purely objective view is superior. Kind of similar to those who prefer tubes with their inherent measurable deficiencies.


#4

If you’re talking about this article, then you’re taking situationally correct statements and applying them as absolutes … which is not what the article actually says.

Its statements are qualified with “may”, “in many cases”, “usually” and so on. And that’s with good reason … because they’re not universally true. It’s very much a simplification of the actual state of affairs and. Showing suitable measurement would be good as it’d put what they’re saying in proper context.

Yes, noise will typically increase if you just take a single-ended amplifier, pair it up with a second one, run the second amplifier inverted, and use that to drive your output (that’s all a balanced amplifier is). It’s almost always the case that that noise remains below the threshold of audibility.

Will distortion increase? Maybe. However, depending on the parameters of the design and it’s implementation, other distortion products (i.e. not simple noise) may well decrease as the amplifiers can be more easily made to operate within a sweet spot for bias and linearity as they only have to work half as hard for the same effective output level.

Damping factor halves … okay … technically … but is 0.2 ohms vs. 0.1 ohms really relevant into a 50 or 300 ohm load? Nope, not. really. It might be, at a stretch, into a super-sensitive, low-impedance IEM, but even the 8-9 ohm designs are still seeing a damping factor of several times the recommended 8-10x.

In many cases you can test if a specific amplifier is performing worse into your specific load, at your specific drive level, in single-ended vs. balanced configuration directly - by only driving one side of each channel and only taking output from that same side and measuring that.

But it’s not really surprising that a company that doesn’t produce balanced headphone outputs is going to put up an article that say’s they’re not always better.. (As it does NOT say they’re always worse).

Without specific examples and measurements, which would only be “objectively superior” for that case and not universally applicable, it’s just a position piece, not an engineering or scientific paper.


All that said …

You absolutely should worry more about pretty much every other aspect of an amplifier design, topology and implementation before you start worrying about whether it’s balanced or not. And there are plenty of single ended amplifiers that sound better than balanced ones.

There are, of course, definite disadvantages to a balanced amplifier … the biggest typically being value.

It will cost, generally, about twice as much on the BoM as a single ended version of the same amplifier. Though often it’s more because it as well as doubling up on PSU capacity and the number of amplifiers circuits it must provide, it’ll include additional circuitry to let single-ended sources drive the balanced amplifiers (which requires phase inverters or transformers), and to allow a balanced source to feed a single-ended output (which requires summers or transformers).

This tends to mean that if you spend $1,000 on a single-ended amplifier, it’ll be “better” than a balanced amplifier at the same price. And that’s often simply due to the balanced design not being able to use a design, or parts, that cost as much as the single-ended alternative as it needs twice as many of them.


Many tube amplifiers are designed in a way that does, indeed, increase harmonic distortion and, typically, they’ll exhibit higher noise than well-done solid-state designs. However, “many” and “typically” is not “all” and it is entirely possible to design and build a tube amplifier that measures as well as a solid-state device. It might cost more to do it depending on what bandwidth you need, but there’s nothing inherent to tubes vs. transistors that makes solid-state amps universally superior.


Proper application of the appropriate technology in a suitable design makes most of these “absolute” or “definitive” statements into what they really are … more “myths” and “beliefs”.

As with most things in life, the truth is almost always somewhere in the middle.


#5

Thanks Torq for you comprehensive reply. Yes that was the article. I understand what you’re saying. You have to admit this is an interesting subject.


#6

Torq I want to drink whiskey and listen to music with you and pretend I know what you’re talking about :slight_smile: seriously though you are a wealth of great information, thank you for sharing it with us audiophile peasants, I look forward to learning a lot from the people in this forum!


#7

lol DarthPool, I agree. I once mentioned the possibility of Torq being way too involved for his own safety and the possibility of him damaging his personal relationships due to the intensity of his pursuit in this field. But it’s making sense now. Who better to understand and communicate an unbalanced principle, than someone who might share that same definition?? As in dealing with an unbalanced atom that is in an ionic state, the higher energy level is unnatural but highly useful if directed appropriately. This kind’a sums up Torq (who hopefully knows I"m teasing him). But, I’m definitely glad he’s here and willing to share his knowledge.


#8

I certainly cannot add to the explanation given as it is exceptionally comprehensive. My personal experience, as limited as it likely is compared to many others on the forum, is that the additional power and lack of noise on the balanced set up I use was something I could not find in a single ended system at the time of purchase.

I picked up a Little Dot MK-VII+ amp when they were still stocked by LD and paired it with a silver balanced cable for the Senn 650s. As much of a skeptic and bargain hunter as I was, I couldn’t deny that the balanced connection provided a punch and clarity at higher volumes which had been missing with other SS amps I had tried near the same price point.

A year or two after I bought the VII+ I was going to recommend it to someone but when I spoke to LD (David Zhezhe?) I was told that the cost to manufacture them had become too much to build them on spec. He said they could special order it (at the time) but that the cost would be significantly more than what I had paid.
I’m sure there are likely single ended amps now that sound as good or better for the price but I’m afraid I became somewhat biased towards a balanced set up. Perhaps it’s largely due to the lack of interference and/or ground loop problems from the source to the amp as well.
As far as I can remember this application is mentioned as an advantage, even in the article you referenced but it’s a long time since I read the Benchmark write up (I may read it again if only to check my facts :wink: )

Even after this long I don’t feel much need to upgrade the amp but my DAC could certainly be improved on.
A tube amp has been a big a temptation (as are top tier cans) but I’m afraid I might end up in the poor house if I start up searching for audio nirvana again! I’m still happy with what I hear from this old gear but always keep my eyes and ears open.


#9

sometimes it also helps to start with the basics…the purity of the music you are listening to. If your source is bad, then nothing will help. We’ve all heard music with the “pops and clicks”, the sharp noises that hurt the ears and force us to listen at a lower level. But with good clear music, you can also hear the improvements in your gear. Headphone listening seems to magnify this impact, making you appreciate it even more when you have the gear that truly lets you hear the music and everything in it. So make sure you have good clear music as part of your set up.


#10

Yes I agree. This is a lesson I have learnt only in the past couple of years. Always striving for better sound quality it can be easy to forget your source and just chase after increasingly expensive gear in order to reach better SQ.

Source is ‘so’ important, like many have said just buying better headphones and amp’s will amplify the poor source and not improve the music itself. Listening to clean, well produced music on a good source always enhances my listening pleasure.
-Paul-


#11

I used to be balanced freak, then I read more about it and concluded it does no good to the SQ, and the low-efficiency headphones I used back then to justify the increased voltage output are now sold.
It does add to the complexity of the system, and in fact even increases IMD and noise.


#12

IMO a balanced connection from DAC–>Amp certainly doesn’t hurt in the hum/noise rejection department.

I may have to revisit things with more recent gear as it certainly is cheaper for someone to remain with SE.
It would even be cheaper to revert to SE for any new gear, so I guess I’ll do some listening for myself again soon enough.

I do listen at higher volumes at time, so it will be an interesting comparison again, albeit with more and newer designs.


#13

I was a purely balanced guy for many years! But I later found out that the design and overall quality meant just as much as the topology.

An as @Torq mentions, dedicated grounds for each driver are a step above Single Ended assuming all else is equal.

But for the best value and performance respective of the price your willing to pay, it’s really best to either hear something for your self or look at product reviews from a variety of trusted sources. As the topology, implementation and even manufacturing quality all play an impact on the overall fidelity of what ever your plugging into

And to restate what’s already been said

Proper application of the appropriate technology in a suitable design makes most of these “absolute” or “definitive” statements into what they really are … more “myths” and “beliefs”.

As with most things in life, the truth is almost always somewhere in the middle.


#14

Concretely, has anyone tested the recent modest-priced dual/balanced Amp/DACs?

I’m curious about any perceptible auditory differences between the four below, as well as versus non-balanced products in the same price range.

Balanced Topping DX7S ($500) vs.
Dual-DAC Topping DX50 ($250) vs.
Balanced SMSL IQ ($139) vs.
Balanced Sabaj Da3 ($120)

All products and prices as listed at Amazon.


#15

Sadly I’ve not but what may be of interest to some of you is a portable feature I’m prepping at the moment! Featuring a variety of both balanced and single ended portable amps and Dac/Amp Combo Units. With a variety of headphones or “loads”


#16

I look forward to your feature. I am just dipping my toe in the balanced side of things with my newish Dap. So far I think I hear a difference but it may simply be placebo. But I didn’t buy the dap for the balanced feature so it’s a bonus. All it’s cost me is a few quid for a cheap balanced cable. Better sound via placebo? Either way I don’t mind.
-Paul-


#17

For me, having gotten into the hobby recently, I did a ton of research on this as well, have tried a ton a gear, and here’s been the key for me: build an optimized chain with “synergy” and don’t worry about balanced … and building that chain up to end-game stuff will take a long time for a few key reasons: training my ears and money.

Of course anyone (with the cash) can go spend $30k on an end-game setup, but if you haven’t tried a lot of other set-ups you have no idea if it’s the ideal one for you. let’s say I decide to buy a mono-block Woo setup like @Torq , well maybe it turns out I don’t like the Woo sound as much as solid state … and etc etc.

so the point is, if I’m doing a lot experimenting with mid-fi moving to hi-fi setups, and always trying to do that balanced, it will cost me way more (and for me take me way more time) than if I just find some great headphones I like, find an amp that works great with them, find the right DAC, etc.

As an example, for my ZMF Atticus I’ve been looking at (and experimenting with) all kinds of OTL amps, and some not. Some of them are balanced, some aren’t. For my Eikons, they sound pretty dang good out of my Jotunheim which is … kind of balanced :slight_smile: For the Atty, I’m considering a Decware CSP3-25, a Woo WA2, a Woo WA5-LE, or a Glenn OTL … I may just start with a Schitt Valhalla though as I can’t decide :wink:

Anyway, the point is, I’m not worrying about balanced, just synergy with the Atticus


#18

Hi sorry my initial post was totally off kilter so I will start again.


#19

Right I shall try again. I totally got the direction of the discussion wrong.

Balanced, yes, I own a pioneer Dap which is capable of running my iem’s in balanced mode via a 2.5mm TRRS. Having started using this I now prefer to use my iem’s in balanced mode.

Having tasted the perceived advantage of this method I naturally start to think I should really see if it makes much difference on my full size headphones. So when I get another Amp I will get one with a balanced as well as single ended output. Whether or not this makes a hoot of difference sonically remains to be decided. Although the extra power output will come in handy. I would really like to try out the Bottlehead Crack with its supposed synergy with the higher impedance Sennheiser’s. And maybe roll a few tubes. But for the balanced part I will get a SS amp as I feel the need for an upgrade.

You certainly have some nice gear and if you do end up getting something from Woo then I am sure it will only enhance your audio experience. :grinning:


#20

Balanced makes a predictable and substantial difference to my ears. My Elex came with a standard cable and a 4-pin XLR cable. As I was generally moving toward compactness and mobile, I then bought a standard/balanced FiiO Q5 amp/DAC (basically a portable DAP without storage, as it must be linked to a phone or PC). So, my Elex XLR cable found a home. Long story short, balanced gave the headphones:

  • More power
  • Less noise, blacker background
  • Better left/right channel separation
  • Less mid-high range glare (notes become narrower and more precise)
  • More definition for all tones top to bottom
  • More precise dynamics

Because I really liked the Elex on balanced, I bought a balanced cable for my new Aeon Flow Closed. Long story short, I dislike balanced for almost exactly the same reasons listed above. The high end is sharper and more peaky. The bass remains defined but seems weaker and less warm. Overall, balanced makes the closed headphones unpleasant, as they inherently transmit all minute changes in air pressure. My preliminary conclusion is that the AFC drivers were voiced (very carefully) to create a pleasant experience on single-ended amps. Voicing is tricky with closed headphones.

Now that I’m on a roll, I ordered a balanced cable for my old HD-600s and will do a more systematic comparison after it arrives.