[Rob80b]

  I share your skepticism.
 
Balanced was designed for pro situations, like mics with very low level signals and high output impedance traveling along a 50' cord. That's a worst case scenario begging for hum/noise which balanced eliminates or at least reduces........
 

Balanced headphone connections and balanced interconnect connections should not be confused as they do not serve the same purpose, balanced interconnects as you've noted are used mainly to reduce noise though cancellation by incorporating a +  a - and a common ground. Headphones being a passive devise are more or less immune to noise due to grounding or RF signals and even very long runs of single ended headphone cables will not be inherent to induced noise, resistance and a change in impedance possibly and balanced headphones are powered with a left + and - and a right + and - signal and do not share a common ground and therefore totally discrete, no cross-talk.
 
Quote:

If I'm not mistaken, push/pull implies balanced by default. So what you're saying is the balanced output makes the balanced output shine.

Possibly….the Bryston BHA-1 in discussion does supply a discrete + & - signal in balanced mode to the headphone which could be beneficial to some headphone drivers.
I’ve only had my LCD2.2s for a short while but being planar magnetics they do appear to benefit the most from the balanced connection more than all my other previous dynamic headphones with added stage width and depth and possibly better base over the single ended connection.

 

[BassDigger]

If I'm not mistaken, push/pull implies balanced by default. So what you're saying is the balanced output makes the balanced output shine.

  Balanced headphone connections and balanced interconnect connections should not be confused ...
 
  ….the Bryston BHA-1 in discussion does supply a discrete + & - signal in balanced mode to the headphone which could be beneficial to some headphone drivers.
I’ve only had my LCD2.2s for a short while but being planar magnetics they do appear to benefit the most from the balanced connection more than all my other previous dynamic headphones with added stage width and depth and possibly better base over the single ended connection.

 

 Are we still down this rabbit hole?
 
Ok. I can see why a push/pull design could work better, with planars, with their higher power requirements and the way that they have a trace through the driver, rather than a coil.
 
It reminds me that single-ended outputs, are just that; outputs from a single-ended design. But, does that mean that all balanced headphone outputs are push/pull?
 
That's why this rabbit hole is such a distraction; there's even confusion about what 'balanced' means!

 

[Rob80b]

SE =/= balanced on the BHA-1. The SE is a summed output from the balanced section, which usually alters the signal. If I'm mistaken, please use facts, not anecdotes and mythology. Balanced and SE are merely different, not in a hierarchy.

Maybe I have misread you…but you cannot sum neither the minus nor positive outputs from a balanced amp such as the BHA-1 as that would combine the left and right channels…. definitely a no no. The single ended out put comprises solely from the left + and right + and chassis ground…although one would get the same results using the left – and right – and chassis ground.

 

[CanadianMaestro]

   

 Are we still down this rabbit hole?
 
Ok. I can see why a push/pull design could work better, with planars, with their higher power requirements and the way that they have a trace through the driver, rather than a coil.
 
It reminds me that single-ended outputs, are just that; outputs from a single-ended design. But, does that mean that all balanced headphone outputs are push/pull?
 
That's why this rabbit hole is such a distraction; there's even confusion about what 'balanced' means!

See this post from James Tanner:
 
http://www.head-fi.org/t/560499/new-headphone-amplifier-from-bryston/1590#post_11716014

 

[MRC001]

If I'm not mistaken, push/pull implies balanced by default. So what you're saying is the balanced output makes the balanced output shine.

Audio terminology can be ambiguous and confusing.
 
Push-pull is also used to describe class B and AB amplifiers, which drive the output with 2 tubes or transistors in reverse polarity to each other - one side to handle negative swings, the other to handle positive.
 
Single ended is also used to describe class A amplifiers, which bias the tube or transistor so high, the sum of signal + bias never goes negative, so one device handles the entire waveform both positive & negative swings; it doesn't have pairs in reverse polarity.

 

[BassDigger]

  See this post from James Tanner:
 
http://www.head-fi.org/t/560499/new-headphone-amplifier-from-bryston/1590#post_11716014

 

Spoiler: Post from James Tanner:

Quote:

  Hi Folks,
 
I wrote this a while ago but it may help.
 

Is Your System Out Of Balance?​

 

One question which keeps coming up over and over is the controversy regarding audio components being "fully balanced" versus what is sometimes referred to as "balanced converting to single ended" at the input of the electronic component (preamp, electronic crossover, amplifier etc). The correct term for this balanced converting to single ended is more accurately referred to as "differential amplifier balancing" 

 

Popular mythology has seen fit to 'bless' the concept of 'fully-balanced' (meaning of course, two completely separate signal paths through a component, with its attendant doubling of parts cost and complexity, and halving of reliability). This approach completely misses the point, which is, of course, to eliminate hum and noise picked up by the audio cables feeding the component. 

 

The reason for this is that a differential amplifier, and this is -REALLY IMPORTANT- ‘rejects any common-mode noise’ which appears at its input, by a factor equal to its common-mode rejection ratio, (normally over 1000:1). A 'fully-balanced' circuit has a common-mode rejection ratio of precisely zero, since all signal, common-mode or not, is simply amplified and passed along via the two signal paths. It then remains up to the following component to attempt to reject that amplified noise, if it has a differential amplifier. 

 

Thus, fully-balanced circuitry is subject to passing along any noise which might be picked up on all the cables. Then it hits the final component in the system, usually the power amp, where the differential amplifier at its input is left to deal with the sum total of the common mode noise in the signal path, (multiplied by all the gain in the system).       I don't think this is an ideal scenario. If each component, (source, preamp, electronic crossover, power amp), had its own differential amplifier input, it would cancel any common-mode noise which appeared ahead of it, rather than amplifying it.  

 

 
james

 
To me, it seems to read like he's describing balanced line level connections, between electronic components, rather than the output topology of a headphone amp. (Or implying that this is the relevant/correct meaning of the phrase.)
 
Also, he doesn't seem to be advocating fully balanced as a preferable solution, unless I'm misunderstanding.
 
The rabbit hole continues to wind and turn! 

 

[Rob80b]

  See this post from James Tanner:
 
http://www.head-fi.org/t/560499/new-headphone-amplifier-from-bryston/1590#post_11716014

Not to be applied to balanced headphone cables
 
To quote myself.

  Balanced headphone connections and balanced interconnect connections should not be confused as they do not serve the same purpose, balanced interconnects as you've noted are used mainly to reduce noise though cancellation by incorporating a +  a - and a common ground. Headphones being a passive devise are more or less immune to noise due to grounding or RF signals and even very long runs of single ended headphone cables will not be inherent to induced noise, resistance and a change in impedance possibly and balanced headphones are powered with a left + and - and a right + and - signal and do not share a common ground and therefore totally discrete, ...........

 

[MRC001]

  Maybe I have misread you…but cannot sum neither the minus nor positive outputs from a balanced amp such as the BHA-1 as that would combine the left and right channels…. definitely a no no. The single ended out put comprises solely from the left + and right + and chassis ground…although one would get the same results using the left – and right – and chassis ground.

A headphone or speaker naturally responds to the difference between signal & ground. So it works the same way whether or not the incoming signal is balanced. If the incoming signal is unbalanced, the ground is in fact a ground, and if it's balanced, the ground is another signal that is the exact opposite of the + signal, but either way the difference between them is your musical signal.
 
Because the signal - on a balanced output is always the exact opposite of the +, you can simply ignore it and take the + alone. Doing so, you've converted balanced to unbalanced. Theoretically, nothing is lost, except the amplitude is cut in half (thus 6 dB quieter).

 

[Rob80b]

  A headphone or speaker naturally responds to the difference between signal & ground. So it works the same way whether or not the incoming signal is balanced. If the incoming signal is unbalanced, the ground is in fact a ground, and if it's balanced, the ground is another signal that is the exact opposite of the + signal, but either way the difference between them is your musical signal.
 
Because the signal - on a balanced output is always the exact opposite of the +, you can simply ignore it and take the + alone. Doing so, you've converted balanced to unbalanced. Theoretically, nothing is lost, except the amplitude is cut in half (thus 6 dB quieter).

Correct... but a balanced headphone output could also in theory reduce any inherent cross talk as there is no common ground to the drivers as there is with the single ended output.
 
BHA-1 outputs.

 
(The dual XLR 3 pin outputs  do show a common ground at pin 1 but again that is not used or shouldn’t be with the actual balanced headphone cable.)

 

[Rob80b]

Another consideration to keep in mind and may be beneficial to the very thin planar magnetic membrane and their quicker electrical response is if the amp in question is a full Class “A”, which produces a better linear output…. less crossover distortion of the reproduced/amplified waveform and constant standing current availability …unlike  Class A/B…..but.. class “A” amps like the Bryston BHA-1 can get a little toasty at times.
 
Class A
 

 
 
Class B

 

[CanadianMaestro]

This thread's turnin' into a Physics class.

 

[Rob80b]

  This thread's turnin' into a Physics class.

We'll switch over to "chemistry" and headphones later on this evening. lol

 

[CanadianMaestro]

^^ All for that, man. 

 

[ahnafakeef]

  Here's a link on balanced cabling:
http://www.headphone.com/pages/balanced-headphones-guide
 
In a nutshell, there is a larger voltage swing (output) with balanced, and better noise rejection.
 
Here's a link about tube vs. SS:
http://headphonehub.blogspot.ca/2013/03/pitfalls-of-vacuum-tube-amplifiers.html
 
Other headamps to browse:
http://www.enjoythemusic.com/magazine/equipment/1212/headphone_amplifier_shootout.htm
 
Hope these help.

Thanks a lot for the links, @CanadianMaestro. They were very informative.
 

 
The cheapest I have found is the Meier Corda Jazz. It is just an amp - no DAC. Costs around $400 when I bought it over a year ago. Its low price belies its absolutely excellent sound quality. Super clean, neutral, transparent, enough oomph to drive almost any headphone, with selectable gain (high/low) and it also has the best crossfeed circuit I've heard, which can be turned off if that's not your thing. It also has no potentiometer in the signal path, but a ladder stepped switch electronically actuated by an analog potentiometer that is not in the signal path. This is totally unheard of at its price range, providing perfect channel balance and the same transparent sound quality throughout the full range of the volume knob. Its sound compares with amps that cost several times its price. You can find reviews here on this site.
 
PS I just looked at Meier's site and the price of the Jazz has dropped to $340. He's based on Germany so we can thank Greece and the historically low value of the Euro vs dollar for that. Definitely fits the bill for "cheapest amp that will sufficiently power an LCD-2". More than sufficient.
 
PPS I have no business affiliation with Meier other than being a very satisfied customer.
 
PPPS Recommend way to get the most out of the LCD-2 or any good headphone, on minimum budget: make your DAC a high quality sound card (like an ESI Juli@), run sound card analog output to a Corda Jazz. Cost would be about $150 for the sound card, $350 for the amp, total $500 for a DAC and amp with great sound and that will let you listen to anything and drive almost any SE headphone.

 
Thanks for your valuable input, @MRC001

   
Wow! This thread's come alive!
 
My suggestion was going to be as Arnotts mentioned, the Gustard H10. It's not end-game, but it does work nicely with planar 'phones, like the LCD 2, and it's well made and excellent value for money.
 
It does frustrate me when people try to judge power requirements with simple maths and transducer sensitivity calculations. Yeah, sure, a few micro-watts will get the driver moving, and may be plenty loud, but an amp's main job is to control the driver, and for that you need good power. I've used the LCD 2's underpowered (but still many times what some are recommending), and whilst the sound was good, it really tightened up and gained some kick when I got the more powerful amp.
 
My suggestion would be 500mw minimum; this should have reasonable control, but you'd want more power at your next upgrade.
1 watt, as Audeze suggest, would be ok, especially if it's a transformer equipped tube amp; tubes have more flexible power delivery than SS.
2 + watts is plenty.
 
Also, the advice to concentrate on getting the best 'phones, for you, I agree with. You choose the amp to drive the phones. The phones are the thing that you actually hear; the quality, and characteristic, differences between different headphones are much more apparent than the differences between other components.
 
That leaves the DAC. Basically, my opinion is to just get the best that you can afford. The LCD 2's, as already mentioned, are perhaps an end-game headphone; they really will show the quality of whatever you have connected. And I mean that in ultimate terms. Yes, some phones do certain things better. But if you want reality and tonal purity, you can't get much better.
So, I'd spend more on the dac; the difference in tonal balance tends to be less, than amps or 'phones; you simply just get more of the music, the more you spend. And I'm an R-2R man; I'd definitely suggest the Gungnir MB, if your funds can stretch that far.
 
P.S. Don't go there; balanced, single-ended? That's just another rabbit hole...either will do. 

Thank you for your detailed response, @BassDigger
 
----------------------------------------------------
Now, after having processed all that information, I have a few questions, and some more assistance to ask of. Please note that I'm maintaining the end-game stance in the following opinions.
 
a) SS, tube, hybrid? No problem, since I'm leaning very much towards the Mjolnir 2 right now. Question - what's the difference between different tubes (LISST, 6B27 etc.) and which one(s) should I get?
 
b) As for the DAC, I'm leaning towards the Gungnir. Question - multi bit or standard Gungnir? I'm still confused as to what difference it makes in the ultimate sound quality.
 
c) Do I need an USB interface such as the Schiit Wyrd? It's $99, and I don't want to cut corners at this point.
 
d) Last but not least (in fact the most important), could I possibly get a better setup for my money instead of an LCD-2+Gungnir+Mjolnir setup? I've opened up a new thread here (http://www.head-fi.org/t/780582/best-summit-fi-end-game-setup-for-3000) in order to find out. So please provide me with your valuable input and help me reach a decision.
 
Thank you all very much for your kind cooperation. I really am grateful for your hospitality.

 

[jodgey4]

  Possibly….the Bryston BHA-1 in discussion does supply a discrete + & - signal in balanced mode to the headphone which could be beneficial to some headphone drivers.
I’ve only had my LCD2.2s for a short while but being planar magnetics they do appear to benefit the most from the balanced connection more than all my other previous dynamic headphones with added stage width and depth and possibly better base over the single ended connection.

I wonder if a single sided planar has the same results. Probably shouldn't, but it does make me wonder.
 

   

 Are we still down this rabbit hole?
But, does that mean that all balanced headphone outputs are push/pull?

 
Yup. NOPE. Rectangle/square thing.

  Maybe I have misread you…but you cannot sum neither the minus nor positive outputs from a balanced amp such as the BHA-1 as that would combine the left and right channels…. definitely a no no. The single ended out put comprises solely from the left + and right + and chassis ground…although one would get the same results using the left – and right – and chassis ground.

 
Yes you can sum them, by inverting the - into a +. Like I said, I'm not really sure what summing means or why it's used (if that's how they do it at all),,, but I'm told that's how most balanced amps with SE outputs work.
 
Also, you can connect the headphone cable shield to the ground pin1 on the 3-pin XLR balanced connector sometimes. Shouldn't really matter though because of noise rejection and sometimes weird ground loops.