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My Theory on Balanced vs Single Ended for High/Low Impedance Headphones - Page 3

post #31 of 92
interesting topic here. i always believed atleast the headphone to be balance itself to make the most differences really. i tend to think making a headphone balance dose offer bit better stereo separation and imaging ability personally. all balance is, is elimination of the common ground wire. i don't know why headphones use a common ground in the first place but anyhoo it's basically meaning the headphone this time has separate negative and positive for each channel. the negatives act as a ground as well so basically the headphone is double grounded, kinda like speakers. i guess you can consider speaker naturally balance cause they use separate negative and positive inputs on the crossover or whatever.

if i was using a balance headphone i would just use a preamp/power amp combo or integrated/receiver instead on the speaker outputs. that's only point and reason i see making a headphone balance besides better stereo separation. but who knows the stereo separation thing could be in my head but i do tend to feel making the headphone atleast balanced itself make biggest difference in the chain. getting a balanced source is pretty easy nowadays and not costly since most audio interfaces are balanced. just power amps and preamps are pain in the ass to find but i would only hunt those down if i was driving speakers at more then 100ft apart.
post #32 of 92

well most reasonably designed modern sources shouldnt NEED a preamp, so you are pretty safe there. also headphones/speakers dont know what the hell ground is, negative phase/ground..its all the same to them, well not so much the same to the crossover, but you very rarely/if ever see a symmetrically arranged crossover unless its active.

 

@ Chris, I know you know that mate, I just felt it needed to be stated clearly since its so often repeated around the net that balanced or bridged magically nets you 4x the power, with those 2 of course you have to consider whether the particular amp can actually put double the power into half the impedance. I feel saying that it can put double the power into double the impedance is a more accurate/safe assertion

post #33 of 92
Quote:
Originally Posted by RexAeterna View Post

i tend to think making a headphone balance dose offer bit better stereo separation and imaging ability personally.

The O2 can do -72 dB at 33 ohms load. "And that’s almost entirely caused by the 3.5 mm jack and plug."

For our hearing a much weaker channel separation is enough to make the sound appear completely on one side only.

post #34 of 92
Quote:
Originally Posted by qusp View Post


 

toying with the idea of an F6 headamp myself, but I shudder to think of the cost of the iron, at least the cost of the iron that I would accept.

on that note, since you are here Steve, any suggestions for high quality but not millio0n dollar tx for the F6? I dont mind spending say 3-400 for the pair

 

Well, that was a bit of an adventure.

 

Didn't know Nelson was working on an F6 so popped over to his forum at diyAudio and found the thread. Soon as I saw his teaser schematic I started scratching my head wondering how in the hell THAT was going to work. Wasn't until the 292nd post that Nelson finally confessed that he'd got the polarity dot wrong for the bottom winding on the secondary. tongue.gif

 

Nelson's using a Jensen JT-123-FLPCH which sells for just under $40. It's a 4 x 150 (Nelson said it was 4 x 600 but it's actually a 4 x 150) quadfilar line output transformer on a relatively small 50% nickel core. If you want something better than that, consider the CineMag CMOQ-1H. Don't recall the price off hand but I think they're around $65 each or thereabouts. They're built on a larger, 80% nickel core and mounted in a channel frame rather than PC mount. If you decide to go with those, when you order, ask David to mount them in the channel frame so the wires are coming out from the top rather than the bottom. That's what I prefer anyway. Makes it a bit easier for wiring things up.

 

Good luck!

 

se

post #35 of 92
Quote:
Originally Posted by Chris J View Post

 

Is this a current source with a really low output (i.e. bad) impedance or a voltage source with a really high (i.e. bad) output impedance?

An ideal current source will have an infinite output impedance,

An ideal voltage source will have zero output impedance.

 

 

Yes. biggrin.gif

 

Actually the F2's native output impedance is several hundred ohms. But Nelson put a 15 ohm resistor across the output to give it its 15 ohm output impedance. In that way, it's really no different than using a series resistor with a voltage source amp. In both cases the resistors are using up a fair amount of power.

 

se

post #36 of 92

thanks Steve, ha yeah I forgot to mention that, given it wasnt a complete schematic it had me scratching my head too as to what the 'secret' feedback mechanism might be. its pretty interesting regardless.

 

the jensens are probably fine, but I think I would feel better with something higher quality. I just know that it would be the first thing I would tweak and thus the jensens would just go to waste and the total money spent on the iron would be more than if I just buy something nice off the bat.

 

thats the way my justification process works anyway redface.gif


Edited by qusp - 8/6/12 at 9:08am
post #37 of 92
Quote:
Originally Posted by RexAeterna View Post

interesting topic here. i always believed atleast the headphone to be balance itself to make the most differences really. i tend to think making a headphone balance dose offer bit better stereo separation and imaging ability personally. all balance is, is elimination of the common ground wire. i don't know why headphones use a common ground in the first place but anyhoo it's basically meaning the headphone this time has separate negative and positive for each channel. the negatives act as a ground as well so basically the headphone is double grounded, kinda like speakers. i guess you can consider speaker naturally balance cause they use separate negative and positive inputs on the crossover or whatever.
if i was using a balance headphone i would just use a preamp/power amp combo or integrated/receiver instead on the speaker outputs. that's only point and reason i see making a headphone balance besides better stereo separation. but who knows the stereo separation thing could be in my head but i do tend to feel making the headphone atleast balanced itself make biggest difference in the chain. getting a balanced source is pretty easy nowadays and not costly since most audio interfaces are balanced. just power amps and preamps are pain in the ass to find but i would only hunt those down if i was driving speakers at more then 100ft apart.

 

This is similar to the "speakers sound better if they are bi-wired" argument.

Personally, I don't see any advantage or disadvantage to sharing the ground in headphones.

The ground wire normally has a much lower impedance than the output impedance or load impedance, i.e. any effects of the ground wire impedance would be swamped out by the output impedance and load impedance interaction. 

 

A loudspeaker is not naturally balanced.  Headphone drivers and speaker drivers are no more inherently balanced than a resistor or a capacitor or an inductor is inherently balanced or SE, in other words, they aren't.  They are merely two terminal devices.

post #38 of 92

Chris, not in the amps i'm using, a loosely fitting phono and a couple meters of wire would swamp another channel in series. my main point though is that many amps are so lowZ that doubling it is not going to have any effect


Edited by qusp - 8/7/12 at 6:16am
post #39 of 92
Quote:
Originally Posted by Chris J View Post


A loudspeaker is not naturally balanced.  Headphone drivers and speaker drivers are no more inherently balanced than a resistor or a capacitor or an inductor is inherently balanced or SE, in other words, they aren't.  They are merely two terminal devices.

 

So then how are you defining "balanced"?

 

se

post #40 of 92
Quote:
Originally Posted by qusp View Post

Chris, not in the amps i'm using, a loosely fitting phono and a couple meters of wire would swamp another channel in series. my main point though is that many amps are so lowZ that doubling it is not going to have any effect

 

Mr Q.

I was assuming a typical headphone amp, an output impedance of a few ohms.

But if you got an ultra low output Z amp...........................Bob's yer uncle.

And since you are from the Commonwealth, I can use strange phrases like "Bob's yer uncle"!

Chris

 

Quote:
Originally Posted by Steve Eddy View Post

 

So then how are you defining "balanced"?

 

se

 

depends on what you are doing with it.

How can you say "this headphone driver is balanced?" "This loudspeaker system is balanced"?

The inverse is also true, you can say it is neither balanced or unbalanced.

It is a floating, ungrounded, two terminal device.

You may drive it with a balanced or unbalanced signal, it does not matter to the headphone driver i.e. the speaker.

post #41 of 92
Quote:
Originally Posted by Chris J View Post

 

depends on what you are doing with it.

How can you say "this headphone driver is balanced?" "This loudspeaker system is balanced"?

The inverse is also true, you can say it is neither balanced or unbalanced.

It is a floating, ungrounded, two terminal device.

You may drive it with a balanced or unbalanced signal, it does not matter to the headphone driver i.e. the speaker.

 

A loudspeaker system is a bit different animal as the crossover networks are not typically implemented as balanced. We're just talking headphone and loudspeaker drivers.

 

So I go back to my previous question, how are you defining "balanced"?

 

se

post #42 of 92
Quote:
Originally Posted by Steve Eddy View Post

 

So I go back to my previous question, how are you defining "balanced"?

 

se

 

in simplest terms

Quote:
a floating, ungrounded, two terminal device

this^

post #43 of 92
Quote:
Originally Posted by Chris J View Post

 

Mr Q.

I was assuming a typical headphone amp, an output impedance of a few ohms.

But if you got an ultra low output Z amp...........................Bob's yer uncle.

And since you are from the Commonwealth, I can use strange phrases like "Bob's yer uncle"!

Chris

 

 

depends on what you are doing with it.

How can you say "this headphone driver is balanced?" "This loudspeaker system is balanced"?

The inverse is also true, you can say it is neither balanced or unbalanced.

It is a floating, ungrounded, two terminal device.

You may drive it with a balanced or unbalanced signal, it does not matter to the headphone driver i.e. the speaker.

 

hahaha, you are right, the odd person actually does say that down here, but around here only for comedy.

 

yep all 3 amps i'm using at the moment are lowZ, the lowest 12.5 mOhms and the highest ~30 mOhms. I think you would agree doubling that is of no consequence. I use multidriver IEMs a lot and they thrive on these amps

post #44 of 92
Thread Starter 
Quote:
Originally Posted by Steve Eddy View Post

 

So then how are you defining "balanced"?

 

se


I'm sticking my nose in here but I believe some hifiman and audeze headphones offer a fully balanced design with a separate ground that runs all the way to the drive unit.

 

But other than that speakers and headphones are by and large not balanced I would say - their amp and source can be balanced but if there is no separate ground running all the way to the drive unit it's hard to really call it a *fully* balanced system.

 

On the other hand it may not matter that much if the headphone is balanced or not - the wire goes in and the wire goes out. The amp will know what is a "balanced ground" and let the driver return to this neutral state when no signal is fed.

post #45 of 92

Ok, simply put, balanced means equal impedances with respect to a reference point which is typically, but not always, ground.

 

The voice coils in a loudspeaker or headphone driver are typically symmetrical which makes them inherently balanced. Same with the windings on an audio transformer for example. The reference is the center of the winding. It doesn't matter if there's not a physical center tap to force balance. If the windings are symmetrical, it's balanced. Period.

 

se

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