[mcandmar]

I found when using a "balanced" output from a transformer output tube amp, i.e. the output transformer is center tapped and providing a + and - feed to each driver, the low end sounds better controlled, or more technically correct i should say it sounds better damped.
 
As for a true differential path from DAC's to amplifiers to the output stage, keep in mind you are doubling the amount of components in the signal path, hence the argument it can increase distortion is somewhat valid.

 

[Steve Eddy]

I found when using a "balanced" output from a transformer output tube amp, i.e. the output transformer is center tapped and providing a + and - feed to each driver, the low end sounds better controlled, or more technically correct i should say it sounds better damped.

Um, how exactly do you connect the center tap to the drivers?

As for better damped, the output transformer is going to have a relatively high output impedance, which works against damping.

As for a true differential path from DAC's to amplifiers to the output stage, keep in mind you are doubling the amount of components in the signal path, hence the argument it can increase distortion is somewhat valid.

But the funny thing is, most "balanced" headphone amps aren't differential. They're just bridged pairs of amplifiers.

se

 

[Steve Eddy]

All I mean is that any noise that is present in the room is just going to be picked up by whatever is single ended. If the system isn't fully balanced, then the system is susceptible to noise, but not the balanced parts. Saying that it is "undone" was definitely the wrong word.

But of course you're rarely going to have any noise issues even if the system is all unbalanced.

I have been reading about all of the ways phone companies pioneered audio, including making PCM widely used and such. I wasn't aware that they invented balanced systems either. Thanks for the history lesson. I have also seen the horrible balanced implementations you're talking about. It is pretty strange what people will do to call a system balanced.

Yeah, PCM was first conceived at Bell Labs back in the 1940s. Of course it took a while before any practical implementation, but they were always thinking long term. Check out the book The Idea Factory: Bell Labs and the Great Age of American Innovation. It's amazing the things that came out of Bell Labs that are an integral part of our lives today.

se

 

[sludgeogre]

 But of course you're rarely going to have any noise issues even if the system is all unbalanced.

Yep, as far as I understand, you're certainly correct. Unless you live in one of those "haunted" houses you see on ghost hunter shows where they run around measuring "impossible" electromagnetic fields. Damn ghosts hate electronics and audiophiles!
 

 Check out the book The Idea Factory: Bell Labs and the Great Age of American Innovation. It's amazing the things that came out of Bell Labs that are an integral part of our lives today.

Thanks for the book recommendation, that sounds really interesting. I'll have to check it out. It would probably be a much easier way of learning how these technologies started and work than reading forums, Wikipedia, and as many scholarly articles as I can interpret with my lack of electrical knowledge. 

 

[mcandmar]

Um, how exactly do you connect the center tap to the drivers?

As for better damped, the output transformer is going to have a relatively high output impedance, which works against damping.
But the funny thing is, most "balanced" headphone amps aren't differential. They're just bridged pairs of amplifiers.

se

The center tap is connected to ground instead of the bottom tap position, so have you a + and - either side of signal ground vs grounding the lower tap (usually black) and taking the + off the top of the windings.

 

[Steve Eddy]

The center tap is connected to ground instead of the bottom tap position, so have you a + and - either side of signal ground vs grounding the lower tap (usually black) and taking the + off the top of the windings.

What's the bottom winding on the primary tied to? Are we talking single ended or push-pull?

se

 

[mcandmar]

In my case single ended, but i dont see why the same cant be done with a push-pull.  For example in this schematic instead of grounding the blue wire and using the 8ohm tap, ground the green center tap and use the red/blue as your +/- output.
 

 

[Steve Eddy]

I'm still not understanding why you need to ground the secondary's center tap. Is that for safety reasons or something?

se

 

[bufferoverflow]

@ Steve Eddy :
Are you sure you have not fallen victim to the amp-manurefacturers marketing mumbo-jumbo regarding 'balanced' headphone-amps ?
It is not the same as the 'balanced' we know from pro-audio cable-runs, but that IS what they want the consumer to think .
(it just may, in some cases, be measurable (or perhaps even audible) that the 2 channels don't share the same wire)

 

[Steve Eddy]

@ Steve Eddy :
Are you sure you have not fallen victim to the amp-manurefacturers marketing mumbo-jumbo regarding 'balanced' headphone-amps ?

Oh, absolutely. For years I've been pointing out that such amps should more appropriately be called "bridged" rather than "balanced." Though there are in fact balanced amps out there that have balanced differential inputs but they seem to be in the minority. And even in traditional high end audio there has been a lot of confusion and misinformation regarding "balanced" with many believing "balanced" is done by providing two separate signal paths for positive and negative (i.e. not differential and not capable of common-mode rejection).

It is not the same as the 'balanced' we know from pro-audio cable-runs, but that IS what they want the consumer to think .

I don't know if that's what they want the consumer to believe (in some sort of nefarious way) or if they just don't know any better themselves. My hunch is the latter.

(it just may, in some cases, be measurable (or perhaps even audible) that the 2 channels don't share the same wire)

The two channels share the same wire? What, you mean at the headphone jack?

se

 

[castleofargh]

Steve Eddy favors SE, while nigeljames from Birmingham likes Balanced.
 
I see the pattern!!!!!
 

 

[nigeljames]

  Steve Eddy favors SE, while nigeljames from Birmingham likes Balanced.
 
I see the pattern!!!!!
 

 
Damm we have been sussed.

 
Seriously though I don't prefer balanced to single ended. I wanted the best Sabre32 DAC I could find within my budget which I decided was the NFB-7.
 
It is a balanced DAC so I wanted to max it's potential with a balanced amp.
 
If I heard a better sounding single ended DAC/amp within my price range I would have no issues with purchasing.

 

[Steve Eddy]

Steve Eddy favors SE, while nigeljames from Birmingham likes Balanced.

I see the pattern!!!!!
 

Oh no.

WE'RE ALL GONNA DIE!!!!!! AYYYYYEEEEEEEE!!!!!!

se