[paradoxper]

It's just curious how many different interpretations of balanced there are. And semantics kind of seems to be at play here.
 
For example, Single ended amplifier providing differential output, is, well, balanced, correct? However, semantically it's not a "TRUE" or "FULLY" balanced design because it doesn't have 2x the circuitry? 
 
But hasn't 2x the circuitry always just been a bridged design? Contrary to that is circlotron topology which is inherently balanced. 
 
Further thought per balanced: 
 
Jason Stoddard:
 
 

is balanced gear simply converting the inputs to single-ended? Or is it creating the differential signal with a separate gain stage after the main one? There are a bunch of ways to do it wrong. Real balanced gear is differential all the way through without splitters and summers and other band aids. This means among other things a more complex gain stage, 4-gang pots and 4-pole input selectors. It's worth it though not just for the elimination of ground current effects but for common-mode noise cancellation - very very nice for headphones."

 

[Steve Eddy]

If that were true, this wouldn't be such a discussion.  It's all about semantics and who can use which term and who can't.  Those are things usually decided by a standards committee and even then, it doesn't mean the industry will follow.

There is only "such a discussion" because of naïveté.

Doug's background and experience is law (he has a Ph.D.). Not audio.

I've no idea what your background is, but other than a few years when I earned a living in the computer industry, I've been involved in the audio industry one way or another for over 30 years. And I know what the quintessential definition of "balanced" is in the industry.

You just called it inferior.  He didn't.  He called it a design choice and implied nothing of the sort about one being inherently inferior vs. another.

I just called it what it is. A proper balanced amplifier, not a bridged amplifier that is erroneously called "balanced."

se

 

[Steve Eddy]

This thread seems to be arguing that the definition of balanced is only applied to cables.  That's completely failing to recognize the possibility of a new application to that definition.  It's like creating a rule that no one can discover an expanded application principle, because the original definition doesn't allow it.

It's not about failing to recognize the possibility of a new application to that definition. It's about people not knowing any better and misapplying terminology that has been well established and well defined for many decades.

Doug for example was using "balanced" and "differential" interchangeably when they are two different things. As I said, his background and experience is law, not audio and electronics.

The analogy is understood only if you consider than an amplifier has entered the arena of the cable.  To keep the signal balanced and to use common mode rejection within the amplifier itself, then the amplifier circuit must be duplicated just as the cables are.  Once the cables are separate, the balancing holds true.  However, introduce an amplifier into that signal stream where the signal is no longer separated, then it's no longer balanced.  If the amplifier also imparts some noise you're trying to remove, then the advantage is lost ... unless you have two circuits that continue to keep the signal separated ... as in two sets of tubes, for instance.

What's your background and experience with regard to audio and electronics? Do you know what you (think you) know just from hanging around on forums on the internet?

se

 

[tomb]

Perfect. Now we get personal.

 

[Steve Eddy]

Perfect. Now we get personal.

Call it what you will. There are people throwing out a lot of words and making a lot of arguments. From my perspective, they are not terribly well informed arguments. So I think it would be useful to know the perspectives of those arguments.

Without Googling, can you tell me what AES stands for and give a brief description of it?

se

 

[kevin gilmore]

actually from what I think I was told, doug has both a Ph.d and a Jd.
 
and alex has a Ph.d in physics.
 
neither of which means anything.
 
I will point out something that some probably have missed.
 
Lets say you want to make 2 amplifiers, both output the same voltage levels.
 
one is a single ended amplifier, and the power supplies are +/-60 volts
(I guarantee that this amplifier will make your head explode)
 
the other is a bridged output amplifier and the power supplies are therefore +/-30 volts
(This amplifier will also make your head explode)
 
with respect to the load, the headphones, the voltage level is going to be the same.
The difference is that you could pick different transistors for one than the other and
in the gain stages of these amplifiers lower voltage transistors could perform very
differently from higher voltage transistors. Higher Ft, lower capacitance etc.
 
Now practically both of these amplifiers are likely massive overkill.
(unless you have He6 or K1000)
But a bridged amplifier that runs on +/-15v  (your very typical power supply)
would perform the same as a single ended amplifier on +/-30V
And this definitely effects the cost of the amplifiers in a big way.
 
The eddie current balancing amp has only 2 input terminals, neither of which
are ground. In fact the common mode voltage the transformer can handle
is likely 100 volts or more. So you have to say that this amplifier has
a differential input.  What's on the other side of the input transformer is
something completely different and is a single amplifying device driving
a transformer, whose output can be differential if that is what you want.
 
 
Now a different amplifier might be 2 amplifying devices In push pull.
The sound will be very different, the rise and fall times would be very different
etc.

 

[Steve Eddy]

The eddie current balancing amp has only 2 input terminals, neither of which are ground. In fact the common mode voltage the transformer can handle is likely 100 volts or more. So you have to say that this amplifier has a differential input. 

More germane to this discussion, it has a balanced differential input.

se

 

[dsavitsk]

And semantics kind of seems to be at play here.

Ya think?

I don't know what's with the ad hominem.

I generally use the term differential to distinguish a circuit that is balanced from front to back from one that has balanced inputs only. But balanced is also fine as it is simply short for balanced circuit, and it is used by many in the industry to describe such circuits. For better or worse, language evolves and the definition has changed.

 

[Steve Eddy]

I generally use the term differential to distinguish a circuit that is balanced from front to back from one that has balanced inputs only.

"Differential" is not a good term to use to describe what you're trying to describe because a differential circuit may be operated balanced or unbalanced.

Take your basic long tailed pair differential circuit. Tie one of its inputs to ground. The circuit still functions differentially, but it's not balanced.

But balanced is also fine as it is simply short for balanced circuit, and it is used by many in the industry to describe such circuits. For better or worse, language evolves and the definition has changed.

But the definition has not changed. Balanced still means what it meant many decades ago. A balance of impedances, fundamentally for the purpose of common mode noise rejection.

Differential is not synonymous with balanced however. Differential may be implemented balanced or unbalanced. The unbalanced RCA inputs on the majority of amplifiers out there are driving differential input circuits.

Yes, Victor over at BAT uses balanced differential circuitry from input to output, but that does not mean every instance of a differential circuit is balanced. In fact the vast majority are not (for example, every unbalanced input that's driving an opamp is driving a differential circuit).

So we've come full circle. The problem is still people using terminology they don't have a good understanding of which just creates a lot of confusion for anyone who is trying to understand it.

se

 

[purrin]

I jokingly blamed Tyll about a year ago for all this confusion on "balanced" terminology. Tyll replied with two middle finger smileys. I thought that was cute.

 

[Steve Eddy]

I jokingly blamed Tyll about a year ago for all this confusion on "balanced" terminology. Tyll replied with two middle finger smileys. I thought that was cute.

Ha!

Yeah, in spite of all that he's wrought, I like Tyll. He's like a big teddy bear in a Hawaiian shirt.

se

 

[Armaegis]

Everything is balanced until you tie one end of it to ground. But good thing ground is always a nice stable point that doesn't ever deviate or is susceptible to noise right guys? ... guys?
 
 
 
/nothelping

 

 

[Steve Eddy]

Everything is balanced until you tie one end of it to ground. But good thing ground is always a nice stable point that doesn't ever deviate or is susceptible to noise right guys? ... guys?

Not terribly difficult to achieve, until you start slapping 3 pin IECs on everything, then all bets are off.

That third pin is the single leading cause of ground loops and noise in audio systems. And it doesn't help that a lot of people think that it is "ground" and somehow has some relevance to the proper grounding of an audio system.

I've known people who have pounded dedicated ground rods into the dirt outside their listening rooms so that they could tie this "ground" to it and achieve a much quieter audio system.

se

 

[kevin gilmore]

I've known people who have pounded dedicated ground rods into the dirt outside their listening rooms so that they could tie this "ground" to it and achieve a much quieter audio system.

se

i am one of those people. and a massive 10kw isolation transformer in addition

after 1 foot of dirt, pure clay. its a great ground


then there is the whole issue of satellite boxes and display devices.
only way is an optical path from the satellite box.

 

[money4me247]

Not terribly difficult to achieve, until you start slapping 3 pin IECs on everything, then all bets are off.

That third pin is the single leading cause of ground loops and noise in audio systems.

3 pin refers to the socket build into the amplifier? or are we talkin abt the 3 pronged male end of the power cord?