I thought the idea was that interference eliminated and that the transducers are floating
Headphones are always floating,
Are they ? Not ime unless we have a different understanding of the terminology
If so, what is the supposed advantage of that?Balanced headphones refer to headphones where the left and right drivers do not share a common ground. Right?
They use a 4-conductor cable and require an amp with isolated channels.
In practice (at least in my experience) good amps and headphones don’t sound better when using balanced drive.
Is this what the OP is speaking about?
You are right, that was not a correct choice of phrasing on my part. Typically one side of a headphone driver is tied to the circuit return, not floating.
What I meant to convey was that coil headphone drivers are intrinsically floating, they are not like e.g. an input on a bipolar device which has to be tied into the power supply to provide bias current. You do not have to tie one side of the headphone to circuit ground, or to any other power supply node, and unless you have a somewhat exotic driver like biased electrostatics, the headphones have no power supply, so there is no need to deal with inter-chassis currents, which is the primary advantage of a balanced interface between different pieces of powered equipment.
Without a path for common mode currents to flow, headphones do not have the big disadvantage that single ended line interfaces between chassis have, which is that the cable shield is carrying common mode currents (and thus having a common mode voltage impressed across it), and is also the signal reference. The reference side of the headphones should have no current flow, so no voltage drop, so no interference signal.
Because most amplifiers have an u balanced input. Making a balanced input for a guitaramp, especially tube amplifiers, costs money...I'd like to understand why we always tie one leg of an instrument (guitar, bass, etc) to ground.
A pickup is just a coil, just like a transformer, it would be a balanced source, why don't we utilize that and tie one leg to ground ?
We don't do that with microphones, why do we do it with instruments ?
Also goes for loudspeakers, headphones, just a coil, balanced connection, but one leg of the amp's output is always tied to ground.
Why is that ?
In a word, cost. To be more correct, historical cost. In the early tube days the only easy way to get any input or output balanced meant an expensive transformer. Use an unbalanced input and the transformer goes away, the build is easier and costs less. So two conductor connectors abounded, both the old screw type for microphones, RCA pin plugs, and the ubiquitous 1/4" phone plug. That's what early guitar connectors used, as the three conductor (microphone) connectors were really bulky in the pre-XLR days. Even XLRs are a bit bulky for a musical instrument.I'd like to understand why we always tie one leg of an instrument (guitar, bass, etc) to ground.
A pickup is just a coil, just like a transformer, it would be a balanced source, why don't we utilize that and tie one leg to ground ?
We don't do that with microphones, why do we do it with instruments ?
Also goes for loudspeakers, headphones, just a coil, balanced connection, but one leg of the amp's output is always tied to ground.
Why is that ?
Good question. Balanced headphones are promoted in consumer hi-fi world where a lot of principles get twisted and never critically examined or listened for…If so, what is the supposed advantage of that?
In theory, better stereo separation, better electrical damping, less dynamic sound compression, etc.If so, what is the supposed advantage of that?
Not necessarily..... and require an amp with isolated channels....
guitar amp inputs were connected to ground because the jacks were hard clamped mechanically to the chassis and the steel chassis was used as the ground plane. In order to isolate the input ground to say the reference of the input amp, they would have to have physically isolated the 1/4" phone jack at the input. That kind of jack was not readily available in the 40's-70's. Worse was the problem of no ground pin on the power cord. 3 prong AC outlets were not very abundant until the 80's and 90's. To make it worse, the 2 prong cords and outlets were not indexed, so a plug could be flipped over and plugged back in the same outlet. Which side of the plug was neutral was completely arbitrary. So the amp "ground" was just an arbitrary choice of AC power pole. You had to very carefully touch the mic with your hand on the guitar strings to find out if your amp just happened to be on the same AC polarity as the mic. If not then you got a shock. Better with your finger than your wet lips when trying to sing! I used to touch the strings to the mic and see if I saw a spark.I'd like to understand why we always tie one leg of an instrument (guitar, bass, etc) to ground.
A pickup is just a coil, just like a transformer, it would be a balanced source, why don't we utilize that and tie one leg to ground ?
We don't do that with microphones, why do we do it with instruments ?
Also goes for loudspeakers, headphones, just a coil, balanced connection, but one leg of the amp's output is always tied to ground.
Why is that ?
Good question. Balanced headphones are promoted in consumer hi-fi world where a lot of principles get twisted and never critically examined or listened for…
I don’t know any respected pro audio company making balanced headphones or amps.
Again, this is in regards to 4-wire headphone cabling, not balanced amp circuits.
They don't. Like everything else, they only care about the voltage across their two terminals. Balanced of course refers to symmetry of impedance not signal.Right - I could be persuaded that a 4-wire connection has some advantages - lower crosstalk between L and R is the easiest to quantify.
But 'balanced' - interpreted as meaning 'symmetrically driven' - is a little baffling. Why would a headphone drive unit care about the potentials of its + and - inputs with respect to an arbitrary 'ground'?
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