Hi,
I am trying to understand current flow in balanced and unbalanced headphones connection. I have read numerous articles on this topic and threads here but I am still wondering some things. Best article I found is this one: https://www.headphones.com/pages/balanced-headphones-guide. I also read this thread: https://www.head-fi.org/threads/con...lr-balanced-output-to-headphones-work.830205/. But I am still hungry for more info.
I would like to start with stuff that I understand:
Unbalanced connection with 3pin/TRS (amp) - 2x 2pin/TS (HPs) cable. There are two circuits (for left and right channels) with separate hot wires and common return wire.
Balanced connections for DACs/AMPs/etc. Each channel has two hot wires with reversed signal polarity and return wire. Receiving device has OpAmp that reverses reversed signal back to original. This leads to doubling the amplification power and cancels noise (as it is not inverted in any of hot wires).
What I don't understand:
Balanced connection od HPs to amp. I believe HPs are passive element and do not have any OpAmps to reverse signal. So it is like a simple circuit with amp and load (HPs). I read that advantage here is not having shared return wire for L and R channels. Why?
If I understand correctly, each channel is powered by two amps that produce inverted signals (thus wires ale also return ones for each other). But the reason for this is not noise cancelling but better performance of amps that do half of work each. Am I correct?
What about noise then? Let's focus on one channel. Let's say that one amp pushes 1V to a wire and another amp -1V to another wire. So voltage is 1V-(-1V)=2V. Will noises from both wires cancel or sum up? Let's say something produces 0.1V noise in both cables. Will those cancel from both cables [1V+0.1V-(-1V+0.1V)=2V]? Or add due to opposite flow direction of current in both wires [1V+0.1V-(-1V-0.1V)=2.2V]?
Another stuff I do not get is different number of pins in various cables. Aqudioquest Nighthawk has TRS to 2xTS cable. Sounds fine, it is simple unbalanced connection. Hifiman Arya also has unbalanced connection but with TRS to 2xTRS cable. What's the point of additional ring in 3.5mm jack plugs?
Similarly for balanced cables. Focal Clear has 4pin XLR to 2xTS while Hihiman HE-1000 uses 4pin XLR to 2xTRS. Again, why additional ring? It is even more complicated when i look into aftermarket cables. There are balanced cables offering TRRRS to 2xTS or TRRRS to 2xTRS. 4pin/TRRS to 2xTS sound reasonable to me. Two separate circuits for each channel with no shared wires. But I do not get idea of stuff like TRRRS to 2xTS or TRRRS to 2xTRS.
Hope someone is able to clarify this. I am really interested in how it works.
I am trying to understand current flow in balanced and unbalanced headphones connection. I have read numerous articles on this topic and threads here but I am still wondering some things. Best article I found is this one: https://www.headphones.com/pages/balanced-headphones-guide. I also read this thread: https://www.head-fi.org/threads/con...lr-balanced-output-to-headphones-work.830205/. But I am still hungry for more info.
I would like to start with stuff that I understand:
Unbalanced connection with 3pin/TRS (amp) - 2x 2pin/TS (HPs) cable. There are two circuits (for left and right channels) with separate hot wires and common return wire.
Balanced connections for DACs/AMPs/etc. Each channel has two hot wires with reversed signal polarity and return wire. Receiving device has OpAmp that reverses reversed signal back to original. This leads to doubling the amplification power and cancels noise (as it is not inverted in any of hot wires).
What I don't understand:
Balanced connection od HPs to amp. I believe HPs are passive element and do not have any OpAmps to reverse signal. So it is like a simple circuit with amp and load (HPs). I read that advantage here is not having shared return wire for L and R channels. Why?
If I understand correctly, each channel is powered by two amps that produce inverted signals (thus wires ale also return ones for each other). But the reason for this is not noise cancelling but better performance of amps that do half of work each. Am I correct?
What about noise then? Let's focus on one channel. Let's say that one amp pushes 1V to a wire and another amp -1V to another wire. So voltage is 1V-(-1V)=2V. Will noises from both wires cancel or sum up? Let's say something produces 0.1V noise in both cables. Will those cancel from both cables [1V+0.1V-(-1V+0.1V)=2V]? Or add due to opposite flow direction of current in both wires [1V+0.1V-(-1V-0.1V)=2.2V]?
Another stuff I do not get is different number of pins in various cables. Aqudioquest Nighthawk has TRS to 2xTS cable. Sounds fine, it is simple unbalanced connection. Hifiman Arya also has unbalanced connection but with TRS to 2xTRS cable. What's the point of additional ring in 3.5mm jack plugs?
Similarly for balanced cables. Focal Clear has 4pin XLR to 2xTS while Hihiman HE-1000 uses 4pin XLR to 2xTRS. Again, why additional ring? It is even more complicated when i look into aftermarket cables. There are balanced cables offering TRRRS to 2xTS or TRRRS to 2xTRS. 4pin/TRRS to 2xTS sound reasonable to me. Two separate circuits for each channel with no shared wires. But I do not get idea of stuff like TRRRS to 2xTS or TRRRS to 2xTRS.
Hope someone is able to clarify this. I am really interested in how it works.