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Originally Posted by Mediaogre /img/forum/go_quote.gif
Folks, I apologize if this is a little off-topic. I'm new to this tech and DIY sub-culture and I've heard this term used frequently. Would someone explain balanced to me in the context of cabling?
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Balanced has very little if anything to do with cabling, its about how signals are sent to the headphones. SE or single ended, has two channels (L+ and R+) with a ground for each channel (L- and R-). The signals go through L+ and R+ and a ground signal is sent through L- and R-. The ground signal is supposed to be as close as possible to a "zero" or some referred value from the design of an amplifier. For example, if you have an amp with a dedicated earth ground, it should be zero, but if you have a portable amp, your amp's design may set "ground" to say 0.1 volt or whatever other voltage may be easiest to work with.
On a balanced set up, you have 4 channels (L+,L-, R+, R-). The signals still go through L+ and R+ like in the SE setup, BUT the crucial difference is that the exact same signal but inverted is sent through L- and R-. So lets take for example a binary code of 1101101001010.
R+ = 1101101001010
R- = 0010010110101
and another signal would go through L+ and L- in the same way. The idea is if any noise disrupts R+, it would disrupt R- just as well. Since the signals are inverted with respect to one another, when they get to the headphone, the noise in R+ will cancel with the noise in R-. So the cables will pick up noise, but it will get rejected in how the signal is transmitted to the headphones. In addition since the signals are inverted with respect to each other, you end up hearing the difference between the signals and you end up getting some inherent amplification from a balanced configuration.
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| i'd like to see that, even insanely tight braids dont cross at 90 degrees (more like 75-80), close but no cigar. I would never use starquad either. if I cant run 2 twisted pairs in parallel and shield them from each other I tend to twist them VERY lightly, like once every 20-30cm the wires this way do not cross at all, but they do go parallel every now and then, which has its own effect, but is IMO the lesser of the 2 evils. all exposed wire cables are a trade off, you can trade one effect for slightly more of another. of course sometimes I o indeed do a round braid if practicality dictates this, but its not ideal |
I think we're talking about two things here. You're stating that the braids cross as 75-80 degrees, I think you're talking about the point where the two wires criss cross with one another. What I'm referring two with the signals being perpendicular is something like in this picture:
http://i373.photobucket.com/albums/o...les/KSC_04.jpg
Take a look at the black and take a look at the clear wires. Those are perpendicular to one another. In fact if you "debraid" the wires and allow the black wires and clear wires to go back together separately, what you get are two wires that are twisted together. So the "perfect solution" to the issue of two sets of two wires twisted tightly is actually a round quad-litz braid. In a quad litz braid you have 2 sets of wires, twisted tightly and connected together perpendicularly so that any interference from one channel will cancel out due to the nature of electromagnetic fields.
The angle you referred would be the angle between the signal and ground, which still exists in the twisted wiring method and any and all forms of starquad. If you take a look, starquad is very bad because the angle is very small (approx 15 degrees) so the signal and ground wires have more "contact" with one another. Versus say a VERY tight braid, you get a little bit more like 50 degrees. Then with a round quad litz braid, you get as you say something around 70 degrees. As far as I'm concerned, the round quad litz braid offers the best in terms of any geometry available out there with the exception of induction (starquads will always result in the least induction in wires because they will reduce the wire's diameter by the most).
