question about Balanced signals.


I just purchased the Audio GD Vacuum HE1 MK3 which has true balanced design.  I have an amp, Rotel 1080RB that is also true balanced. 

my question is regarding sources? what if they only have SE output to the preamp SE inputs?  will I at least get some benefit of balanced signal from the preamp? 

@atmasphere Thinking of you :)  just read "why balanced?" on your website.  I need a pair of ICs since I traded in the integrated amp.  would be nice to know that XLR for under $200 would be better than same budget for SE.  Actually need two pair of balanced since my PS Audio Dac Jr has balanced outputs.  Speakers are Martin Logan ESL-X with a SVS micro sub (system total 6- 8" bass drivers)

dukebdevil

@dukebdevil If there is a 6dB increase in gain by going balanced, then the equipment does not support the balanced standard (AES48). The reason this is important has to do with your opening question about the best interconnect for the money.

If your equipment supports the standard then the interconnect will cease to be important. It will simply work and sound correct. And if the equipment supports the standard then there will be no 6dB gain increase as well.

There are three ways to do a balanced output: output transformer, a solid state circuit that can sink current and float at the same time, and the method we patented using a Circlotron. Inductive sources, like a phono cartridge are balanced sources. So think about this: if you apply a phono signal to the input of a differential amplifier, will it make a difference if one side of the signal is at ground? The answer is ’no’ the total Voltage is exactly the same whether one side is at ground or not.

A phono cartridge can meet all the requirements of AES48 as a result. Does this clear things up?

So with this all in mind, Mogami Neglex is a good balanced cable for not a lot of money (I use them in my home system) that will keep up with any high end audio balanced cable of any price so long as your equipment supports AES48. To me this is a big deal since high end audio cables can cost north of $1000/foot! My cables at home are 30 feet long and cost about $300/pair. If $1000/foot I’d be looking at $60,000!! For no difference in sound that’s pretty significant. Capishe?

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@atmasphere Thank you for the xlr cable suggestion.  I too like to save money and even if on short runs, an unbalanced cable is able to sound "clean", that cable is likely to be much more expensive to get similar performance to the balanced path.

audio-gd responded that "The preamp convert the SE input to balanced output.".  

without getting into the weeds, it seems there is one highly desirable outcome of balanced/differential circuits.  A balanced cable will have less noise, giving a higher signal to noise ratio.

@dukebdevil There are other advantages too- for example, differential amplifiers are more immune to power supply noise and they will have, in theory, a 6dB better noise figure than the same circuit executed single-ended. 

@atmasphere  sorry was trying to sum it up without going into details (because that is where we tend to make our technical mistakes).  In this last post, I should not have said "cable" .  As you clearly are aware, it is the whole design that contributes to less noise relative to signal (conversely higher signal to noise ratio).