Re: Balanced vs unbalanced

[Keith Doxey <ukha@xxxxxxx>]

Quoting tannedblondbloke <tannedblondbloke@xxxxxxx>:

> While surfing on a number of HA sites, I have come across various
> references to balanced, as opposed to unbalanced, in the context of
> line level audio leads.  Unbalanced tends to be standard RCA audio
> interconnects and balanced tends to be CAT5E.
>
> May I ask what the difference is please?

As already answered by others,

Unbalanced - a single conductor carrying the signal using ground as the
return
path. Can suffer from induced noise as well as "ground loops"
which can occur
when the source and destination equipment are both earthed and are on
different
or distant mains supplies.

Balanced aka Differential - two conductors carrying equal but opposite
polarity
signals. The difference (DIFFERENTIAL) between the signals is the active
signal
free of noise. Any noise introduced is introduced equally (BALANCED) onto
both
wires so the difference is zero. [Consider the effect of adding 1kg to each
side of a set of balance scales- makes no difference, which ever side was
heavier is still heavier.]


> When would you use one rather the other?

Unbalanced for short links with screened cable on domestic equipment.

Professional equipment almost always has balanced inputs and outputs anyway
so
is almost always connected via balanced lines

Balanced for long links on twisted pair cable.

> How do you convert from on to the other?

<MODE = BIASED>
Easy --- KAT5  http://www.kat5.tv   :-)
</MODE>

> I understand why it's easier to wire the house with CAT5E, and why the
> twisted pair maintains signal purity, but why wouldn't you send
> unbalanced through CAT5E?
>

Bacause CAT5 cable is twisted pair optimised for the distribution of
balanced
line signals. It is largely unsuitable for unbalanced signals because these
tend to be low level and subject to interference because CAT5 is not
screened.

Hope that helps

Keith

www.diyha.co.uk
www.kat5.tv

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