Dante: We've all
heard of 'balanced' cables, being the ones with 3 wires, one more
wire than unbalanced. That's right isn't it? Well, yes
but there's more to it than that as
Music Manic raised the question 'Is there any benefit in using
balanced cables?' and GaryB took up the question:
GaryB: Basically a
balanced signal has a positive and negative conductor along with an
additional shield (earth ground). Unbalanced connections
combine the shield and negative together. An unbalanced cable
has two conductors, a balanced cable has three. Balanced signals
generally have less noise and isolating ground between two pieces of
gear is easier.
Typically most balanced audio signals are at a level called +4.
Most unbalanced audio signals are called -10 or -20. This is
about loudness measured in millivolts so obviously a +4 signal is
much louder. Audio loudness is expressed in decibels (dB) and
the scale is logarithmic. This is important for understanding
why the input level on the A16 might be low when receiving a signal
from an unbalanced device or why the signal from the A16 might be
hot going into a piece of unbalanced gear. It's not a problem,
just something to be aware of. Actually, the A16 Ultra has dip
switches to change levels for the first 8 channels and also the
second 8 channels, so it can have both levels running at the same
time depending on what it is connected to.
For a 1/4" phone cable end usually balanced is wired tip positive,
ring negative and sleeve shield or ground=unbalanced is tip positive
and sleeve negative/shield. There is no standard, however.