Someone feel free to correct me, but this is what I have been led to believe
on the subject.
A "normal" mono cable has two conductors: Ground and Hot, essentially. The
signal is the difference between the two.
What makes a cable Balanced is an extra conductor. This is the same as the
"hot" signal, above, but inverted, i.e., 180 degrees out of phase.
To create a balanced signal from an unbalanced one, accurately invert a copy
of your signal and send it down a second conductor!
The idea behind balanced cables is that you send the exact same signal down
the wire, one copy inverted, and then on the other end, re-invert the
inverted one and sum the two together. What this gives you is less
interference. Why? Because if some noise enters the cable along the way
through induction, it will affect both signal lines fairly equally. When
they are restored and summed at the destination, the "noise" will be
cancelled because it will not be out of phase from one conductor to the
next.
Most XLR connections are balanced, BUT NOT ALL. As far as I know, XLR cable
is XLR cable, but what the devices on each end are DOING with those three
conductors may vary, especially in homebrew stuff. With microphones, the
third conductor may be phantom power, not a balancing connection.
1/4" balanced using TRS is essentially just using a stereo cable. I HAVE
seen TRSSS (5-conductor) stereo balanced 1/4" cables a few times over the
years! It is not common. Pros tend to use two XLR ("Cannon") cables instead.
Hope this helps.
-----Original Message-----
From: Tentochi [mailto:
tentochi2003@...]
Sent: Tuesday, 29 October, 2002 2:41 PM
To: MOTM listserv
Subject: [motm] [Q] Balanced vs. Unblanaced
I need some clarification on balanced vs. unbalanced
connections.
Normal instrument (1/4") cables are mono and
unbalanced, correct?
Normal balanced cables are mono and are the same as
unbalanced stereo 1/4" cables (TRS), correct?
So therefore, there is not such (normal) thing as a
balanced stereo cable, correct?
How do you convert an unbalanced 1/4" cable/signal to
a balanced 1/4" signal?
How do certain processors and mixers differentiate
between the two when only one jack is present?
Are all XLR cables balanced?
Can you have a stereo XLR cable? If so, is it common?
Is there anything else I should know in this arena?
Thanks!
Shemp ("The Unbalanced Stooge")