Lawrence Leung wrote in
:

"Uptown Audio" wrote in
:

styles) of RCAs. Much gear that accepts balanced cables is not really
fully balanced and the use causes as much internal noise from the
conversion stages as any noise rejected. In that case a good SE
connection is actually best. You will notice different gain specs on
many amplifiers with the use of balanced vs single-ended connections
to make the point of more circuitry being implemented vs less. The
only way to tell for sure is to connect both types of the same cable
material and listen. I doubt that you will notice any differences
either way unless there is a big amplifier gain issue there. I have

There is a contradiction of your statement, if the component circuitry
is not a balanced one, you won't be able to hear the difference
anyway. But if there is a balance circuitry inside, and sure you will
tell the difference. And I doubt that too many gear(s) that accept
balanced cables (assume they will say balance input/output) does not
really has the balance circuitry, that considered as fraud and can get
sue for that!

I'm curious what is meant by 'balanced' in the context of consumer audio
equipment. Is it differential output and differential input, or is it
just a pretty connector that's there to hype the product, or is it
something in between. The cable/connector by themselves doesn't make it
a balanced circuit or a balanced transmission line.

Here are some possible amplifier configurations. If you can't see them,
use a fixed pitch font on your reader. The thingies are connectors,
the 'V' is a ground connection. A 'o' on a signal means inversion.

_____ cable _____
| |------------| |
| PRE |o----------o| POW |
|_____| |_____|
| |
|------------------|
V V
A. This is the ideal setup - differential output and
differential input. Very good common mode rejection,
truly balanced.

_____ _____
| |------------| |
| PRE | +--------o| POW |
|_____| | |_____|
| | |
|-----+------------|
V V
B. Not bad - single-ended output and differential input.
Not truly balanced but still has good gommon mode
rejection.

_____ _____
| |------------| |
| PRE | +------+ | POW |
|_____| | | |_____|
| | | |
|-----+------+-----|
V V
C. Might as well not bother. SE output and
SE input.

Which of the above are we talking about? The whole reason for using a
balanced distribution scheme is to get rid of common mode noise (i.e.,
hum). It won't improve the signal in any other way.

It's easy enough to do a differential input circuit, and it wouldn't
surprise me if some high end equipment has differential intputs. An op
amp or a pair of transistors, or if you're really feeling silly, a twin
triode will do the job. I'm inclined to believe that example B is the
more common 'balanced' output, though.

-- J