"Eeyore" wrote in message
...


David Looser wrote:

It's not necessary to go to full balanced to get over earth loop
problems,
differential inputs connected to unbalanced outputs achieves the same
thing.

An unbalanced output with equal value resistors in the hot and cold signal
lines
( the cold going to equipment ground ) and a seperate screen IS balanced.

Balanced in terms of impedance, not balanced in terms of signal voltage (and
hence it's ability to cause crosstalk in adjacent circuits). So I don't
think it correct to say it IS balanced. Having said that it is a perfectly
satisfactory arrangement for short runs and one I have used often.

Normally just called 'impedance balanced' it provides almost all the
advantages
of full-blown active balanced outputs. With a few more resistors it can
even
'ground sense' and overcome hum caused by non-equipotential equipment
grounds.

Not quite sure what you mean by that, a differential input naturally
overcomes hum caused by non-equipotential equipment grounds. This was made
very evident when a piece of video equipment of mine which has a
differential, unbalanced 75R co-ax input was fed from a video line which,
due to confusion about which is the neutral and which the earth pin on an
EP4 mains connector, was referenced to mains neutral, not earth. The
equipment worked fine with but the merest hint of a hum bar on the picture.

A differential ( balanced ) input takes a couple more resistors to make
than an
unbalanced one.

Indeed.

PLUS the XLR is an excellent connector compared to the RCA.

True, though a lot bigger and more expensive.

David.