RE: soundcard with 8 output jacks

["Keith Doxey" <ukha@xxxxxxxxxxx>]

Hi John

>
> I didn't understand most of that Tim.  "4-pole"?
>

It refers to the number of segments on the plug.

Jack plugs normally are refered to as Mono (2 pole) and Stereo (3 pole)

As electronic equipment has become smaller there has been a need to cram
more connections into a smaller space. The 3.5mm "4 pole"
connector is a
bastardisation of the existing Mono and Stereo versions and was developed
for AV kit such as Video Cameras, portable DVD players and small displays.

For AV use, the 4 poles are used for COMMON (Ground), Left Audio, Right
Audio and Composite Video.

These connectors have now found their way onto multichannel sound cards and
rather than use 4  stereo sockets to output

Front Left and Right
Front Effects Left and Right
Rear Left and Right
Centre and subwoofer

they tend to do something like

3 pole socket - Front Left and Right
4 pole socket - Front Effects Left and Right AND Centre
4 pole socket - Rear Left and Right AND Subwoofer

thereby saving the space of one socket on an already crowded backplate.

Having explained that, its all academic anyway as your request was for a
card with 8 BALANCED outputs. The outputs from normal soundcards are
unbalanced.

Pre-empting your next question...

UNBALANCED is a normal type audio signal in which the signal is carried on
a
single wire with a ground return. These are fine for short distances but
over longer distances can suffer from piching up interference and can also
suffer "ground loop" problems which appears as a constant hum on
the signal.
Screened cable is required to carry unbalanced line level audio.

BALANCED is the type of signal used in the world of Professional Audio.
Instead of a single wire carrying the audio information, it is sent as two
signals of opposing polarity referred to as "+ve and -ve" or
"Hot and Cold".
At the receiving equipment the difference between the two signal will be
used to reconstruct the original signal. Any interference picked up along
the way will have been picked up equally on both wires so there will be no
difference hence it will not exist.
There is normally also a ground connection but this is purely for screening
the signal wires from interference, it doesnt carry any part of the signal.

Balanced lines have extremely high noise immunity and can travel for long
distanced on quite grotty cable although decent quality cable is to be
recommended :)

Balanced audio normally used two connector styles. By far the best is the
"XLR" connector which is a rugged latching 3 pin connector. Where
space for
connectors is more limited ajack plug can be used instead. This is normally
a 6.35mm (1/4") Stereo (3 pole) Jack referred to as TRS ( Tip - Ring -
Sleeve) describing the three segments of the plug body.

Depending on usage the connections are assigned as

STEREO JACK

Tip = Left
Ring = Right
Sleeve = Ground

BALANCED AUDIO

Tip = Hot +ve
Ring = Cold -ve
Sleeve = Ground

http://www.diyha.co.uk/electronics/stojack.html

Regards

Keith




** Sponsored by www.BERBLE.com **
all the Cool Stuff, in one Place