"TheKeith" writes:
I'm trying to figure this all out. Can someone explain it to me. This is
what I've figured so far, but I'm not sure if I'm correct. a TS (tip-sleeve)
plug can only carry a mono signal which is unbalanced correct?
Correct. It's only got 2 conductors.
A TRS (tip-ring-sleeve) plug is used to carry either a stereo signal
with two unbalanced mono channels in the tip and sleeve, or a
balanced mono channel (which utilizes both the tip and the sleeve
for the one channel of sound), correct?
Yup.
Now, can someone explain to me what unbalanced/balanced means and
also, what if would want to have a balanced stereo signal--is there
such a thing? is there no need for that? As you can see, I'm
confused. Help would be appreciated--thanks.
Unbalanced signals are single ended. There's a signal lead an a
ground.
Balanced signals use 3 conductors--a ground, a signal lead, and
another lead that carries the inverse of the signal (i.e. the signal
180 degrees out of phase).
The benefit of balanced lines is in noise cancellation over long runs
of cable--e.g. PA snakes carrying microphone level signals. Over
such a long run, a low level signal like that will get mixed with
plenty of 60Hz and 120Hz power line noise induced _common_mode_ (that
is, fairly equally across all 3 conductors). A preamp for a balanced
line uses either electronics or a transformer to do "differential
amplification" of the signal+ and signal- conductors. It amplifies
only the difference between those two lines. The beatuiful thing
there is that is amplifies the differential mode signal (since signal+
- signal- gives you 2*signal), and nicely
cancels out the common mode stuff (i.e. the 60Hz and 120Hz noise).
Feel free to ask followup questions. If you picture and draw you the
signal as a sine wave, and picture the "-" operation, you can envision
how a differential amp would squash common mode stuff, and amplify
differential mode stuff.
Best Regards,
--
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