Music Manic:  I think I've been running my Sherman Filterbank too hot. I'll set the DIP to unbalanced. My crimson EQ 301 is balanced so that's fine. I'm not worried about the unbalanced cable for the Sherman because it's half a foot long. There's no improvement for a pseudo balanced cable is there?

GaryB: There might be.  Generally it's not worth worrying about unless there's a ground loop that can't be eliminated.  Yes, balanced signals can travel a long way, but unbalanced cables should be kept to about 20'.

Immanuel: I believe the signal is still balanced when setting the DIP switch to -10.  It is just less loud.  By the way a connection between two devices is only actually balanced if the sending device, the receiving device and the cable are balanced.

GaryB:  That's true but you can run the shield from the balanced connection only up to the unbalanced end and that is almost as good (floating the shield).  It takes a special cable that the engineer needs to wire himself, so most times, it's not worth bothering with.  It IS one way to kill a ground loop though.  Otherwise most balanced devices can just short the negative conductor to the shield and run as though unbalanced.

Music Manic: I've set half of the I/O to +4 and the other to -10. I find the output of the Sherman filterbank overloads the -10 input because of the harmonic distortion  So I think I'll send the return to the balanced part of the A16.  Is it just relative to voltage when it comes to balanced/unbalanced signals right?  The cables either way are tolerant of all voltages aren't they and impedance won't really matter will it (if an unbalanced signal feeds a balanced one) ?

GaryB:  Well it's all line level.  There are two main standards for 'line level' audio (Google 'line level' if you want to know more).

Professional audio +4 dBu 1.228 1.736 3.472
Consumer audio −10 dBV 0.316 0.447 0.894

Both are represented by very small voltages.  There's no danger to equipment possible from a mismatch other than a blown speaker if the level was turned up and the system was expecting consumer level and it was pro level instead.  Neither is really better except that the balanced lines in most +4 gear allow a little cleaner signal and longer runs without loss of fidelity.

The reason that consumer stuff is unbalanced is because it's simpler and consumer stuff gets connected to mostly known products made to similar specs.  In a professional environment there are custom one-offs and strange units from other lands being used together.  Grounding schemes are not always the same.  Also cable runs tend to be much longer.  In a real studio there are hundreds and hundreds of feet of cable.  Maximum protection from interference is needed on each cable.

Remember, RCA outs are unbalanced -10.  XLR outs are +4 balanced.  Nothing will explode if you start with the speakers turned down.

GaryB and PlanetZ Members October 2014