Station 6 Preamplifier and Monitor Controller
20
Balanced cabling for instrument input
The balanced instrument/line input opens up the unique possibility to use a balanced configuration with instruments like
guitar, bass etc. The configuration will cancel out a large portion of the electrical noise induced in the cables. This is quite
advantageous when using long cables on stage or in an electrically noisy environment near light dimmers, high power
mains installations or nearby radio stations blasting megawatt into the air.
A guitar or bass hook-up is a high impedance system, and as such, it is very sensitive to electrical interference. Using a
balanced cable instead of a single core cable, introduces one additional wire to "receive" the environmental noise. This
additional noise signal is fed into the balanced input at the negative input terminal, canceling out the noise signal from the
positive terminal, all without affecting the sound signal from the instrument.
The configuration will in most cases give a substantial noise reduction, depending on the electrical characteristics of the
instrument pick-up. The negative and positive signal lines are terminated by different impedances at the instrument so a
total noise cancellation will not take place. The noise reduction is typically in the range of -15 dB to -20 dB.
Note that the noise from the instrument pick-ups is not reduced. Only the noise induced into the cable is reduced.
