SHOULD THERE BE A CENTER TAP on the secondary winding of a transformer to drive balanced or unbalanced audio line.?
For driving a balanced audio line a center tapped winding is not necessary. In fact a grounded center tap can cause ground loop problems and negate the advantages of the balanced line. I know this does not quite feel right but what happens is that the signal automatically “floats” and assuming the load is balanced it will automatically balance itself about ground. The point is that “ground” is not really defined and may have noise on it so it is not a good idea to try to force the signal to be referenced to it. Another advantage of not grounding a center tap is that If the load is unbalanced (i.e. one side is grounded) everything works and the source and load are still isolated from ground noise. The only situation where you need a center tap is when you are driving a push-pull amplifier stage where the grids of the valves need to be tied to ground. 12) I HAVE CONNECTED MY PHONO CARTRIDGE TRANSFORMER BUT I GET HUM It is usually because of a grounding problem. Click here for more inform
