Quote:
Originally Posted by Matt Syson  Hi
The situation of having a grounded centre tap is entirely different compared to a non grounded centre tap. When it is not grounded you have a series circuit where the voltage the primary 'sees' is simply double the voltage from one amplifier output. To do otherwise contradicts basic laws of electricity as it is a series circuit, the current cannot go anywhere else. |
This is true if both legs were in phase, but because they are out of phase, then the centre of the transformer primary winding has zero signal, because the signals cancel. Common mode rejection relies on this situation. If you did have a floating centre tap on the primary, and you looked at it with a scope, there would be no signal (assuming perfect balance).