I'm trying to simulate a simple full wave rectifier in LTSPICE. The output I am getting is not what I am expecting. In the picture below, the green line is the voltage output from the + terminal of the sine wave, the blue line is the - terminal of the sine wave and the red line is the output directly from the bridge rectifier (just prior to C1).
It looks to me as if there is a problem with the sine source, in that it's increasing. I've deleted the circuit several times and redrawn, and I've restarted the whole schematic file again several times. If I just place in a single sine source connected to ground and nothing, I get the expected output (cycling between +/- 34V) but as soon as I connect the - output to a circuit, it all goes crazy.
What am I doing wrong?