Rectified Voltage doesn't seem possible
The voltages shown are measured relative to ground, and they are assuming an AC-coupled average-reading multimeter. It's a simple bridge rectifier. The 10nF capacitors are to reduce buzz in the audio from the diodes.
The AC voltage coming out of the transformer secondary (red-to-red wires) will be more like 240VAC RMS. Half appears at each side relative to ground (when your multimeter subtracts the DC component as they normally do).
Peak voltage from a bridge rectifier, of course, is \$\sqrt{2}\$ times the RMS voltage, and the filter capacitors mean that you will measure close to that (minus a bit due to the ripple under load and the diode drops).
Here is a simulation showing the two voltages AC1/AC2 relative to ground and the transformer output voltage (AC1-AC2) and the DC output voltage (relative to ground).

If you imagine an average line for AC1/AC2 in the middle between the two peaks and ignore that DC offset (as your meter will on an AC volts range unless it is not an ordinary multimeter) you can see that the total amplitude of each relative to ground is half of the transformer winding output voltage.