On the "alpha" version of the Audio Refinement Complete integrated amplifier, you have to hit the "AMP" button followed by the "STOP" button to activate the pre-amp outputs. A relay will click and you'll see a faint blue light under the front of the unit. Pressing the "STOP" button a second time will deactivate the pre-amp outputs. Not sure if this works on the pre-alpha version or not.
Here is the description from the manual. I quote directly, bad grammar, typos, and all.
"IR SENSOR AND PRE OUT INDICATOR: This sensor receives a signal from the remote handset, it also used for the function of indicating pre-out is enabled, as you press the "AMP" button on the remote control and then press "STOP" button, a light blue LED behind the acrylic under the panel will lit up, indicating that the per-out function is enabled. Pressing "STOP" button one more time will turn off the LED and return to the original state without pre-out."
"PRE-OUT: Pressing the remote control of "AMP" button, then press the "STOP" Button, after 3 minutes the pre out function will be enabled, the signal will through volume control and could supply to subwoofer or power amplifier."