Just about any mainstream preamp today will put out something in the neighborhood of 7 volts AC maximum. This has nothing at all to do with the "range" of the volume control. This is far away more than enough to drive any home theater amplifier deep into clipping. Most home theater power amps have a target gain of 28db, and require anywhere between 1 and 2 volts to drive them to full power.

Most preamps have a gain roughly in the neighborhood of 20dB, so using this figure, if you have an input voltage of 200 millivolts (far less than most signal sources can supply - most CD players supply 2 volts), then the preamp should have the capability to drive this to 2 volts - enough to drive any amplifier into clipping. Taking the typical output of a CD player of 2 volts, then the preamp would try to amplify this to 20 volts - impossible to do. So in this case the preamp will be deep into clipping - however before this, the power amplifier will be deep into clipping.

By the way, most power amplifiers are around 60% efficient. Using a power consumption meter, you can figure the rough amount of power being made by the amp. Power amplifiers don't "waste" nearly as much energy as your car!