The DAC is the chef. The amp are the ingredients. The speakers are your stomach.
If you use a digital volume control, you are eating it take-out style, in a styrofoam container and probably reheated with the microwave.
If you use an excellent preamp, you are eating it at the restaurant with nice clean silverware and proper lighting.
If you use a lousy preamp, then the waiter is annoying and the fork has a chunk stuck to it from a previous customer.
If you use a digital volume control, you are eating it take-out style, in a styrofoam container and probably reheated with the microwave.
If you use an excellent preamp, you are eating it at the restaurant with nice clean silverware and proper lighting.
If you use a lousy preamp, then the waiter is annoying and the fork has a chunk stuck to it from a previous customer.