This is a topic I've always found interesting. Like many, I feel that there's just too much gain baked in to today's systems. But, also like many, I'm not sure I always follow the math of how gain works.
Using my own system for reference (because I have the values at hand):
My amp (ATI 542NC, 500wpc NCore Class D) claims an input sensitivity for full output of 2V, with a voltage gain of 28dB.
Preamp (W4S STP-SE Stage 2) has max gain of 6dB and max voltage output of 9V, but operates as a passive preamp in the lower 2/3 of the volume range, below setting "63"; "64" and above is active.
DAC (PS Audio Directstream Jr) has max output voltage of 2.85V at 1khz as measured by Stereophile (ok, that was the big DS, not the Junior, but I bet they're close).
So if I run the DAC at 100% volume (typical for many, I think, though I rarely do...), and the pre at setting 62 (i.e. unity gain), my amp will be seeing 2.85V, which is beyond the voltage needed for its rated 500W. The only unknown here is what the signal level of the source file is that's driving the DAC (typically my Aurender N100H). Does this appear reasonable from a math standpoint?
And more to the point, is it reasonable that I can get enough signal to get rated power out of my amp without any preamp gain at all? That seems wrong to me - what's even the point of preamp gain then?
One more question that's operationally related instead of theoretical: I typically listen at what are probably considered moderate to lower volumes. Fortunately, my Focals have proven to be fairly adept at being dynamic and involving when not being pushed to ear bleeding levels. But does it matter how I set the gain on my components? If I leave the DAC at 100%, the preamp is at ~15 for a comfortable level (remember, unity is 63, max active is something like 84). Would it be better to dial back the gain on the DAC to ~75%, which allows the preamp to run at setting ~30? Or even more attenuation on the DAC to bring the pre into unity or slightly active gain?
