Whether you're listening at ten watts or a hundred, the most dynamic range occurs within the first watt of playback. This equates to around 30 dB of dynamic range in that initial watt. Adding a second watt increases the range by another 3 dB, and from there, the power must double for each additional 3 dB increase. In audio, power yields diminishing returns.

In a typical small apartment, the noise floor during the day is around 45 dB. The softest tone the human ear can detect at 1,000 Hz is about 5 dB. For a tone at 30 Hz to be just audible, it must be at least 60 dB.

In a 600,000-cubic-foot concert hall, a full symphony orchestra can reach a sound pressure level (SPL) of 120 dB at the listener's ear. The power required to achieve this level is immense. However, if you transpose this to a 4,800-cubic-foot listening room, the power needed to reach the same SPL would be much less. Assuming the listener is seated about 8 feet from the speakers, reaching an SPL of 120 dB would require approximately 40 acoustical watts. Some modern speakers have efficiencies as low as 0.1 percent, while the most efficient ones approach 40 percent. A 0.1 percent efficient speaker would require 400 times more power than a 40 percent efficient one. In fact, to achieve 120 dB at 8 feet, the 0.1 percent speaker would need 40,000 watts, whereas the 40 percent efficient speaker would only need 100 watts.

You might think there's a significant difference between a 2-watt Zen triode amplifier and a 120-watt solid-state amplifier, but in reality, it's only a 20 dB difference. On a 100 dB efficient speaker, 2 watts produce 103 dB, while 128 watts from the bigger amp produce 121 dB. If you set the volume for a peak level of 100 dB (which is much louder than the average home listening level), there’s no difference between the 2-watt amp and the 120-watt, 250-watt, or even 40,000-watt amps. If you want that extra 20 dB of dynamic range, lower the noise floor and listen at night. This will sound far superior to the same dynamic window during the day, even with a larger amp, because there's 20 dB less ambient noise polluting what you hear.

For what it's worth.