More power for better sound at low volumes?

Based on my reading, there's an additional factor that might be of importance. That would be the ratio of power supply wattage to output wattage. I'm not a designer, but one told me long ago one of their general rules is that for a 40+40 RMS output amp the typical designer would spec a power supply at about 240 watts, give or take. Many great sounding amplifiers up that ratio greatly. Accuphase, as an example, I believe runs their amps at about a 10:1 ratio, which has the additional benefit of doubling wattage into declining impedance, all the way to 1 watt. Just another thing to consider.

Gonzalo, I disagree with your answer to the question that wasn't asked.

My vote is for low noise (battery power is amazing) and hi efficiency speakers.

For starters, there’s a lot of good information in the answers above. Try some of them to determine what works in your environment (room, amp, speakers, etc.).

I listen to my system primarily at night when other family members are sleeping. I once fought the frustrations of low-level listening and tried many things to improve the sound: different amps, sources, speakers, subs, etc. Not necessarily in this order, here are the three solutions that worked for me.

1. Modern Speakers. I admire older/vintage speakers and have owned dozens. Many have beautiful wood cabinets and attractive/interesting designs. Not all new speakers are better, of course, but a few stand out. For me and my room, the best options were speakers from Paradigm and B&W. Both brands have a wide selection of value/quality speakers and many price points. The two finalists were the B&W CM5 and the Paradigm Reference Series 20 v.5. After several auditions the Paradigms 20's won. I don’t use a sub because the Paradigms meet the needs of my room and ears.

2. Quality, Modern Source. The sky is the limit if you want to spend money but don’t be fooled by reviews and prices. After spending a lot of time and money auditioning different sources, the Oppo BDP-95 was the clear winner. It has excellent sound quality as well as an eclectic mix of inputs, outputs, and features to meet my needs.

3. Amplifier Technique (pre/power): My real answer to the original question: How to achieve good low-level sound quality. I think the key is to boost/EQ frequencies that don’t respond well at low volumes. I hope I haven’t bored people with the Speaker/Source comments. I think it’s important to think of audio playback as a system and there are many important parts. Amplifier configuration is the key to low-level listening in my room. I have an integrated amplifier with two key features: bass/treble controls and a tone/bypass switch. The bass/treble controls are both positioned at 3 o’clock which is somewhat aggressive. For low-level listening, I use the tone/bypass switch to engage the bass and treble settings. This brings both low and high frequencies into better level alignment with mid frequencies creating a near-flat response. Adjust for your room and volume level as needed. When listening at medium/high levels, I engage the tone/bypass switch to remove the bass/treble controls from the circuit. At medium/high levels, my speakers are better able to respond and the sound is excellent without bass/treble alteration. Also, I can control the tone/bypass switch with a remote which makes this technique very convenient. The same technique can be used in any system with bass/treble controls. The level of manual effort varies slightly if your system doesn't have the remote capability.

I have built and modified many amps and pre amps and the biggest difference is in the power supply. This doesn't mean buy a power conditioner which will help if you actually have currupted power in your location but that will not correct a cheaply made power supply. This does make the most difference at low volummes because you are not far from the noise floor. Better capacitors,bypassing, and high speed soft stop or hexfred diodes make a huge difference and again because of lower levels the most bang for the buck is in the pre amp. Forget more power, maybe better lower power never forgetting the pre amp is first.