High power amp, does it matter at low volumes?

@robeffy   Absolutely!!!!  Higher damping factor/Power/current (I call it "horsepower") is critical, especially when driving less efficient speakers, and especially when listening at lower volume levels.  Higher power/current/damping factor, dredges out more detail, transparency and dynamics in the music at lower volume levels (kind of like a supercharger effect).  Happy listening. 

@roadcykler  nice!
From cables don’t matter to amplifiers don’t matter. That’s quite an evolution. Can you share what leads you to this conclusion? 

You  are correct in pushing a low wattage amp to the limit causes clipping or distortion where the top of the sign wave gets cut off on the scope. It is not high wattage that kills speakers but dirty power,then there is compression that is how speakers clear out the heat generated by the power because energy is dissaped by heat in speakers. I've always bought high wattage high amp power amps and ran them because they have alot of power for transients in music. Speakers don't always stay at the same ohms over the music frequency and some can dip to below 2 ohms. I look at my mcintosh meters and although they typically  run less that 20 watts the amps are there to push the transients.  Then there is amp a damping  in otherworldly how well they control the base. Base speakers require more amps ,wattage than mids and tweeters. Then you may change your speakers out and want a higher wattage amp in the future. Many speaker manufactures are putting class d amps built into the speakers. So much to study and learn. Enjoy the music and experience

I'm going to address this from a general perspective because very few people seem to understand the relationship between speakers that present a difficult load and the amplifier requirements to drive them.

For example, a speaker that has a variable impedance curve may present a 4 ohm load at 250 hz and an 8 ohm load at 3000 hz. I'm going to spare you a bunch of electrical equations but suffice it to say that in order to have a flat frequency response the amplifier needs to be able to double its power into 4 ohms. If the amplifier puts out 100 watts at 8 ohms and the same wattage at 4 ohms then this speaker will output less energy at 250 hz than 3000 hz. This means that these speakers will not have the frequency response for which they were designed. In this example, you will have weak bass around 250 hz where the impedance drops to 4 ohms.

So, how does this affect listening at low volumes? It makes no difference. The impedance curve remains the same regardless of volume. The same frequency response anomaly will be there at low volume as at high volume.

I couldn't find a Stereophile review of the 802 D2 but there is a review online of the 802 D. Stereophiles is the only major audio publication that tests the equipment it reviews. The 802 D presents a difficult impedance curve combined with a pretty severe phase angle which presents an even more difficult load on the amp. I suggest you read this review, and especially the measurement section, to get a better understanding of the demanding nature of this speaker.

In order for your speakers to sound their best you should use an amp that is capable of putting out high current into low impedances. Again, volume doesn't matter.

Your Levinson 532H is a very good match for these speakers. It doesn't quite double it's power into 4 ohms but it is a robust amp. You would have to spend a lot of money to get something better. Stereophile also has a review of this amp which is glowing in its praise.

I'm running a pair of Thiel CS6 speakers which are notorious for presenting a difficult load to an amplifier. However, I don't think they are much more demanding than your B&W's. The amplifer I'm running (Krell KSA 300S) was one of the amplifiers that Jim Thiel used to design and voice these speakers. My system sounds wonderful and I'm comfortable that I'm hearing the sound that Jim Thiel intended. If you decide to go with a lightweight amplifier, say with tubes, it will work, and you may even like the sound. But it will not be delivering the frequency response that B&W intended.

My advice is to sit back and enjoy the music from the truly high end system that you are blessed to have. But if you want to upgrade your amp I would recommend going with a heavy solid state beast (i.e. Krell, Pass, Levinson, Gryphon, etc.) that is rated to 2 ohms.

Pass Labs might work well.  They are known for doubling power - the "baby" XA25 is 25/50/100 into 8/4/2 - and its output transistors can handle 40 amps!

To perform well at low volumes requires low level resolution, the XA 25 certainly does that.