High power amp, does it matter at low volumes?

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.

@OP I'm sorry to say it, but B&W 800 series speakers are probably the worst choice for listening at low levels. They will sound better with a better quality amplifier but I think they will still sound dynamically flat at low levels regardless of what you feed them with.

Hi yoyayaya,  Yes, these speakers definitely have a "wake up" amp level.  Below 21 or 22 on my preamp control, pretty dull. Above that level, like 23, a whole new sound. What you learn as you go.  I am not planning on trading in speakers, but, some day I may go that route.  

 The power amplifier has a specific job to do, as it is an electronic device designed to increase the power of an input signal (source), and in this case, to power speakers. Before getting into the amp/speaker relationship, it has been my experience, that the gain and impedance between the source and the amp, has been critical for the amp to do its job and to sound proper. When selecting speakers, the listener will determine (hopefully) that the speakers cater to his/her wants, needs and desires. Speakers need to "work" in the room, and a happy marriage of speaker/room/acoustic control, should be "set up" to properly showcase the specific attributes of the designer's quest, at the listening seat (for those who have a listening seat), as most here, do. I am stating this because this is why we spend our money. Now, what power/current necessities do these speakers require, and how loud (SPL/Dynamics) are you looking to achieve. The reality is, all amps have a sound (least colored ime, has been the Benchmark AHB2), and of course, in my system. And sensitivity wise, small amps love my Lascalas...they thrive. However, because I listen at realistic levels, my larger amps (1.5 kw transformers and tremendous capacitance), are so much better at giving me what I want, and the speakers, room and yes, my ears/brain, enjoy big power. Did someone here actually recommend a tube amp to power your B&Ws? My experience tells me, your B&Ws should work very well with your L 532. And let's not forget about "Synergy", starting with the speaker/room and continuing up the line, at the beginning. At low volume, the music lacks the excitement I require.  Headphones are great for those times, and I am blessed I share walls, with no one. My best, MrD.