Hi faust, best of luck to you. To avoid typing a lot more information, just sharing one more personal experience to help you on your quest with B&W,
1) Go find 蔡琴's 1bit /2.8224MHz 精選 in DSD/DSF and listen to the superbly remastered '恰似你的溫柔' and '被遺忘的時光' on the B&W 800 series. In particular '恰似你的溫柔' has very sharp guitar strings (too sharp in this recording in my opinion, Eagle's Hotel California from their Live concert (Japan version) has far better guitar recording) that really test your gear pairing. Keep in mind that, living up to reputation, B&W 800 series will quickly make your previously 'ok' music records sound 'bad'. Be sure you always find the best music recordings when you evaluate these speakers. If you like classical music, try demo with 大植英次 and Minnesota Orchestra that was awarded best recording by Reference Recording.
2) Make sure the B&W is powered by reputable gear like Mcintosh (avoid tube amp or other fancy homemade stuff used by self proclaimed audiophiles until you learn familiarity). The amp you use 'must' double down in power (ex:100watt @8ohm, 200watt @4ohm, 400watt@2ohm), your Accuphase Class A is actually perfect on paper for B&W 800series.
3) Use a good modern 32bit DAC/player that properly handles DSD CDs.
4) Use quality cable at least 12AWG.
5) ***Most important of all, make sure the speakers are broken in. B&Ws take at least 200-400hrs to start to break in. Even used speakers that hadn't been played for a while also require some break in period. B&W factory officially recommends this. My first pair of 805N (18yrs old speakers), took me nearly three weeks. So many hi-fi amateurs evaluate B&W 800 series out of the box and without proper gear pairing out there it's sad how these uninformed people tarnish B&W's quality reputation.
Enjoy!
-sorry guess I did end up typing a lot anyway