Summary:
I bought a second-hand pair of those monoblock full class A amps to drive the B&W801F in a medium / large sized listening room of 6*4.5*5.5 mt.Those loudspeakers are very low efficiency (82 dB 1w/1m) and current consuming
(impedance is 6 ohms @100Hz, 48 ohms $2KHz) and a powerful / stable / high
current amplifier is required.
The A100Ms do an excellent job here, and there is no match with the Quad 405.2
(rated 100+100W as well) I used up to now.
Compared to the Krell KSA100S, I cannot hear any major difference. The advantage
using Krell is that heat dissipation is lower (this is most likely due to the
full plateau biasing).
I would then rate 5 stars.