Another wattage question.

That is fine as long as you are reasonable with the volume.

Jzzmn88,

Kchahoc's answer is correct but that is one aspect.

Another aspect is how much power do you really need for the N805S??
The tech. spec says 88dB @ 1W measured 1m away.
So, if you are sitting 2m (6.6ft away), the SPL at your ears is really 82dB using 1Watt.
So, you'll get 92dB SPL @ 2m with 10W.
you'll get 102dB SPL @ 2m with 100W.
you'll get 103.6dB SPL @ 2m with 120W.
Given that we all have atleast 2 speakers in the room working at the same time, actual SPL = 106.6dB @ 2m @ 120W.

By this time the little midrange driver would have compressed!
So, really, you are just fine with a 100W amp.
But......but.....what is *more* important is what is the *current* delivery of this 100W amp???
If it is poor/mediocre, the N805S will not shine as a speaker in your room.
What is really needed is a 100W (or a 120W) amp with very high current delivery. That's what you are missing!
I was a B&W owner at one, so I know this issue with their speakers.
If you get one of those Parasound that have modest wattage but very high current delivery, you'll solve your problem w/o needing to get a higher wattage amp. You still could but it isn't necessary - you need gobs of current.
FWIW. IMHO.

As per Bombay, above. Note, however, that you need the "energy" producing capabilities in an amp in order to enjoy the dynamic headroom in music. In Bombaywalla's example above, the amp will be able to give you ~20db of headroom (difference b/ween the lowest amplitude and the highest, in the same piece of music, without changing the volume) without clipping. Say, when a full orchestra suddenly enters the scene after a quiet cadenza...

bombaywalla: another newbie here... thanks for the tech info. I always wondered how that worked, spec wise. I do have a question, however, about "current" delivery. If VxA=Watts how can high current delivery(amps I presume) still give modest watts? Doesn't VxA=W always hold true? The voltage is fixed yes/no? so increasing the amps will always increase the watts. Be gentle to me :0)

A common rule of thumb is selecting an amplifier is that the power rating should be 50% to 100% greater that the maximum power handling of the speaker if you are concerned about thermal overload (blowing out the speaker). The power rating of an amplifier is based on a connected load, usually 8-ohms. It is also based on a nice, clean sine wave signal. The music signal is not a sine wave but of one with dymanics (as Gregm notes above). This will cause more of a load on an amp to get the music signal as loud as the reference sine wave signal. That the reason for the higher amp power selection.

The low side of the recommended speaker power is to prevent the amp from clipping if you attempt to play at higher volumes. Clipping can damage a speaker driver just as easily as an overload - especially with digital sources which have very high dymanic swings.

So, you will be okay with 200 to 240 watts. But as Kchahoc states above, if you are reasonable with the volume control, going above 240 wpc will not be a problem. The best thing to do is to contact B&W as ask if the make and model amp has any problem they can foresee.