How much Power do speakers really use ???????

I would beg to differ with the conclusion that Pragmatist came up with regarding the B&W's. The figures that he quotes are for a listening distance of one meter from the speakers AND do not take into account speaker compression. I don't know of a speaker made that is linear in terms of input vs output, especially when one starts hitting them with some juice. This has to do with thermal losses in the drivers and crossover components and is pretty much unavoidable to one extent or another.

As such, one should not expect to hear anywhere near the spl's quoted at their seated listening position unless one sits very near their speakers and has a very small room. To achieve the figures quoted at a typical listening distance, i would count on needing at least twice the power ( and more realistically four times that amount ) in order to keep the amp from getting nasty due to being pushed too hard. This is especially true if running a typical SS design.

My experience with speakers rated at 96 dB's and an amplifier rated at 120 wpc in a similarly sized room supports the above statements that i made. I kept popping tweeter diaphragms from driving the amp into hard clipping. Given that these speakers are four times as sensitive as the B&W's in question, i would not count on having enough muscle and doing it cleanly unless you had quite a bit of power. Sean
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So it sounds like tubes are not the best for these speakers then? Sounds like a tube preamp and something like the Bryston 14BST is the better choice? I was thinking about getting the Theta Dreadnaught II as well, but that is only 250w. I don't plan on getting rid of these speakers. In fact, I think I'd buy the 802's to replace them.

My speakers are about 7 feet apart and I'm about 8 to 9 feet back.

Ok,I see Sean's point.

Pragmatist: I hope you understand the point that i was trying to make as my post was not meant as an attack on you personally or the information that you provided. I thought that the effort that you put forth in responding was very kind and covered the basics quite well. What i was getting at is that math and various formulas can be very helpful in predicting accurate results, but only when you factor all of the variables into the equation.

Busaganashi: I think that most people would find a quality 250 wpc amp with 90 dB speakers to be plenty of power and capable of attaining SPL levels that are more than enough in the size room that you mentioned. On top of being a bit of a nut, i also tend to push things noticeably harder than most folks. As such, i try to figure for worst case scenario, which pretty has one covered under any circumstances.

If you have the opportunity to audition the amps that you were considering in the confines of your system in your listening room, i would by all means do so. Otherwise, i would be relatively confident that a well built 250 wpc SS amp was up to the task at hand for someone that was slightly more sane than myself. You might be able to get away with a slightly smaller tube amp due to the differences in sound quality that they produce under stress. Most SS amps tend to get hard and grainy if pushing them whereas many tube products remain musical, but get a little sloppier. The fact that your speakers are of reasonable impedance and not highly reactive also helps things out a bit : ) Sean
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None taken,Sean;I enjoy reading your posts,really.