What Sensitivity with Tube Components?

I would not try to cure the brightness by going to a tube amp.  Somewhat counter-intuitively, it would stand a very good chance of worsening the brightness.  The reason is that relatively small speakers such as yours, that strive for good bass extension relative to their size, are often designed with a lower impedance in the bass region than at higher frequencies.  The idea being to capitalize on the fact that a solid state amp will deliver proportionately more power into low impedances than into higher impedances (assuming the amp is operated within its capabilities), thereby enhancing the speaker’s deep bass response.  A tube amp will not perform in that manner, and depending on a number of variables specific to the particular tube amp and speakers, and also on which output tap is used, will very often deliver even less power into a lower impedance than into a higher impedance, resulting in an overly bright sound with a speaker designed in that manner.

I couldn’t find an impedance vs. frequency curve for your particular speakers, but that is one of the reasons that many B&W speakers are not considered to be tube friendly.

Good luck.  Regards,
-- Al

It is unfortunate that today you can spend $2,000.00 on speakers and not be satisfied.

Sure, in the total these are inexpensive speakers and maybe I expect too much?

wcc010 - imo - Those are not inexpensive speakers. And they definitely will not replace what a 12" woofer will do.

I am curious to know what happened when you switched to the low impedance speaker setting on your amp ?  Did it change anything? 

Cheers

There are plenty of speakers in that price range that are outstanding. You should take a gander at Harbeth,Spendor,etc. I think a sealed two way monitor will give you a satisfying musical experience!

ct0517, yes when I did switch the impedance and switch there was a definitive change, and not for the better. Mid-range was more pronounced but almost to the point of distortion. (only way I can describe it) Otherwise I didn't notice much too much change. I didn't leave it there for too long as I was not happy with the change.
Currently I am using 12 ga cables with bi-wire at the speaker end only. Perhaps I will try a true bi-wire set up with the switch set to low. Worth a try.
I listened to these speakers at my local Mcintosh dealer, B&Ws & Mcintosh 275 amp. I was very disappointed with the sound, actually the Yamaha was more to my liking. So to say that B&W speakers may not be "Tube Friendly" sounds quite plausible.

I think almarg is giving you some good advice. I have been using low-medium powered tube amps for 40 years, and if you want to get into tube amps, I would not say anything to discourage it, they can provide a very satisfying listening experience. My advice is not to get too hung up on speaker sensitivity. The key is to mate them with speakers that have a fairly benign impedance in the 6-10 ohm category. For instance, the original Pro Ac Reponse 2 had a sensitivity of only about 85 db, but they worked nicely with a 50-watt Audio Research tube amp that I had at the time, because the Pro Ac impedance was perfect for the amplifier. On the other hand, there are speakers out there rated at 91 db sensitivity, but the impedance is 4 ohms or less and would not mate well with most tube amps. I'm not sure about the impedance rating of your current speakers, but that would be the place to start.