Multichannel amp s for an all B&W system?


I have an EAD Theatermaster Ovation Plus and B&W Matrix speakers (801 Series 3 mains, HTM1 center, SCM-8 surrounds).

I'm currently of the opinion that my Krell KAV-500i amp is the weak link in my system, so I'd like to upgrade. There's a slightly dark, mechanical, airless quality to the sound that I'd really like to get rid of. I suspect it's the Krell because that's exactly the sound I heard from the Krell Home Theater Standard pre/pro when I demoed it against the EAD Theatermaster.

The Krell amp is 100wpc and has great bass control. I'm seriously considering the EAD Powermaster amp, but I'm not sure if I should go with the 200wpc PM1000 or the 400wpc PM2000. Would the PM1000 risk sounding wimpier than the Krell?

What other amps I should consider? I'm looking for ones that err on the side of liquid, airy, and unfatiguing, but not at the expense of bass control or detail (isn't everyone?).

Thanks,
chouca
The two 5-channel amps that I'd audition if I were in the market are the Theta Dreadnaught (the original Dreadnaught is a great used buy) and the Bryston 9B-SST. If you use your system mainly for music, you might also consider getting a 2-channel amp for the main speakers and a 3-channel amp for the center and surround speakers (or a 3-channel amp for the left, center, and right speakers, and a 2-channel amp for the surround speakers).
I use to have the Powermaster 2000 with 400watts and it is an excellent amplifier and extremely musical with my EAD Signature.. I only sold it to buy Lamm's for my 2 channel system.. the Sunfire I bought to replace is not in the same league as the EAD but is cheap...
Thanks for the suggestions, you've given me some new options to consider. The Classe and Theta seem especially worth evaluating against the PM2000.
if you have the krell kav-500i integrated amp it is 250 per channel not 100 unless you have 16 ohm speakers. the krell should not be a weal link in your system the reviews i have read say it is reasonably strong. in any event if you do not like the krell how much do you want for it and i would say you should get a couple of bryston 7b-st monoblocks and your problems will disolve into nothing and you will not even remenber you had a issue
You may also want to consider the Cary cinema series amps. While the Cinema 7B I use is only 100 per channel, it has plenty of grunt to power my B&W system (802D, CMC CM7). It is very musical so a 2 channel won't be needed. The more powerful Cinema 5 is 200w X 5 and generates great reviews. It compares well the my Krell 400xi- not quite as deep on the base but well controlled and certainly not lacking. If this gives you any idea, I havent used the Krell in a couple of months and havent missed it.