can i use this one amp for my power to the 950?

Brief answer: Probably not.

Long answer: We are talking about the HK PA2000, right? It's the only "2000" amp from HK that I can find, but it is a stereo amp rated as either a 2x100W or a 4x45W amp. When not "bridged" it offers output for four speakers, but it has to be two pairs getting the same signal from the lone stereo input, so we're firmly stuck in the realm of stereo only. The real question here is how many speakers you plan to have. If you are only driving two speakers (doubtful, but always possible), then the PA2000 would be just fine. For anything more than two speakers, you could still use the PA2000 but you'll need at least one more amp to drive the additional speakers.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

would one m200 and the hk be enough to power two fronts center and rear speakers?

Nope, still a little short on channels, I'm afraid. For two fronts, a center, and two surrounds, you'll need five separate amp channels. The PA2000 only has two channels, although the "4x45W" bit can be a bit distracting (it confused me for a while -- what they mean is that they can drive two pairs of speakers, but both pairs will be playing back the same stereo input, sort of like the "A/B/A+B" option for the left and right speakers on some receivers). The Model 200 is a monoblock that can drive one speaker. The HK PA2000 and three Model 200's could power the mains, center, and surrounds. In that case, I'd use the 200's for the mains and center and the PA2000 for the surrounds.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review