Originally posted by gonk:
Active tri-amping with a 7500 will certainly give you a lot of power to work with. Without knowing what speakers are involved here, I wonder of a 7075 or 7125 would be a good fit.
The 7075 would undoubtedly be powerful enough for the tweeter and perhaps the midrange. There is very little power used in those regions. The woofer is the component which needs the power, and even then, if a subwoofer is used, even that requirement for power is lessened.
If it were me, I'd use tube amps at least for the mid and tweeter, with a solid state amp for the woofer, which needs the damping factor.