Mixing Tube and SolidState Amps

Has anyone heard of using a tube amp for one spectrum of sound and using a solid state amp for the other? It seems to me a friend of mine once used his McIntosh tube for the ?high end? and a tube amp of some kind for the ?lows?.

I shipped a Onkyo 8070 to a girlfriend of mine today. she has a tube amp. she also has speakers that have 4 poles on them. 2 for high, tow for low.

any help would be appreciated.
I think you are trying to come up with biamplification. In many biamp setups the tube amp drives the tweeters and the transistor amp drives the woofers.

You can try biamping any way you like but get left and right sides symmetrical and make sure all amplifiers have the same gain factor.
bingo! exactly... and there is plenty of information at hand.

thanks for your help.