McIntosh MC901's internal active crossover & speaker's internal passive crossover

I own these amps, and they are all you think they would be. Extremely versatile and easy to work with. When I purchased them, I ran Infinity IRS Betas. The mid/high panels with the tube section, and the bass towers with the solid state. I did not use the internal crossover since the Betas have a servo box for the Woofers and adjustable level crossovers on the mid/high panels. These amps sounded much better than a half a dozen or more previous arrangements with the Betas.

Now they are running a set of Analysis Audio Orion Mid/High panels using the internal crossover on the amps, with no passive crossover in line to the speakers. This is the best way to run these amps and sounds incredible. Another option is to run the monos as two separate amps for two separate types of speakers if you’d like to change up your flavor. You can run a more sensitive pair of speakers off of the tube section, and drive more power-hungry speakers with the solid-state section switching between based on your mood, but this will need two outputs from your preamp.

Can’t say enough good about the MC901’s. I watch the used market daily and have yet to see a used set for sale since their introduction.

OP @ Believer

There's a lot of info here that may be relevant to your question. If you own or are looking to own these amps and are looking for info based on the specifics of these amplifiers, I can help. These are a significant investment and VERY rare in topic discussion here, so want to make sure you receive the info and perspective based on experience that will help.