Would like to hear more of your thoughts on the pre concerning using it as a 2 channel pre. Looking at one now and I'm leaning towards buying it.
The MM9000 is supposed to be a really good sounding amp.
Spec-wise, it's very capable for 2 channel audio. It has 4 digital inputs via 3 different digital signals, RF(mostly a Laser Disc thing), toslink, and RCA coax. The digital inputs are assignable via the buttons on the front panel or the master remote.
You will want to check that it has the remote control because it gives you faster access to the setup modes, and to create shortcuts on your system. The front panel buttons will get you into the basic modes, including a stereo mode. I set mine to 'Stereo' and 'Auto' to recognize the PCM stream from my DAC, and it worked without incident. I was curious to hear any artifacts from my 16 Bit DAC being converted to 24 Bit by the AV9000. I HAVEN'T HEARD ANY. Combined with the MM9000 amp, I had to turn off the equalizer in iTunes because of the extra detail I was hearing compared to my Yamaha 50W amp. I'm not dissing the Yamaha, it has a good sound, but clearly the Marantz has power, clarity, and punch over it (170W vs 50W). Back to the preamp.
The 'detailed' parameters are only displayed via video, so If you want to try the surround modes, you will need a monitor with at least one legacy video connector. Again, the front panel buttons can get you global setting on surround, but specific settings are remote control only.
About the remote. It is cryptic. There is an online site that will allow you to view the pages one at a time, but not download without a paid membership. Even the instructions are cryptic, sometimes I have to re-read multiple times. I'm so glad the Auto setting grabbed the stream.
About the MM9000 Amp. The 5 channel amp has individual input control for each channel, a real plus if the master remote isn't included. It's speaker-posts easily accept large wire. The knobs are color-coded red or black for the polarity of wire. The amp also has a 'trigger' input you can connect from the preamp to put both into standby together, via remote. Another function the preamp has is 'multi-room' mode. It provides a separate send from the 5 channel mode, but I haven't tried to use it yet.
At first I thought the pre / power amp sounded harsh with my Klipsch, compared to my Yamaha amp. I had my 'Aha' moment when I realized iTunes equalizer was still enabled. The Marantz gear really woke up my speakers, and I no longer needed as much EQ. Now iTunes runs essentially flat, and the sound is clean, detailed, and dynamic. I really like this upgrade. The AV9000 has some good reviews for 2 channel audio, and some not-so-good reviews about the way THX is implemented. Basically the audio side is great.