Processor question

I have not heard either, but I have done a lot of reading on them.  Based on what I've gathered, I think the Maestro X9 might be suited a little bit better for HT/movies.  The consensus is that it sounds very good, but the flexiblity on configuration is not the best.  For example, you can only set on bass cutoff frequency for all "SMALL" speakers instead of assigned a different cutoff for each set such as left/right, center, surround.  If this doesn't bother you, I might tilt a little more towards the Maestro.

The McIntosh looks awsome, but I think it might be a just a little bit warmer sounding and more forgiving of bad electronics / source content.  I can't say for sure, but that's what I gleam.  The McIntosh might be just a bit better for music, depending on what your tastes are in type of sound.

@moag - yes, it is unfortunate that this is the case.  millercarbon pretty much just copies and pastes the same dang paragraph on every new HT thread topic.  Others also have the same kind of opinions.  Some of these comments do have an element of truth - a dedicated high end 2-channel system can generally indeed have a better result than a multi-channel home theater.  However, that's not the same thing as saying that a multi-chanell HT system will never sound good for music.  I own and also have heard some pretty damn amazing HT systems for music (but also have heard crap).  It all depends on what equipment you buy and attention to things such as power cords / fuses. 

I don't think the MX123 or Maestro would be bad choices at all.  I think they might have a slightly different sonic signature.  The Maestro comes in at 29 lbs, so it's definitely not a light weight device (indicates a good linear power supply and transformer, etc.).  the MX123 is 9 lbs heavier, but you also have that heavy glass front as part of the weight.  That being said, McIntosh MX123 also has excellent power supplies.

If I remember correctly, the MX123 uses the Marantz digital/DSP processing section, but uses McIntosh power supplies and analog output stages.  There's nothing bad about the Marantz digital/DSP section.  Generally, that's not the most important part.

I don't know what your budget is.  If you are looking at purchasing these two options as "new", another option to look at is to find a good used MX160.  The MX160 uses the Lyngdorf digital/DSP section instead and has better results and better configurability.  I think the power supplies and analog stages are also better than MX123.  HT Processors tend to drop in value really fast, so you should be able to find a used MX160 in the $8-10k area (there's one on audiogon now for $9995).  They won't be more than a few years old.

@dbphd - have you ever tried using your SP3 as the preamp?  I would say that the analog input/output sections on the SP3 are at the same level as a high end 2-channel preamp.  I would give it a try.  At that point, the KX-5 would only be used if you prefer the "sound" of the KX-5.

I run the front channel pre out from my AVR to the RCA jacks on the power amp, and I run balanced from my stereo preamp to the amp. When the stereo is active, the HT system is off, which results in no adverse affects to the 2 channel system. When the HT system is active, the 2 channel preamp is off.

I would be extremely careful if you do this.  If the amp has switch that allow you to select between RCA and XLR inputs, then great!

If the amp does not have a switch, it is likely that the RCA input is wired directly to the XLR "positive polarity" pin.  You could potentially cause damage on the unused preamp because the voltage is feeding back into the analog output stage of the preamp/processor that is turned off.