Some additional considerations are:
My AV control equipment is on a series of cabinet shelves that are difficult to reach around. The shelf that holds the preamp is ~9.5 inches high, so height needs to be less than 9.5". Significantly less than this maximum would also make cable changes easier and may help with air flow, if vents are on top.
I may be running with center channel removed from configuration at times, so performance in the non-standard mode of left/right front + surround (center channel passed to front left/right) is a factor .
I will almost entirely be watching movies/TV, rather than listening to music. I currently don't have support for 4k viewing in other devices, but expect to upgrade to 4k within the lifetime of the preamp..
I am replacing my old Lexington MC-12 preamp from 10+ years ago because it doesn't power on. I believe the power supply was damaged. This is a relatively common problem on old MC-12. However, a risk exists that something in my setup generated a surge or bad power input. If so, a similar bad power input issue could occur on the new preamp. I am using a Monster powerbar, which should have surge protection.
I have been running a Marantz, 7705 for nearly 8 months now. This is my third generation of Marantz pre/pros in about 12 years. I have in general been happy with all of them. Although the ergonomics of the first was not intelligent to say the least.
I have kept with Marantz, if for no other reason that I'm used to them. My system requires balanced and unbalanced outputs. That is an absolute requirement. Also I like the bass management. All speakers except the four ceiling speakers are run large. The mains are truly full range speakers with prodigious output to 20 Hz and below, but the LFE is captured and mixed in. All speakers have good output into the last octave. All are TLs except the surrounds and ceiling. So the front three and the rear backs are TLs, and the surrounds and ceiling are sealed. So all speakers have second order roll off. That helps really smooth the bass response through out the room. So all except the ceiling speakers are run LFE + main. They are all robust enough to tolerate this, and I'm yet to bottom a driver, even in the loudest of explosions.
So I have found the fidelity excellent and the ergonomics satisfactory. I only use Audyssey for level and distance. The measured in room response is such that Audyssey could not improve it only muck it up.
The S/N is only just adequate. I'm running 11 channels and each adds noise. The 100 db weighted is cutting it fine and running close to the wind.
I have 18 power amp channels. When the amps are on, the room is totally silent. When you switch on the 7705, if you listen hard you can just hear a faint hiss. I admit you never hear it on program, but they should do better.
I have had a couple of problems. Those very nasty plastic test mics that come with them did not work on this one. It was DOA. So far Marantz have been unable to replace it. They just don't seem to have any. However since I use them just for level and distance and not Eq, I can use one of the others I have. I'm pretty sure they are actually the same awful mics no matter what Marantz say. Devices as horrid and crude as those are totally unsuited to perform any critical measurements what so ever. Anyone who thinks they are naive in the extreme.
There has been one other problem. Probably 3 or 4 times in the 8 months I have had it, it makes a loud bang though the speakers and then they all hiss loudly. If you switch it off and then back on it performs as it should. This occurs probably 30 seconds or so after first turn on of the day. So I have taken to turning it on a significant time before turning on the electronic crossovers and power amps. It has never done this during program. I think it would be useless to send it in for service, as you could be certain it would never do it on the test bench.
So with those caveats it has been a good unit and controlled the rig well in the main.
One last point. Shelves are NO good for complex systems. That just is courting trouble. You absolutely have to be able to get behind them. Without that, it is just a rotten installation. They need a dedicated mechanical chase.
