Yes I am sure. In fact, Gene made it very clear too, he said:
"Here is the procedure for reassigning the front channels to the height surrounds:
- Go to AVR`s setup menu
- Select “Speakers”, enter “Amp Assign”
- Select “11.1ch” for “Assign Mode” setting
- Select “Front” for “Preout” setting. The other option is “Height”.
Connect an external
2CH amplifier to the Front L and R preouts, connect the rest of speakers (9.0) to the remaining receiver`s speaker terminals (C, SL, SR, SLB, SRB and 4 height channels) for a full 7.1.4 speaker configuration.
With the AVR-X3600H configured to reroute the main front L/R internal amplifiers, the preamp is physically disconnected from the power amp. This allows the preamp stage full capability of delivering up to 4Vrms unclipped when connected to external amplification as can be seen in the following output vs distortion plot courtesy of Sound United Engineering."
Of course Gene is correct about no other receivers at that price point has this feature, but that would be based on list prices. The nearest one would be the SR6013 and SR6014 that is listed for $1,499. The AVR-X3600H is listed $1099 and the AVR-X4500H $1,599.
Again, that's list price, street prices could be much lower obviously when on sales especially for the 2018 models such as the AVR-X4500H that you may be able to get now for $1199 or less. The Marantz had dropped to C$1199, that was about US$910 not that long ago. You won't likely see such deals for the lower models AVR-X3600H and SR6014 because they are current year/2019 models.
The only AVR that can disconnect all channels in what they call the preamp mode are the recent Denon flagship models, such as older AVR-X7200WA and the still current AVR-X8500H.
You can ask/PM
@gene if you want to hear directly from him but yes I am sure it only disconnects the front left and right channel internal amps from the front left/right preamp outputs.