I like the idea and it's what I do, an AVR with the latest everything in technology that has pre-outs and an external amp. That's what I do and it works quite well. Denon X3400H with a Parasound HCA-1205A 5 channel amp. All the tech, Audyssey XT32 and plenty of power from the Parasound amp.
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Just fyi, I tested the AVR-X3400H for about 10 days in 2017 but only in 2 ch stereo and listening only other than plotting a few graphs with REW. During that time, I was shocked it sounded no different than my Cambridge audio preamp and Parasound Halo A21 combination, even just sighted test. I sat about 10 feet from the big R900s, with volume no higher than -20 so the >60 lbs with 2.5X the output had no advantage.
DBT is important for those who wants to argue, but I have been around too long to be fooled by just the look, weight, price, and all those subjective reviews that flooded audio forums.
So I hope you will keep it for something else if and when you upgrade to something better. And by the way, it was much later than I found out the X3400H's preamp/DAC section looks identical to the X4400H, 6400, and Marantz SR6012, 7012 (except the HDAMs). That thing has the same design, parts and circuitry as the higher models except with less channels. Had Gene reviewed and measured it on his bench, I bet he might have it on the 2017's best product list.
