Replacement for Marantz AV8801: another prepro or receiver?


My 2014-vintage Marantz AV8801 prepro lost its HDMI audio -- was able to get it back (posted that elsewhere) but likely temporarily. 

Given that I'm planning an Atmos surround system, it's time for an upgrade, which is a shame because it's a great unit, but barely going for anything online and I wouldn't be comfortable in selling it or even donating it to Goodwill. So while it works, I'll try to figure out what to replace it with.

I currently only have a 3.0 system: I currently use the AV8801 to drive two B&W Nautilus 801s for the fronts via a recently acquired Parasound A21+ and a B&W HTM71S2 center with an old Nakamichi PA-7. Since I'm going to Atmos, the conundrum is whether to get another preprocessor: most likely an AV7706, which I'm assured has better processing and sound than the 8801; the 8805 doesn't support the latest standards without an upgrade that is not available and there's no 8806 on the horizon.

The alternative is a receiver like the Marantz SR8015 or Denon AVR-X6700H. All three came out within the last 6 months so they should support the latest standards.  I like the idea of 11 channels of amplification to deploy as I see fit.  If I go that way, I'd like to biamp the HTM71S2 center with two of the channels and use the rest for surrounds (exact configuration still to be determined). 

What I'm wondering is whether the amplification in these receivers is good enough for the surrounds, or whether I should just get the preprocessor and some configurable amplification like Emotiva with a high-power module for the center and lower-power modules for the ceilings and surrounds.  

Opinions?
128x128invaderzim
I agree AVSForum will provide you with access to a lot more information and expertise, but I'll chime in with saying I recommend the Denon receivers or Marantz processors, unless you are going to look at something higher end in which case I'd recommend Trinnov.

Whether or not the Denon receiver would have enough power for your speakers would depend on their distance from your listening position and the volume you watch content at. Personally I have not gone back to a receiver since moving to a separate processor and amplifiers.
Thanks!  I'm leaning towards the Marantz AV7706 processor and deal with the amplification later. I'll post in AVSForum.
AVS forum has a strong bias towards all receivers sounding the same, all amps sounding the same, cables are snake oil and so on.  Unless they've changed their ways, it's best to know the bias going in.

It sounds like the OP has been running a 3 channel set up only with the Marantz prepro and is looking to upgrade to Atmos, with all of the extra channels that this requires.  Also, it looks like the B&W fronts he has go down to 3 ohms, and their spec is that they'll take up to 1000 wpc.

That being the case, I really think that no receiver would do them justice.  I'd concur that the Marantz 7706 would be the best option.  The tricky part is getting the exact same amplification across the front 3 channels since the Parasound A21+ would then be on the left and right.  Parasound doesn't make a monoblock that would match the A21+ for a center channel, so a new multi channel amp might have to be acquired.  The A31 might be close enough, but in needing 9 or more channels at 250 wpc, that's going to be a chunk of change on top of the speakers needed.