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.  

I would say, start with an Anthem MRX 720 or similar. If it needs more juice, you can always add any number of amp channels.
Interesting!  I'll check it out. I was interested in the HEOS that Marantz and Denon include, but DTS PlayFi looks similar.  The only other thing I see missing is the 8K passthrough support for future-proofing and analog video inputs for a VCR -- I use the AV8801 to convert analog video to HDMI for capture and it's really pretty good at that.  Apparently the Denon and Marantz products above can do that as well.
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.

I went from an Anthem D2v to the AV8805 and find it much easier to navigate as well in 2 Channel much less sterile than the anthem. I am only using it for 5.1 but maybe sometime I may try Atmos but not in the budget anytime soon.
Look at the Integra DRX Line.  I went from the Marantz to Integra.  PLenty of power and all in one unit.
I will keep using the Parasound A21+ for the 801s -- it's a fantastic combination that sounds great, whether it's playing softly or rattling the dishes  The Parasound made an amazing difference over my 30 year old Nakamichi PA7 amp, keeping everything in the music mix crystal-clear even at high volumes without any congestion.  My lovely wife no longer complains when it's up loud.  But this is something I don't want to lose by going to a lesser preamp in the preprocessor. 

This mix is 80/20 movies/music with music streamed mostly from AmazonHD or my ripped CD collection from FLAC.  I don't play records very often (mine are all very old and scratchy), but still need a phono section.  But music is on quite a bit while I'm doing other things in the house, and Alexa/HEOS with AmazonHD music would be a welcome improvement, especially if everything can be turned on with a voice command rather than using 3 remotes (the Nak has no 12V trigger). I know both Marantz and Denon do this well.  And I've seen comments online that the analog section in these AVRs is really pretty good. 

So, after a whole lot of forum perusing, I'm now tilting towards the Denon AVR-X6700H (140wpc x 11) -- the price is right and it wold be great if I could use it to biamp the HTM71S2 center (not clear if that's possible but not a deal-killer as the center is not really used for music).  That leaves 9 channels for the surrounds -- 2 sides, 2 rears, plus maybe 4 smaller speakers in the ceiling for Atmos, none of which should tax 140wpc (I know it's less if all channels are driven). There is also the higher-end X8500H or the ridiculously priced A110 but those are both 2017 or maybe 2018 designs (8K support was added to the A110 and). I think I've learned that lesson -- get the latest prepro possible and only expect it to last 6 years. Bummer, but it is what it is. 

And I've seen comments online that the analog section in these AVRs is really pretty good.
Well, pretty sure you didn’t read those comments here.  IMO you have a good amp and speakers, and it’d be a shame to hobble them for 2-channel listening with the crappy preamp section of an AVR (unless you really don’t listen critically).  I think taking advantage of an AVR for the processing and amps for the other channels makes a lot of sense, but I’d recommend investing in a good stereo preamp with a HT bypass to handle stereo listening as it’ll greatly your improve performance there.  Preamps matter — A LOT!  Just my $0.02, and best of luck. 

It doesn’t appear as though the OP gave Anthem much consideration.  The Room Correction is definitely a plus, particularly 2 channel listening.  Why would you go back to Marantz after the bad experience you had?  Even if their products were more reliable Anthem is superior quality.  I haven’t bought any Denon gear for a while but since they merged with Marantz I have heard that it’s the same stuff, different logo
I've been using the Marantz 8801 as a preamp and enjoyed listening to it with two channel music or 3 channel video for movies. While a dedicated pre-amp might get me a little closer to nirvana, since I don't have a dedicated listening room (the kitchen is nearby) and we spend much more time watching movies and TV than critically listening to music, squeezing the last ounce out of 2-channel listening probably wouldn't be cost-effective. That said, I still have the Nakamichi CA-7A preamp from the 80s, so it'll be fun to swap that in to see how it sounds.  Given the age and the fact that it's never been serviced, I'll have to see.

I've seen comments that the preamp section in the top-of-the-line or near-top Denons outperform my 6-year old 8801 although the lesser power supplies cause me to question that. Still, I do like the way the 8801 sounds on 2-channel music so I hope that's true. I also believe the top-of-the-line units can disconnect the amps and only function as a pre-amp.
Regarding Anthem, teh room correction does look terrific, especially since I wouldn't have to run a super-long mic cable to my equipment cabinet.  However, my dealer doesn't carry it and other than custom install shops, there are no dealers nearby (according to the website).  It also looks like they're in the midst of a changeover to new products, releasing this month which have a lot of "coming soon" and no longer list PlayFI. HEOS is something that really interests me for playing lossless music like Amazon Music HD over the interwebs.  Integra has PlayFi, so that might be worth a look -- just haven't heard much about that brand.

Anthem also doesn't have an analog component video input (yes, I still have a VCR and have recently been using the Marantz to convert, upscale, de-interlace and capture family video using a cheap HDMI capture device -- still a work in progress).

Anyway, thanks...
we spend much more time watching movies and TV than critically listening to music
Under these circumstances I’d just get a good AVR and call it a day.  I don’t think it’s worth the added hassle/expense of buying a prepro and separate amplification.  If you’d appreciate a little more transparency, detail, and reliability I’d go with a Yamaha RX-A2080 or 3080, but if you like the warmer, fuller Marantz sound just stick with one of their AVRs.  And you should definitely try the Nak preamp — could be very interesting. 

I had an 8801 with marantz multi channel amp. then traded up to 8802 so I could use Atmos. I finally sold that and upgraded to a Trinnov Altitude which of course is much more expensive. Although the Marantz never gave me any problem and sounded fine, I’m through with Marantz (or any other manufacturer that doesn’t upgrade their products and make you buy new units when upgrades are available.) The trinnov allows for upgrades so that is why I went that direction as well as much superior Sonics. I also traded my Marantz amp for an ATI 8 channel which is better as well.
+1 soix

If movies are the main consideration, I would also save money and just get an AVR, one that has the features that you require, such as being able to hand the VCR and the Edison Cylinders and whatever else you might have in your Aladin's Cave