Help w/ preamp

First thing, I am not a 4K expert. I only know that if you want to support 4K with all the new features, you need to go with one of the big company items (i.e. Sony, Marantz, Anthem). There are some boutique companies supporting 4K, like Krell, Theta, McIntosh, but they all have additional quirks and cost issues. (i.e. Krell Foundation has no Atmos, Theta is insanely expensive, McIntosh is buggy firmware with no support). I don’t know what to say about your issue other than it sounds like a firmware issue with regards to certain 4K standards. One thing you could try is getting a different HDMI cable. The higher bandwidth used for 4K can be a problem if the HDMI cable cannot charge/discharge fast enough for the digital square wave pulses at that speed. This could translate into communications between source/processor glitching and lost data. Maybe try a Wire World HDMI cable?

I have taken a quick look at the AVM 60. I have not heard it, but I would place it -probably- as equal to the Emotiva XMC-1. It is probably very nice sounding, but there are definitely better. Anthem is more of a boutique company and the AVM 60 comes in at $3k. Whereas Marantz company (D&M) has over 200 R&D engineers for their product development and has a huge reseller market. The Marantz is going to give you more per dollar than any boutique item. I think Anthem had a lot of success with their $9k D2 processor, so they took the software and put it in a very trimmed down platform so that they could sell it at a lower $3k price. My gut says that the 8802 (and possibly even the 7703) are going to sound better. But again, I have not listened to it.

Subjectively again, there are boutique processors that will beat the 8802a. The $9k Classe SSP-800 sounds better than the $4k Marantz 8802a, but Classe doesn’t support 4K, atmos, etc. And it’s $5k more expensive. The ~$6-7k Krell Foundation may or may not be better -- it’s controversial (some say it’s better, some say it’s not). Marantz 8802a is not as good as $12k McIntosh MX151, but it’s close.

There is a huge amount of positive reviews on AVM 60, but remember it’s all relative. For the money, the AVM 60 give you a whole heck of a lot. Many people love the Anthem room correction system. But like I said, it’s all relative and it’s a great product at the $3k level.

I auditioned the Emotiva XMC-1, which also had a huge amount of positive reviews (like stating that this thing is just awesome sounding). What I found was that the XMC was very very good for the money spent ($2k at the time), but it would not beat out my 15 year old Krell HTS, even when the XMC was playing hi-res through HDMI.  The Emotiva had a somewhat closed-in sound (common on their preamps/dacs) and did not have the "separation-of-instruments" clarity I wanted. The XMC-1 will soon be at the $3k level because of new features (HDMI2.0/4K support, Dolby Atmos, DTX:S, Dirac Live room correction).

A note on HDMI cables.  I had been using a low cost cable that was supposed to be "Premium Certified" for 4K / 18Gbs bandwidth.  It was the lower cost Belden FE HDMI cables from Blue Jean Cable.  What I found was that it was smearing the sound (audio data) from different sources.  I wasn't even using 4K bandwidth.  This smearing occurred even on just 108i with normal old compressed Dolby Digital 5.1.  As an experiment, I went back to my old Neotech NEHH-4200 HDMI cables and the sound significantly improved. 

http://audiosensibility.com/blog/products-2/digital-cables-occ-copper-and-occ-silver/#!/Neotech-NEHH-4200-HDMI-1-4-Cable/p/17895256/category=4059160

I had originally switched to the Beldon because the Neotech cables weren't even HDMI 2.0 / 4K certified, but I found that there were transmission problems with the Beldon (probably charge/discharge speed and jitter).  All my HDMI cables are 6 feet, so I don't have the "short cable reflection" problems.  Supposedly, the Wire World cables are even better for bandwidth because of their DNA Helix architecture (The Wire World Starlight 7 HDMI is said to have bandwidth of 28 gbs).  My Neotech cables are just excellent, so I don't have any immediate reason to move (and they are only just HDMI 1.4 certified!).

Bored today...so I did more research (and looking up stuff I already read).

In trying to compare AVM60 to the 8802a, here are some comments:

http://www.avsforum.com/forum/90-receivers-amps-processors/2004562-official-anthem-avm-60-thread-107.html#post51099217

One of the things that stood out was the AVM60 could be bright/thin and cause listening fatigue. In my R&D experience with analog circuits, this tells me they are using inadequate power supply capacitance and/or cheap quality capacitors than can resonate and be bright.

Other comments have stated Marantz 8802a is superior for 2-channel music. However, if you want/need room correction, it appears AVM60 Anthem Room Correction is superior over the Audessey in the Marantz. Other comments state Marantz is on the warm side when compared to AVM 60.

One thing I know is Marantz puts a significant amount into power supply. Looking here:

http://www.avsforum.com/forum/attachment.php?attachmentid=521905&d=1422970676

The 8802a main power supply has 4 x 10,000uf capacitance, which is huge for a processor like this. Looking at the DAC board:

http://www.avsforum.com/forum/attachment.php?attachmentid=530641&d=1423259930

We can see that they support the DAC circuits with a very good number of capacitors. This ensures that the DAC chips as well as the DAC I/V op amps have very good local capacitance to pull on for fast transients and a large reservoir in the main power supply for bass/midbass power.

The op amps used in the 8802 I/V section (above the DAC chips) are NJM8080G:

http://www.avsforum.com/forum/90-receivers-amps-processors/1535197-marantz-av8802-13-2-xlr-pre-pro-official-thread-54.html#post32165305

These have a very slow slew rate (5V/us) when compared to the typical op amp in analog circuits. This could be used on purpose to give the Marantz its slightly warm sonic signature. In my R&D, 20V/us is about the perfect slew rate for audio. It’s fast enough for high frequency response, but not so fast that it loses bass/mid-bass power. This is probably the only negative thing I see about the Marantz design. This slew rate could also be the reason some people say Marantz is warm compared to AVM 60. But it could also be that Marantz has so much in power supply that you are hearing a full bass/midbass sound instead of a lean / bright sound.

Another point between AV7702 and AV8802a is the main power supply. The 7702 is half the size with only 2 x 10,000 uf capacitors. Also:

http://www.avsforum.com/forum/90-receivers-amps-processors/1535197-marantz-av8802-13-2-xlr-pre-pro-official-thread-46.html#post31643465

It appears that 7702 only provide +/-10.5V to analog circuits instead of +/-12V of the 8802. This is a very small difference, but a difference none the less.