Adcom makes a fine amp and if you are happy with the way it sounds with your speakers, keep it. I have Carver amps from the mid 90s that sound awesome that I plan to get refurbed and will continue to use.

Balanced connections are XLR a connections and are regularly used in pro applications and a lot of higher end equipment. Your Adcom does not have XLR inputs so this is moot for you unless you want to get a new amp. Reality is, balanced connections don't generate the ground humm you sometimes get from a power amp and pre amp. This is driven by cheap cables. If you get a high quality RCA cable and it is short, you can avoid this issue most of the time though equipment still suffers. XLR cables never suffer from that humm regardless of wire length, even runs over 25 feet. Quality of the cable also seems to make minimal difference with XLR a cables.

Regarding the Pre/Pros you mentioned above, both the Emotiva and the Outlaw are quality products that have HDMI inputs and Dolby TrueHD. I am not sure how the room correction is on those and whether it is a quality version of Audyssey do their equivalent. The Marantz you mentioned has way more features than you seem to want or need and the Emotiva and Outlaw units are not in the same league.

I have a Marantz AV7005 which was their pre/pro from about 4 years ago. It has a great version of Audyssey, superb video processing and the ability to adjust the interface via your network and some other features that I like a lot. You might be able to find a refurb off from accessories4less or a used unit off of Audiogon. It will do everything you need.

The only other thing you need is great cables regardless of the unit you pick. Audioquest makes great ones.

Good luck to you

The Adcom lacks Audyssey room correction which makes way more difference that you would think. These dynamic EQs automatically adjust levels and optimize 5 channel sound for your room. Additionally, the Adcom doesn't support Dolby True HD or DTS HD.

The one strike against the suggested Marantz AV7005 is that it doesn't support 2 subwoofers. That would be the biggest advantage of one of the newer Marantz Pre/pros like the AV7701. I would check accesories4less and see if a less expensive refurb might be available.

Regarding the humm, it is possible that your cables are driving it. You can try upgrading to Audioquest or Kinder or Acoustic Zen cables. They may eliminate that humm. Alternatively, it just might be the nature of that amplifier. This is tough because you can spend $200-$300 or more on new cables and it might not make much of difference. A Marantz MM7055 is 140w 5 channel balanced amp. I think you can get a refurb for $549 from accesories4less which is Marantz's clearing house for discontinued and refurb items. I have my AV7005 paired with an older version of that Marantz power amp and it sounds great.

the Cinema Grand is wonderful power amp with double the output of the Marantz. I have low sensitivity speakers and am under powering mine a touch which is why I am thinking about the Sunfire. It sounds fantastic and should have balance inputs. For the money it is a fabulous power amp and I would take it over a Marantz any day.

If you have any questions about the AV7005 after you get it, let me know. I am obviously extremely familiar with it and I am not sure if the instruction manual could have been more poorly written and I use just about every feature that it has to offer.