I was not able to get the NX1000D repaired. Sold it as is. The little I did get to listen was pretty good but the A800 seemed more accurate which makes since. I believe the NX line has pretty much the same amp as the iNuke line. If your getting a good deal on it I'd go for it. Plenty of power and the NX software gives you some good DSP options. These two amps don't compete in the same space necessarily. The A800 is a studio reference amp and the NX6000D is a pro audio power amp. Both good amps but different use cases.
The NX is essentially a iNuke + impedance compensation.
I don't think you can compare them to the A800 SQ wise.
Correct. I wasn't trying to make a direct comparison. However, after spending some time with the A500, A800 and NX6000D, I can offer the following observations between the A800 and NX6000D. I was able to purchase an NX6000D, locally, that had been used only one time as a guy was getting out of the DJ business. The amp came with the box and still had the plastic on the front panels. At $280, it was worth giving it a try.
The NX6000D. I have it paired with my JBL 530 speakers and have noticed a bit more emphasis in the sound of the mids and high frequencies. Granted, not in an irritating manner, but it is a bit more pronounced than the A800 amplifier demonstrated. The fans? Audible if you're within 2 feet of the amplifier when it's running. Obviously, a fan replacement is in order. For inputs, I did have to purchase a pair of RCA to XRL connectors for my use, but could have also used 1/4" TS connectors as an input option too. For outputs, I did have to purchase 2 Speakon connectors so that I could modify a pair of speaker cables for use with the amp. The amp is incredibly powerful and I currently have the gain settings at about 3/4 and the first level LED indicators are not even lighting up during normal level listening sessions - I usually listen at a reasonable level as I reside in a condominium.
The AD800 amplifier is a solid amp. Good sound. Can use existing RCA cables for input, as well as speakers cables with banana plugs for output. In many ways the AD800 sounds like my AD500, but the AD800 obviously has a bit more power.
Later tonight, I hope to try a pair of Paradigm SB200 speakers for more sound evaluation. While the SB200 has been a speaker that hasn't gotten much praise for its low end, the mids and highs appear to perform quite well with a good sound stage - according to reviews that I've read.