The Future of Audio Amplification


I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.
distortions
Ric, really good input (NPI) from you;) and likely why Peter Madnick's AA design got such rave reviews. Owning the DPA-1 (stereo amp) the only tim I notice glare is from poorly recorded discs. And yes, I recall ringing whn I had my KBA 75 with chassis long heatsinks

plga, lucky you. Is it the NC 500 Mk II?  I am close to pulling the trigger on a pair of Audio Alchemy monos for about the same money as the Nord Mk II. Not surprising, it's out of stock. Wish I could hear them. Im in S Florida

https://www.nordacoustics.co.uk/nord-one-se-nc500
Hello tweak1
No, its not the MKII.
I bought it just a few days before the MKII was released because I didnt know! Colin didnt tell me that, otherwise I would have wait for the MKII. 
Nevertheless, this model sounds "superb" with the Sonic Imagery Op Amps. 
To have an idea, Hulgich Audio, an australian speaker factory, won the best sounding stand award on 2017, and second best on 2018, on a HiFi Show in Australia, competing against systems that costed hundreds of thousands and the amps used on those shows where Nord One UP NC500DM Monoblocks. My opinion is that you cant go wrong with the MKII.

plga, I just checked Nords site. It would cost > $2.2k for the Mk IIs. I don't mind the wait, but I can get a pair of AA monos for ~ $1500 (MSRP $3990) and that extra $700 I would need to spend now is a big stretch. I realize that the perceived value in the new amps could pay off at some later date, and that when I sell the AAs, they might further drop in value when I decide to sell
Well, thats something you have to think and decide on your own.
It will be difficult for me to sell my previous 300B valve amp because its an expensive one and in my country (Argentina) there arent many people that can buy it, but I dont care much because, even selling it at a very low price, I should recover the money I spent on the Nord. And Im not even considering the replacement valves I have in stock and I also have to sell.
But everything is now less importante considering that I have now a much better sound, less heat, less energy consumption, a smaller and lighter amp and I wont have to spend on valves ever again. 
Is up to you and your circumstances. 

It is always best to have dual mono......so here is a link to a review from a person that owned the mono Nord one up amps (with the Sonic Imagery op amps) and then bought two stereo amps with the IceEdge 1200AS2 modules in them and then ran each amp as a mono block.....so now we have a fair comparison (fully mono in each case). He says which one he prefers.

https://www.audiocircle.com/index.php?topic=154910.80

Post #97

And this is with stock IceEdge modules implemented in a normal way. Imagine how much better it could sound with tweaked modules and tweaked execution.......stay tuned......coming soon.