Stay away from the nad

donjr,
Of course. With the right interconnects nad can sound very good but their reliability is terrible. I live in New York. Service centers charge $150.00+per hour for their service plus parts, if necessary.
It is not normal that 3 amplifiers failed in five years with the moderate usage.

+1 to bad NAD quality.

NAD M51 DAC, after about 1.5 years of use USB-in stops working (others works). Service said it's motherboard issue and price to repair comparable with the new unit.

I concur with the panel that NAD took a big hit when it junk-sourced to china. I wanted to buy into the Master Series, changed my mind quickly due to reported QC issues.  The older NAD from 80's and 90's is very good in comparison.

I have had a number of NAD products, amps, preamp, tape deck, receiver and none had ever failed.   A few years ago I bought a M51 DAC and it took a dump during a firmware update after only three weeks of use.  Was it my fault? Bad firmware? Bad hardware ?  Who knows but NAD sent another one to Spearit to for an exchange.  They could have easily said send it in for repair,  but they didn't .   I would buy another NAD based on that experience and how great that DAC sounds.   

Hi.  Older duffer with about 40 years in "the chase."  Sorry about your experiences with NAD.  A few years ago, I had to make a tough call.  Had been using a modded Moscode 300 with great success (left up full time) that bellied up.  I listen nearfield in a small room and am highly critical.  After much search, I found a clean MUSE 160 from a Gon member with a great track record.  A couple months in, fireworks from the right channel...surprisingly, the other channel kept playing until I got to the switch.  Now what?  Years prior (about 7 now) I had read strong positive reviews about the NAD M2 digital box (dac/pre/amp) ...strong across the board around the build, innovation, and of course, the sound.  Full retail was $6k, beyond my means.  And, yes, I also had heard the negatives around NAD's service ills.  Well, as these things go, I was able to find a used one within budget, a tough call considering my recent experience with amps.  So far, the gamble has paid off richly.  Since then, I also landed an 80's NAD 3140 integrated for the bedroom that has a terrific headphone section.  That piece is now driving my son's system, the heart of his recorded music and solid body guitar playback.  Folks, this hobby IS a gamble in my experience.  I left an Electrocompaniet Ampliwire II (which had a British sports car reputation) on for 20+ years with no issues, VENTED PROPERLY ON ALL SIDES.  Remember always, heat is the enemy.  Good luck with you future choices...it's all worth it in the end.  Best, Norm