Stay away from the nad

I would think NAD/Lenbrook would be helpful. I called them to talk about parts for my PSB speakers and they were fantastic. I also called tech support for my Bluesound Node 2 and they had a real live Canadian person on the telephone to help troubleshoot. They solved the problem in minutes with professionalism.

I also have an NAD M51 DAC. It’s been flawless, but maybe a year old at best. It’s quiet, well built and does not seem to be laden with cheaply sourced parts.

The OP’s predicament is frustrating. It’s also either indicative of some really bad luck (as he/she had 3 NADs fail) or a real quality control problem.

My experience in the past 2 years with NAD and Lenbrook has been fantastic though.

NAD used to be good stuff.  I am sorry to hear your experience.  Why did NAD not offer to make it good?
I enjoy my 45 year old Crown International DC150A series II   everyday.  Also use a 40 year old Crown SL1  PL1 every day.  Still sounds great.  Both still hit lows hard and clean highs. No service on it since it was purchased. Can anyone beat that for reliabiliy?  It will be fun to hear.  

Apparently Djeng prefers complaining to strangers on the internet to contacting Nad to see if they’d warranty his broken 356. 

Call them.  Get a real live person on the phone.  Explain that you are a repeat Nad customer.  Be friendly.  Have your receipt that proves it's only a "couple of months" out of warranty as you've stated.  Ask if there is anything that they can do to cover this under warranty on a one time basis.  If they say no, politely ask to speak to a manager about this unfortunate situation.  Report back here with the results.

It meant to be advise not complaining. No help from nad.

Sorry for typo. "advice". Yes, I contacted nad and the first question was "is the unit still in warranty". When I said no I've got the answer "Sorry for the trouble". Any further conversation with them was over.