I originally purchased D400's in late 2015. I consistently had problems with them shutting down when playing at louder than normal levels. It seems that the 3.7i's and D400's were not a good match.

One year later (Nov 2016), Devialet replaced my D400's with the newly released E440's. This replacement was completely initiated by Devialet, and at no cost to me! The first release of the E440's did not include the Core Infinity functionality and some of today's current features.

In mid-August this year, my NAD M17 SSP died (bad PS). While it was in for repairs and an upgrade to V2 status (WOW, BTW), I was browsing on Devialet's web site and saw that my E440's were eligible for an upgrade to the latest architecture, again at zero cost to me!

Devialet sent me new shipping boxes and the necessary paperwork and I shipped the amps to France on Aug 31st. I just received them back this past Wednesday. There were some shipping issues, but Devialet's Customer Service (Shanna) stayed on top of everything and kept me informed. I could not be any happier and appreciative. They are still breaking in but from the outset, the upgraded E440's definitely sound more powerful and quieter than the originals.

Devialet replaced my D400's with new E440's, then upgraded my original E440's four years later, all at zero cost to me! Customer service at its finest!