markny - I never said that Samsung ownership has no impact on Harmon Kardon and thus Levinson. I simply said the Harmon Kardon is a pretty well respected company.
The issue with 3xx series amps is that they used specialized filter caps that ran at very near tolerance. Those caps eventually fail. Those caps are no longer available, although there have been some replacements available from other sources. But experience has shown that many of the replacement caps also fail. There is a design issue with the amps and a supply issue for the caps. A $2,000 repair with parts you do not trust is a bad business decision. There is more to this than just that Samsung is cheap. Not having replacements parts is a pain, but it is not unique to Levinson and Harmon Kardon and Samsung, as in my Thermador/Bosche example.
That said, I will never buy a Samsung appliance because I do not trust their service. But Samsung phones are all I buy.
EDIT : Samsung bought Harmon Kardon in 2017. This issue of getting Levinson 3xx amps repaired predates that purchase, for the reasons stated above.