question for Luxman L-590AX owners

I have this one, made my Hi-Fi sound better with blacker background and the hum I had from my class A power amp trough my speakers disappeared, mine is with 8 outlets, beautiful made.
https://harmonydesign.se/produkt/dct-90/
The guy behind the company (Mattias) is very friendly and competent, answered a lot of my questions.
Why not shoot him a mail, sure he can help.

I don't have any hum through my speakers, gryphongryph. The piece you linked may be great, but the idea of buying something from halfway around the world for $1000 and seeing if it makes things better isn't overly attractive to me. When my car has an issue, I don't just start replacing parts at random. There has to be a method to the madness, at least for me.
L.

Here is another such product, about $150 :

https://avahifi.com/products/humdinger-dc-line-blocker


Of course, more expensive solutions are to use a balanced power transformer, which are themselves subject to mechanical hum without enhanced circuitry. :-)

I do want to point out that yes, any lights with little wall warts, especially those with built in dimmers, may introduce DC.  The best way to diagnose this is to turn off everything in the house except your amp and see if it goes away.  Then start flipping breakers back on until the hum reappears.

What happens is that these devices only take power from one side of the AC line, but not the other. This lack of symmetrical power draw causes DC to appear, and then the mechanical hum.

Best,

Erik

The hum issue seems to be fairly common with Luxman integrateds.  I have a 507ux and it also started humming a few years after I bought it.  The amp itself is dead quiet-no sound from the speakers-just from the unit itself.This issue has come up a few times online.  Some people say you need to tighten or put insulation under the transformers.  I have been meaning to write to Luxman about it but haven't gotten around to it since it is doesn't affect my actual listening experience.  Very disappointing though!The new Luxman distributor seems like a much more helpful guy than the previous one.  Hopefully they will offer some suggestions that don't involve Bulgarians.

Reports of Luxmans with hums go back at least five years, probably further.
https://forum.audiogon.com/discussions/luxman-class-a-integrated-slight-buzzing-noise/post?highlight=luxman%2Bhum&postid=78228#78228