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question for Luxman L-590AX owners

I own the subject amp, have had it for 3-4 years. I recently noticed a low hum or buzz coming from the amp itself (not the speakers), and would swear that it has been dead quiet up until now. You have to have your head right down beside it to hear it. I'd like to hear what other owners have to say. Are your amps completely quiet? Seems like I may have developed an issue. Thanks in advance, and Merry Christmas.
builder3
ryder
1,690 posts
 
No hum but I’ve trigerred the protection circuit several times now as the amp automatically shut down by itself. The system was played continuously for several hours, sometimes above 10 hours in a day when it happened. At least I am aware the protection circuit feature of the amp is working and the unit is protected from the heat that it produces.

It sounds magnificent by the way.
tommd's avatar
tommd
10 posts
 
  1. Buy a DC blocker in Bulgaria , it works fine for me . I,ts a small 122,- dollar investment. Be sure to order the right version...Be sure to order the 2v 6 diodes version.https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/
gryphongryph
392 posts
 
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.
builder3 OP
765 posts
 
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.
erik_squires
16,330 posts
 
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
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