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Luxman Class A Integrated Slight Buzzing Noise

Hello--

I just purchased my first class A amp--a Luxman 550ax--from an AG member recently. I noticed this morning that when I get close to the amp while it is turned on there is a slight buzzing noise coming from the unit. If looking directly at the top of the unit it seems to be coming from the right middle of the unit. Doesn't seem to affect anything with my Harbeth speakers and I only hear it from a couple feet away. I was wondering if this is normal for a class A amp. Anyone with a 550 or 590 have this issue? Any ideas what could be causing it? I have it plugged into a Richard Gray 400 Power Center using the stock Luxman two prong JPA1000 polarized power cord.

Sources are a PC connected USB to a Fostex HPA8C DAC connected to the Luxman with Transparent Audio Link 100 RCA cables.

Thanks,

Dave
ddinkel
stereo5's avatar
stereo5
6,261 posts
 
Perhaps the bolt that holds the power transformer in place is loose. It could be from being shipped. I would check that out as I had a Classe' amp that did that exact same thing.
swampwalker's avatar
swampwalker
5,138 posts
 
Most likely it is a mechanical noise from the transformer. Could be loose, could be from a slight amount of DC on the power line or could just be endemic to the particular transformer. It should not affect the sound.
digsmithd
913 posts
 
I would personally take it and plug direct to wall...its possible that it wont cure the transformer buzz...class a amps do run a little hotter so ?....
bojack
631 posts
 
Some transformers buzz in relation to incoming power conditions, and this may be what you are experiencing. I had an amp one time that buzzed when an outside safety light came on at nightÂ…buzz went away at 7:00AM every morning. I'd also plug it into the wall and see what happens before you check the transformer bolt.
ddinkel OP
4 posts
 
Thanks all for your input. bojack, you may be onto something with your suggestion of incoming power conditions. I haven't been able to fully investigate and haven't plugged the unit directly into the wall yet but it definitely seems worse when I play music in the early morning. I'll look into it more this week. Again, thanks all for your help.

Dave
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