2. amps-preamps
  3. 1434034662

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

Showing 2 responses by erik_squires

erik_squires
16,592 posts
 
Well, yes and no. *Some* hum is caused by a ground loop, and *some* hum is caused by DC on the line, and both of these are cured fairly easily.

You missed the key adjective. "Mechanical". This means that something in the equipment is physically vibrating. This can be heard even with no speakers in the room. I know of no instance when this is caused by ground loops. If you do, this will be a novel situation for me.



Best,
Erik

erik_squires
16,592 posts
 
Well, this is a 3 year old thread, but usually excess mechanical hum is caused by DC on the line.

DC can be caused by dimmer switches, and a variety of digital power supplies, including PC's and fluorescent light supplies.

Removing the cause, or using a balanced power conditioner (including regenerators) will work. Sometimes you may have to go to your AC panel and turn off every single circuit that isn't your stereo to find this.

Best,
E
More to discover