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Speaker hum problem - need help

I've searched the forums and have seen past posts for this topic, however, I've yet to find an answer that fits my situation.

First, here's my equipment:
Coda CSib integrated amp
Ayre QB-9 DSD DAC
Auraliti PK-90 USB server
Dynaudio Focus 380 speakers
Audience Au-24 speaker cables
Cardas Clear XLR interconnects
Cardas Clear & Grover Huffman power cords
Wireworld Platinum Starlight USB

Here's the problem:

With only the amp plugged into power and the speakers connected, I get a 38 db invariant hum coming out of the speakers. The hum does not change no matter what the volume is on the amp. The hum does not change regardless of whether I have the amp plugged into the: wall, a power strip, or a power conditioner. The hum does not change regardless of power cord connected to it. The hum does not change when I plug in the remainder of components and cords into my system.....it is invariant.

I have tried to "lift the ground" with a 3/2 cheater plug, but this had no impact. I sent the amp back to the factory to be checked out and slightly upgraded; they could not reproduce the hum at the factory. A previous amp (tube) produced the same issue, however, with the tube amp, the hum got worse as the volume was raised.

I love the overall sound of this system, but this hum is definitely getting in the way of my enjoyment. Any thoughts out there about what is causing this problem and how to correct this issue?

Many thanks,

Matt
mwsl
pbnaudio's avatar
pbnaudio
1,613 posts
 
Have you tried to move the amp to different location in your house along with the speakers to see if the problem persists ?

Best of Luck

Peter
kjweisner's avatar
kjweisner
293 posts
 
I would double check the outlet wiring--if you don't have one already you can get an outlet checker for about 6 bucks at nearly any hardware or home improvement store. It verifies that hot, neutral, and ground are all correct. If no fault in the wiring of the outlet, I would second the idea of a long extension cord and trying a few other outlets. If nothing else, it rules out a variable. Then I'd swap out speaker cables as the next experiment, again, to rule out a variable. If none of that has a positive outcome. . .then I'm out of ideas, but plenty of smart people here! Good luck.
justlisten's avatar
justlisten
489 posts
 
If I were in your shoes, I'd ask my neighbor if I could bring my amp and speakers to his home.

No hum there, you know you have an ac issue at home

If hum there, you know one of two pieces are bad

From there would swap different speaker with same amp, ...you get the picture.
wescoman
117 posts
 
Just a thought - make sure you don't have any halogen lights with variable dimmers turned on while using your equipment. That definitely affects my equipment.
mwsl OP
52 posts
 
Sounds like many of you are concerned about the "health" of my outlets. The house was brand new in 1990....meaning all new (to code) electrical at that time. I did install both audiophile outlets myself....and know they were done correctly. I do have a halogen cable lighting system installed in the living room, and the transformers live in coves at the top of the walls where the suspect outlets are located. I do, however, have the lighting system completely off when I play music, as I am aware of the noise that the lights add to the system. Is there any chance that the presence of the transformers 8 feet above the outlets might be a cause of this issue....even if the lighting system is turned off? I will start with the extension cord suggestion, and go from there. Thanks to all of you for your suggestions. I'll report back.
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