Slight "Crackling" noise in right channel of amp


Hello - I just picked up a Musical Fidelity KW500 integrated and it's sounds amazing. However, when I stopped playing the music, I noticed that with the volume dial at about 50% and no source playing, there is a crackle noise that comes from the right speaker. It's not extremely loud, but it's loud enough that I can barely hear the 'crackling' from my listening position (7' away) if I listen for it. The other channel has noise if I get up close, but it's constant and smooth...like it should be.

I have swapped cables and replaced cables to confirm that it is definitely the amp channel that is the culprit, and not the speaker.

Now, the music sounded amazing, but because of this, I can't help but think that this is taking away from it somehow and that it could sound even better.

Does anyone have any idea what might be the cause of this unwanted noise? I plan to call Musical Fidelity on Monday but I'm just fishing for thoughts/ideas in the meantime.

Any feedback would be greatly appreciated.
fatgh0st
I think your KW500 uses 6SL7s in the preamp section. These tubes have high gain and are not as quiet. Do follow the suggestion of swapping tubes from side to side. If the noises follow the swapping, then it is quite obvious.

If the noises are indeed from a bad tube, order some tubes from a reputable dealer. Some people here stated that they had good experiences with upscale aduio. With 6SL7s, I would order platinum grade to get lower noises.

Hope it helps.
I have a crackling sound in one of my speakers. When I switch speaker cables the crackling sound moves from left to right speaker. My equipment is Wilson Watt Puppy 6, BAT VK 51 SE, Levinson 432  amp, and Siltech speaker cables and interconnects. I've been told it's a grounding issue. I'm in the process of listing my equipment on this site so what should I do?
A crackling sound on one side is IMHO more likely a tube issue than a grounding issue. Try switching left channel tubes and right channel tubes and see if the sound changes speakers as well. If it is a tube issue it could be something as simple as a poor connection which might just be self corrected when you switch the tubes. That is where I would start in chasing this problem down. 
It dawned on me that I had all the preamp tubes changed about 4 years ago and have used very little since because the crackling and the technician were driving me crazy. Is it in poor taste to ask for a reference that does quality repair work? I live in Chicago.
I took my BAT VK 51 SE preamp and he replaced the tops on the channel capacitors at a cost of $600. Does this sound reasonable?