crackling sound out of right speaker


I am hearing a crackling noise coming from my right speaker.
I have done the following:
Swapped cables (from nordost to MIT)
Swapped left & right sides (left to right and right to left)
Swapped tubes in the amp
Still I have the same crackling sound when no music is playing on any inputs.
My system is:
B&W 802D
Nordost blue heaven speaker cables (all nordost interconnects)
VTL 2.5 preamp
Sonic Frontiers SFS 50
Any thoughts?
maddog66blue
I am going to be working with the deal on this issue. And to ansswer Lewm's question, I physically switched left & right speaker cables, also switched cables alltogether so I think something is going on with the speaker.
Still the same issue with crackling in right channel, even with new input tubes. I'm over it...selling the amp and buying something else.
Thanks for all your suggestions.
I have an opportunity to buy a rogue eighty eight power amp, any thoughts on that piece?
Both the Rogue and your SF amp are very good. Its probably just a matter of personal taste on which one you will like better. If the crackling is a problem with you amp and you verified that you don't have bad tubes, the problem might be something very simple like an RCA connector or a tube socket. If it were me, I would have someone look at it before I did anything.