crackling sound out of right speaker

Almarg, at the amp, I switched the left and right speaker cables so basically, left is right and vice versa.

If the problem stayed in the right speaker when you did that, and given that you've tried a different set of speaker cables, and assuming that there has been no crackling from the left speaker at any time, there are only two possibilities that occur to me:

1)The speaker has a problem, as Brf and Lew suggested. Perhaps there is a short in the speaker, that is causing the amplifier to have problems that in turn result in it supplying a crackling "signal," even when no music is playing.

2)The cable going to the right speaker is in close proximity to some source of radiated interference (RFI/EMI), such as a power cord, and that interference is entering the feedback loop of the amplifier (assuming it has one), and causing the amplifier to output a signal which causes the speaker to crackle.

I don't see how the problem could be caused by a defect in the amp or the preamp or a source component, given the findings you've described.

Regards,
-- Al

Just to be super super certain, when you switched speaker cables, the amplifier and everything upstream from the amplifier, that was driving the R speaker was then driving the L speaker, and vice-versa. If that is correct, then what I and Brf and Al have said has to be the case. Al brought up the interesting possibility that the speaker cable was picking up something. That's kind of a "zebra", but possible. (In medical terms, a zebra is a very rare cause of a common symptom or finding.)

I have a feeling this is something very simple going on in the speaker, but it depends upon your experience and sense of adventure whether you can fix it yourself. My advice remains the same: get your dealer involved if you have someone local. Why not call the US B&W representatives, if you have no local help?

I'm going to try moving some power cables that may be causing RFI/EMI and see what happens. Assuming that doesn't work, I'll reach out to my local dealer and see what they can do.
Thanks for all the great information and suggestions.

I'm going to try moving some power cables that may be causing RFI/EMI and see what happens.

Also, try turning off any dimmer switches, fluorescent lights, or compact fluorescent lights that may be in the vicinity of the cable to the right speaker.

Lew -- thanks for mentioning about the medical meaning of "zebra." Hadn't known that previously.

Regards,
-- Al