I bought mine off ebay last year, but never got to use them for 4 months due to working away on nights.
Same problem with crackling in left set.
The guy who sold them obviously knew this, but my mistake.
Phoned bose. They said never heard of a problem like this. What lies people tell you in order for a sale.
Looking at this and other forums anout same problem, bose obviously know about these issues.
Well I have all bose systems in my home. No more though. This will be the last time I ever buy bose. After service is crap!