I'm getting a slight hiss or crackling noise in the left cup of my 650s when changing the volume on my Fiio e09k or at certain bassy points in various tracks. As I've said it only affects the left cup and only sometimes. I've had the set up a while and ignored it at first as it was a minor annoyance but it's getting to me more and more as I'm used to the sound.
Is it a faulty amp, or is the amp just not good enough? I really hope it isn't a fault with the headphones as I'm not sure what my warranty situation is now (they're about 18months old).
Thanks in advance.