Hi Lawrence...yes it’s a crackle that comes when the volume knob is rotated...absolutely no problem once
a level has been set.I have sprayed it with Servisol Super 10 myself (quite liberally) but to no avail.I was
advised by Musical Fidelity that this is a common problem with the amp and a part or the knob needs replacing.
The last time it was serviced .. by Musical Fidelity..they covered everything internally in a white gunk and I would like this removed whilst it’s being checked over. Thanks Dee