Hi guys I just bought a Laney VC30 from e-Bay which is new, only purchased a few months back, took it home and noticed that there is loud hissing when I turn the Drive + Drive Volume past 4 which gets progressively louder the more I turn it up.
I have a Fender Jaguar re-issue with original pick-ups, could they be the problem, or is it something wrong with the amps or tubes?

No I haven't... But I will try...
So you're saying leave the other end of the cable in the amp and just unplug it from the guitar?