Need a Doctor heir any one help , problem which seams to be only on the line six clean sound thought i had sorted it out 2 hrs latter same  problem back thought it might have been dust in pot may be still , but it does not sound like , it seams clean , thought i had cleaned it white noise sound moved pot around on master problem gone , came back 2 hours in to recording , the amp is a few years old now and has just stated or i have just started noticing its a dramatic change would have noticed it before okay am going to shut it down and try latter any help would be great , not technically minded this way but have to learn changing from a guitar teacher to a player HELP LOLL need this amp to start playing live and keep recording .