My Savage has some crackling - tubes issue

[::XeS::]

Hi
It's 1 month that I hear some cracking when I use my Savage.
I hear these noises when I don't play the guitar (but it has the volume maxed).
Initially I thought it was a cable issues but it's not.
Today I noticed that when I raise the pre gain, the crackings increase volume.
I recorded a little clip: Guitar and cables are fixed so there aren't jack or cables movements.

http://www.sneapforum.celtiaproductions.co.uk/::XeS::/Crickcrock.mp3

You can hear when I move the gain pot and how the noises increase.
I think it's a pre tubes issues but if you have some idea, you're very welcome

Thank you

 

[Razorjack]

Take it in for a service, it might just need a good old clean.