A few years ago i got a Marshall VS65R (i know its not very good but i got it cheap). Recently when i turn it on i get a loud crackling noise through the speaker, this lasts for 10 seconds up to 2 minutes. I changed the valve but this didn't seem to do anything. I tried a different speaker, still the crackling noise. The crackling seems to happen before the valve starts to glow, eventually the crackling stops and the valve starts to glow. This noise occurs with nothing plugged in and all the dials on 0.

Any help would be much appreciated as I would like to fix it myself if possible. I suspect taking the amp somewhere to get it fixed will cost more than the amp is worth!
fuse maybe? the caps might be going on it.. did or one of your friends spill anything on it?
Grammar and spelling omitted as an exercise for the reader.
i tried a new fuse, no change, nothing has been spilled on it. think i'll put a switch in between the speaker and the amp. i'll turn the amp on, let it make its nasty noises, then turn the speaker on
If it was a fuse or caps you would get no sound. Sounds like tube noise to me. Make sure the tube is in its socket good and tight.