wolbai
Member
These things strongly suggest that your guitar is picking up electromagnetic interference from something nearby. It's not hum, and it's not hiss; it's interference. And it's coming in through your guitar; it's not a ground loop.
The fact that the noise goes away when you touch the strings suggests that there may be a grounding issue in your guitar. It could be a broken bridge-grounding wire, or it could be something else.
The short-term fix would be to hunt down the source of the interference, and turn it off. It could be the amp. or it could be something else that your pickups are pointing at — either in front of them or behind them — when your guitar is facing the amp.
Well, there could be more than one source for the unwanted noise as already mentioned (and I am not really sure anymore, if we are talking about the same type of noise ...)
Nevertheless:
To get a Marshall JVM410h quite while playing on the OD1/OD2- channels in Orange or Red mode at rehearsal/gig volume levels, Noise Gates (or an advanced playing style that is cleaning up the noise with the guitar volume knob during breaks) are a must IMO.
Because that is how I got my guitar rig quiet to do also recordings with it. And that is what I have heard from other players with a comparable rig as well.
The specific parameter settings are likely to be different from guitar rig to guitar rig. Therefore I still recommend to set the Noise Gates the way I have described above, because you will have to use them anyhow, regardless whether there are additional (interference) sources that generates unwanted noise or not.
Check also my suggestion with the Clean Green channel! If there is the same unwanted noise (Hiss/Hum) as well, then the root cause seems to point (also) to additional (interference) source(s) IMO.
wolbai