So straight to the point, whenever i turn my amp on it makes a strange...buzzing noise. Thats the only way i can describe it. I've been doing the standby thing before i turn it on all the time, i havent owned the amp long so i thought it could be that the tubes haven't 'worn' in yet. But it hasn't stopped doing it and i've used it quite a bit
at reasonable volumes. the buzzing occurs for roughly 1 - 2 sedconds before it stops.

The amp seems fine otherwise, no noise when i'm playing or feedback or anything, just when i turn the amp on. What could it be?

It'sa Mesa dual rectifier. Im selling this soon so i'd like to know what it is before i sell it.
is there anything else plugged into the same outlet as your amp, at times it causes a cross signal and makes a buzzing noise

also if wires cross
Um no. The only thing i have connected to the amp is the footswitch that comes with it and the guitar. And the Cabinet obviously.

Really? It makes a buzz if wires cross?

I'm thinking of a way i can describe the buzz better...

It's like, when i turn the amp on (even with standby on) It makes a buzz as if it's like, an electric problem or something. I don't know how to explain further. But yeah.
Well it could be electrical interference from anything else in the room really. Usually it's close stuff but I used to pick up the radio on my mini 15 watt sometimes, lol. didn't even have a radio in my bedroom! But amps and most other equipment is susceptible to electrical frequencies.

It could also just be the initial surge of electricity running through the amp. If you're truly worried I'd reccomend a) calling the manufacturer's helpline and/or b) calling an electrician who specialises in amplifiers.
Okay cool thanks for the help.
I dont think it's interference as it does it when i'm at my house or at band practice (huage place, underground aswell).

I'll try calling a technician or something.
So its just a buzzing coming from the actual amp, not through the speakers, for a few seconds when you turn it on? I'm pretty sure that would just be the heaters as they start to warm up the tubes
Yes it's not from the speakers. Just a noise for about 1 second everytime i turn it on.

When it first happend (When i got it) i thought it sounded like a rattle, so imagine a loud rattle noise as well. If that helps.