Weird buzz sound when turning the amp on

[Disfigured]

Hey, I've bought Mesa Dual Rectifier quite a time ago, about six months from now. As I live in Poland our ground voltage is 220V, so I have to use the transformer so that the amp won't break before I have a chance to hit any note. Everything works fine I guess, the amp has its moods and sometimes it plays really well, but there are days that it sounds very crappy, but as far as I'm concerned it's the matter of dumb user, not the amp.
The issue is different, every time I turn on the transformer and then turn the amp itself on there's a strange buzz sound. It's literally like "bzzz". What got me concerned is that it was always kinda long, like 0,5 half sec - a "bzzzzzzz zzz" coming out of the amp while turning it on. I didn't really give a **** as amp works as it was scheduled to work and after boosting it with the OD-3 my mind is blown by the weight of gain and bass.
What concerns me is that since yesterday the sound changed, there's only quick "bzz" while turning it on. Is this normal and is it any kind of danger to the amp?
Cheers.

 

[elvis]

Buzzing noises are quite common, and may be either mechanical or electrical.

Mechanically, the high electromagnetic fields in the transformer can cause the coils and/or housing to vibrate. This often happens for a short time as the initial current draw of the transformer is very high, but drops to a more controlled value quickly, once the DC supply capacitors are charged. This is why "SLO-BLO" fuses are required.

There can also be electrical coupling, as the high fields in the transformer transmit to the sensitive amplifier stages, either through ground loops or through the air. These tend to be more constant, but again, are worse during the high initial current draw.

Your situation is worse than most, as you have two transformers. Several things may be causing what you hear, including the location of the external transformer and the actual outlet the amp is plugged into. It is unlikely that you are having a real problem if the amp works OK. More likely something about the setup has changed (different outlet, part of the system moved, different settings, different outboard gear, etc). The only thing I can think of that might be electrical would be a shorter charge-up time, which would only be possible if somehow the internal capacitor values were reduced or the start-up current of the transformers was larger. Did you change to a higher power step-down transformer?

In short, I doubt you have a problem.

 

[Disfigured]

Woah, I completely forgot about that thread.

Let's get things straight then. When I changed my Rectifier's power socket I must have had moved something in the room's corner as the transformer's plug loosened a bit. It resulted with nothing more, but a shorter buzz sound when turning on or.. maybe a LITTLE bit dull tone. I had found that out and plug it tighter so everything came back to normal.
This is the sound I get when I turn my Mesa. [sample] Nothing seems to change, though it's the second Rectifier I have played in my life so actually I have never heard this kind of amp turned on and set to my liking nor had even a chance to tinker, but as long as switch to Orange/Red channel I get a really cool thrash tone and after boosting it with BOSS OD-3 I finally achieve my beloved brutal death metal tone which is absolutely what I expected.

Has any European user ever encountered such situation and can someone send the "proper" Mesa switcihng on sound?

@edit
Today weird thing happened. I turned the amp on but there was still buzzing sound coming from the tubes. I switched the amp off and turned it on and what's interesting there was no buzz sound at all. Maybe it's the transformer's fault or something?