Dodge-City

Hi guys.
Im new to this forum and amps,I havent a clue about the technical end of them.
I got a avt 275 last year and within 4 days it died.All the lights came on but the fans didn start up and no sound came out of anything (line outs,headphones,fx loop)
The guy in the shop was really nice and just gave me a new one.But,and this is my 1st issue.

It was packed with an older model stage controler.I know its the older one cause the first amps footswitch had "avt 275" on it and the one with the second amp says "valvestate2000".Now it works just sometimes it can take a fit and switch the channels by its self,but only for a second.Eg...Playing a nice clean channel guitar riff and the od 2 light on the footswitch starts flashing and in sync with the flashing,the od 2 channel acivates.Is this a common thing with footswtiches/marshalls/new amp,older foorswitch configs?

My second issue.This one is starting to worry me.When you turn on the amp,normally,the fans turn on and they make a small wind sound.this is fine and im not worried about that.Just resently when I turn on the amp,the fans turn on but this is accompanied by a really nasty and aggressive reving/grinding noise coming from inside.I immediatly switch the amp off and on again until it stops.Also this reving noise doesnt effect the guitar signal at all.My amp can still go as loud and all the channels still work and there is no change in tone.Just noise sounds like something is braking.Cound anyone shed some light on this?Also this didnt happen on the first one I had.

My third is rather small.The amp makes a smell...Kinda like burning.I know that theres valves in it,and valves burn(or heat up) but I far as I know arent valves sealed,with gas inside them?So how could a smell get out?Could it be where the plug goes in (I think thats called the transformer,and that gets really hot after Ive been playing a while.)

My fouth is something ive seen on other peoples posts and have said that it has "developed" whereas it has always been the way with my 275s.
The clean channel is twice as loud as the OD 1 and 2 channels.
I think the gain on the OD channels is weak.
Im bad at explaining things so ill give an example.
The OD 1 and 2 channel and the Clean channel all hae there own Gain and Volumes Knobs.
If your playing with the gain up full on the clean channel (so you get that nice really light cruchy brake up sound) you have to have the volumes to 12 o clock(if not less) so that the OD channels can be louder.Also the gain controls on the OD channels dont effect the volume that much,they just make the sound more distorded,unlike the clean channel where the gain increases the volume an awful lot.Also OD 1 is louder than OD 2(I.E when everything is turned up full),which personally I think is silly and im not sure if its a manufacturing problem or the way its made.

The fifth is my biggest problem and has changed the way I have to use my equipment and I really hope someone can shed some light one this.
If you use anything like a stomp box that would boost your guitars signal (Distortions,FX units) and you would connect it into the "input" jack and selected the clean channel the amps responce would be quite unusual...
It only happens at high volumes.At low volumes,everything sounds at good as a Epiphone Black Beauty going through 700 euro of asian DSP (Boss GT-8) should.I only found this out when I was using the distortion and I was playing in a shed.
The Rooms acoustics were crap and the drummer was mental,so I ended up pushing the amps master volume to about 8 or 9 mid song.when we were finished I turned the amp down to 6 and I noticed the guitar sounded like really high frequency noise.
Like white noise on a tv,just abit nicer.All the bass was gone.And the mids and trebles were really pushed up.there was no clarity to the sound at all.I ran to my amp in distress shouting "everyone be quiet,I think I blew my amp."
I switched it off,turned down the master switched it back on and turned the masted to one and everything was grand.Two,grand.3,grand.Got to about for and 5 when I started realising that the amp wasnt amplifying sound.When Id increase the master,it would act like another trebel/mid/presance knob and just make everything sound like crap.
To combat this.I know have to run my Gt 8 in the FX RETURN Jacks.Unforntunatly I cant use the "input".Which means,I now use my marshall as just a power amp for the speakers.
I cant use any of the channels or the amp fx,which I really liked.When I turn up the volume in this way,everything is fine,theres no frequency bump up.I was wondering is there a way to run fx units into the input and running high volumes.Also Id like to say,during that jam session when I had the volume up high,the tone controls wouldn effect the overall noise coming out.

In conclusion.CAN ANYONE HELP!

Im 16 and ive been playing 3 years and this is my 1st(well second if you count the 1st avt) proper marshall.I had an mgfx15 before this.
I only really play a few small gigs and jam sessons in someones garage or in a shed is really, and this amp is all I could want (for when a drummer is a tad heavy handed or when a sound engineer doesnt know your the lead guitarist,or doesn know a thing about sound desks.....at teen gigs....teens run the show.....nuff said.)Im not looking for miricle sounds out of something which cost about 650 euro but Im hoping some things can be fixed cause I know that it can sound better!
Thanks for reading
Oh and everyone on this site usually puts this in.
Im using an Infamous.....Marshall avt275
Epiphone Les Paul Black Beauty
and a Boss GT 8....hahaha
Thanks again,sorry about any spelling mistakes.

amplifier

See my post for you on Marshall Amps.