I always have troubles with my amp.. Here what's I got : - Ashdown ABM500 evoII (575w) - Mesa boogie 15' roadready cab (I broke the speaker and remplaced it with a 600w one, I have to buy a 400w one cause I thnk the cab is too little for that power ???) - Mesa Boogie 2x10 cab (only 200w, too weak for stage, only for room practising..) - 2 Musicmans I had several troubles with the Ashdown, I send it back several times, the last time, they put it on oscilloscope and said that it was prefect, but when I plug it, I still hear a little noise on the sustain of the note.. Result : A noisy head, a cab with not the right speaker.. A bad sound... What would you do if you were me ?? What reparing first ?? What changing in my gear ?? Help me.. I will soon have money to spend in my amp system..