Doepfer

hi list,i really need your help here,i bought 2 more a131 vca's 2 
weeks ago,and i used them yesterday for the first time.today ,as i 
did some extensive tests with the a131's, i discovered that they BOTH 
have exactly the same problem.when i turn the INPUT and the OUTPUT 
knobs fully clockwise,they sound much louder than my other (older)
a131,and my (also,older)a130,(with the same knob settings,of course)
and the most important is that they sound distorted,a little bit,but 
it is still quite annoying!!!are they broken?do they need calibration
(or,anything else?,i know nothing about electronic circuits...).the 
wierd thing(that might mean that they are not broken...)is that both 
my new a131 vca's have the same behaviour(or problem...?)...
please help!!!!!i am really sad...
synthfreak