Korg Poly800/EX800 Users

I just got my Poly 800 mk1 in the mail today. I got it off ebay so i 
guess i should've expected problems. I set it up with a 9v power 
supply i had lying around(same - and +). Anyways i powered it up, 
turned all the tape stuff off everything worked fine i can switch 
pathces edit params and whatnot, BUT. I plugged it into my guitar amp
(all i have at moment) and the volume was at full and on ANY of the 
presets i get either a sweeping filtery noise(very low volume on 
this) or on some patches if i move the joystick down i get a weird 
wobbly sound that's pretty loud.so i figure that the problemn isn't 
my pwoer supply or my outputs, but what is it?