AC or DC are important differences. If the adapter provides AC and you need DC they're not compatible. The reverse also is not compatible.
It looks like your suply, whether AC or DC, is not regulated unless the voltage range is the result of a deliberate adjustment and not the increase in load. The real question - does the load you are powering require regulation?
If the load requires DC, as you've described and the power supply is DC, as you have described, it might be worth a try. Describe the application and maybe we can help more.