Wharfedale PowerCube PC-12 Subwoofer Problem

ok , what your going to need to do is give me the numbers on the amp IC's , and i will see if they are available , but first you will need to see if the pre amp transistor is failing , to do this leave the power off and unplug from the wall then with a digital multi meter on diode check , check to see if the emitter to base reads about 680- 700 , if it does then its ok but i would replace that anyway because it could be the reason the amp is not amplifying correctly , sometimes they don't act up untill power is applied , then also replace any resistors in line with the input line that do not read thier values( if you need help identifing them let me know and i upoad the codes for them) and also the electrolitic capacitors on the transistor line to the amp
once you have completed these steps let me know if there is a change
you can cross reference you transistor here also maybe the power amp http://www.nteinc.com/