I taken to lab but presently oscilloscope not available, so one of professor checked output to the speaker and found 1.34v so STK is damaged.\nPresently in my place I checked all shops not available\nCan u suggest me any other equivalent ic.\n\nThere is no equivalent. Nothing cross references. That is what I found out at the start of this. Mouser don't have it. It is listed on Digi-Key,t he world's largest supplier of electronic components as obsolete and no longer available. So they will never be available again. \n\nThis is the problem with ICs. There is usually only 1 production run and when they are done they are done.\n\nNow you have made a good effort, and it seems you are in school. \n\nSo this is the end of the road for you unless you want to design a totally new IC power amp to run off that power supply as a class project. Now you are above my pay grade, but may be one of your professors can help. The difficult part will be duplicating the motional feedback part as we do not know its characteristics. So this is probably a next to impossible endeavor.\n\nIts new sub time, I'm afraid.