Faulty headphone jack

I Recently purchased an ipad 3. After setting it up from a previous iPad's backup, the headphone jack stopped functioning properly. The sound was only audible from one speaker. The headphones function properly as tested with other apparatus. Exchanged the tablet & set the new one up as a new ipad. The head phones functioned properly. As soon as I ran the previous backup to transfer my applications & data, the problem happened again. Any advice, as this is obviously a software / conflict problem? I have tried deleting app one by one but have not been able to find any "culprit" application.