Question about DSP in a Line 6 spider III 75 watts amp

[mindtwist07]

So here's the question:

      My amp is a line 6 spider III 75 watt solid state amp which is mainly digital and all its programs are DSP based (have read in some forums) its power is 110V. Three weeks ago a friend of mine accidentally plugged it to a 220V output which quickly gave smoke at the back panel of the amp. I plugged it again using a 110V transformer. The amp turned on however you can only hear a large amount of feedback and hum in the amp. It turned on so there's no problem with the transformer. Ive read in another forum another guy who has the same problem with me and trying everything to fix the amp. He saw some burnt marks on the back of the PCB of the amp mainly the DSP chip. He had it replaced however he encountered some abnormalities on volume and tone. Do you have any idea about this?