I just got done putting my 1981 Music Man RD back together after replacing a bad cap, new speaker and new tubes. I plugged it in and pop (at the outlet the second I plugged her in), smoke coming from the amp (no distinct smell). It wasnt turned on or anything, just blew as soon as the plug hit the outlet. I dont think the repair had anything to do with it because ive played it several times since the repair, just with the chassis removed. All i did today was put the head back into the cab and put in a new speaker - 8 ohms to an 8 ohm input. Any ideas on what can cause it to immediately blow when plugged in while its turned off?