Blew a tube so had the EL84's replaced. I used the amp for an hour or 2 and it sounded great. When I went to use it for the second time, there is a crappy distorted sound coming with every pluck of the string. It lasts for a bout 2-3 seconds and then disappears as the note fades.
This happens no matter the amp settings, and isn't the cable or the guitar.
Does anybody know what this might be? A faulty tube perhaps that is still working just breaking down at the beginning of each strum?