I recently bought a DT50 and love the sounds with My music man Sillhouette, and the JTV 59P, but I have 2 issues that may be nothing, just need some thoughts from you all.. 
  
The Amp is noisy and hums. I have read using better tubes (vales in my neck of the woods) has helped many who have had hum and noise/hiss issues so I think that will be sorted once my TAD's and GT tubes arrive.. Yes/No? 
  
Second, one of the screws on the top that holds the amp chassis into the cab, one is missing the washer and the screw has been screwed into the cabinet. I know I could unscrew it and get a washer, but what bothers me is that this might have been a repair and not put back properly. The amp is only a few days old, Any thoughts? (photo attached) 
  
Lastly, the amp sometimes 'thumps' when changing topology, is this normal? 
  
What I don't want to do is have an amp that will deteriorate in the next few months, but if these issues are 'normal' and only cosmetic then I am happy to keep it. 
  
Thanks in advance 
  
Chris