The cable from the 5150 to the Firestudio is brand new, but i guess i should check it anyway.
Also, the head is connected to a 4x12 cab at all times, and it sounds fine through the cab, although i get feedback very easily, even when i have post gain set at 1.
I put in new JJ tubes a couple of months ago, so bad tubes shouldn't be the problem...if i didn't fuck up while installing them.
What do you med by the Send Output being activated?
What you call pain
Is only a shadow