I did the low power mode mod to my Class 5 combo last year. I pretty much play it cranked thru the headphone jack into a 4x12 cab. I hadn't played thru it in awhile and today noticed it sounded like crap. Thought maybe it was the speaker so plugged it into the 4x12, still sounded horrid, like a rattling truss rod only I plugged in several guitars and it did it with all of them
I then switched it back to normal and ran the 4x12 thru the normal extension cab jack and it sounded great again. I had thought I had microphonic tubes or something going on, but why would it clear itself up just by eliminating the headphone jack?
Anyone else experience this with the low power mode? What would the best guess be as to how to fix it? I am starting to think that headphone out wasn't really designed for and tested enough for what most of us have been using it for..................?