Looks like some of the output transistors get overheat and having collector voltage emergency cut-off.
Your JM Lab speakers could be the primary culprit (too heavy to drive) your amp having an output transistor problem another words check with the nearest tech and if you can't find one in your area, drop me a note.
Your JM Lab speakers could be the primary culprit (too heavy to drive) your amp having an output transistor problem another words check with the nearest tech and if you can't find one in your area, drop me a note.