But what does it actually sound like?
Q. Is there a low frequency rumbling noise that is there all the time, even when there is no audio?
Q. Or is there a "roughness" to the sound? Almost like a scratching?
Q. Is is present at medium and high volume too?
Q. Does it change as you alter the treble and bass controls?
Answers to these sorts of questions help enormously. I know it might not be easy, but it's really worth taking the time to learn how to subjectively describe the symptoms, especially given that we are unable to hear what you do. In this thread you've probably had every possible fault condition possible (apart from the amp being completely dead), so at least every base has been covered, but a better description would have resulted in more targeted, concise advice.
Your description of what happened when you tried parts from the Hunter was very helpful, but none of that described what the faulty amplifier sounds like.
I hope that helps
Mark