I replaced the Pre-amp tubes...and guess what ?..It is still making some pretty scary sounds..( frying eggs,squealing,pops,) I'm ****in' freaked out here !!I did the pencil test and tapped the tubes with the eraser and got some "Microphonic" reaction on only one tube,I then changed that tube and the symptoms ceased.But now Iv'e got some Squealing happening in there ! WTF ? Do I need to get this baby serviced or what ??? One very Puzzled guy...--L.B.Thanks guys .