We can work this out with a little more information. I'll assume that, by 'ampjack', you mean a Vox-type micro amp mounted on a jack plug. Using that assumption, then, we'll try being a bit systematic about this. Taking the following combinations, can you give the result of each, please..?
Casady -Lead 1 - Amp = Buzz..? Silence..? Plays OK..?
Casady - Lead 1 - Ampjack = Buzz..? Silence..? Plays OK..?
Casady - Lead 2 - Amp = Buzz..? Silence..? Plays OK..?
Casady - Lead 2 - Ampjack = Buzz..? Silence..? Plays OK..?
Ibanez AE8 - Lead 1 - Amp = Buzz..? Silence..? Plays OK..?
Ibanez AE8 - Lead 1 - Ampjack = Buzz..? Silence..? Plays OK..?
Ibanez AE8 - Lead 2 - Amp = Buzz..? Silence..? Plays OK..?
Ibanez AE8 - Lead 2 - Ampjack = Buzz..? Silence..? Plays OK..?
Over to you ...