Are the head and cab separate props? There is a wierd buldge at the bottom front of the head that I don't think should be there.

If they are separate props, you might have to tweak where the cab is meeting the head. If they are not separate props, then I am lost.

This is a pic I found of a mkII amp head, which I believe is the JCM head you have in the render. See what I mean about the front bottom of the head?

If I had a nickle for ever time a woman told me to get lost, I could buy Manhattan.