This is going to be one of those cases where only someone with the same set-up will be able to give you a definitive answer. It depends on the amp - and the TV - and the geometric relationship between the two.
For what it's worth I have a small, cheap, Sharp 14" TV, that I use as a second source monitor, sitting less that a foot from the top of a Carver A-400X amp, the only thing separating them being a woodden shelf and air. When I first plunked the TV down I did notice some mag field effects. I rotated the TV several degrees and moved it back on its shelf and the noticeable effects disappeared. Since I only use it for non-critical viewing it's not a big deal in any case.
You can only know for sure by trial and error.
Jeff
_________________________
Jeff Mackwood