+1 hereLOL. good point Yek! I HAD to read this one for obvious reasons. That being said, it does bring up an interesting point. I am currently using a Line6 G-50 wireless to feed my AXE 2 black box. Does anyone know if front or back inputs make a difference with this particular wireless system?
Some wireless receivers have an XLR line level output.
Because the rear inputs are designed for line level signals, not guitar input. In Metallica's case, they are using wireless, so the input going into the Axe II is line level (from the wireless unit's preamp). The wireless unit between also acts as a buffer in front of Axe II's input, so the secret sauce variable input impedance circuit would be of little use. They also use mostly active EMG pickups as well, which also have a low impedance buffered output.
This.I'm not sure about wireless receivers outputting and line level. That doesn't make any sense to me, as running a line level into a real amp would overload it easily.
It's probably more about buffers than levels. A wireless receiver's output is probably closer to a buffered instrument level than anything line level. The presence of the buffer therefore makes the secret sauce irrelevant anyway since all the input-Z stuff only works when you plug a guitar directly into the front.
Try plugging your guitar into a non-true bypass pedal and then compare the front and back inputs for yourself.