How do I use the Headbone VT to switch between 2 heads into a full stack, i.e. 2 4×12 cabinets?
Most amp cabinets have an input and a parallel (or series) output jack. You would connect the output from the Headbone to the first cabinet and then from the first cabinet to the second. If your cabinet is not equipped with a parallel jack, simply build a Y-Jack cable or junction box using heavy speaker wire.