I am pretty sure it is a different footswitch so I don't think it would work properly. Otherwise why would htey even bother to make two different versions? The FU-2 and FU-2A are the proper footswitches for you to use with your quad. Be sure you get the right one for your amp. At some point they switched from the 2 to 2A. I have heard that the quads will not work with the wrong version. Call Mesa with your serial number and they can tell you which version you need. Then either buy a new one (recommended for issue free use) or buy a used one (and chance having problems). I am not sure that they still build an original FU-2 but you might get them to modify one of the current 2A's for use as a standard FU-2.