During this Covid period I modded the amp myself successfully but took the amp to an actual Mesa authorized tech to look it over and correct anything I may have done wrong.They said I did a great job and they just cleaned up some solder connections a bit. The problem I am having is that if I have my HX Effects in the loop of the Rectifier, as soon as I go to connect a TRS to tip/ring cable from the external channel switching jacks on the Recto into my HX Effects the Rectifier bugs out! It produces a very loud buzz and hum if if there's a ground issue or something to that effect. Channel switching also does not work. However, if I take the HX Effects out of the Mesa's FX loop it then switches channels correctly. It's just that I can't have it in the loop AND also have it connected to the HX for external channel switching. I've tried everything, plugging the amp and HX into different outlets, tried every possible connection, tried with and without the Recto footswitch connected etc. The amp just will not tolerate both being connected in the loop and also having the external switching connected. Anyone come across this? Rev.