I was considering putting shorting plugs on the variable outputs of a vintage Mac tuner (MR77) that I have coming. I'd use the fixed outputs. The matching Mac integrated came with shorting plugs on second phono input, after all (the fallacy of arguing from similarity, like eating rhino horn pre-Viagra.) Maybe this would help keep RF noise out of the inside of the case and so into tuner circuits and make for a quieter sound quality. After considering it for a while I realized this was a VERY stupid idea. First, the outputs are driven by an amplifier stage so the level is fairly high voltage level. Shorting an amplifier output is also asking for trouble - they are made to drive a load. The Mac engineers probably made this idiot-proof anyway so I doubt I would have damaged the units. I did realize, after consulting the schematic, that leaving the variable output volume on the lowest setting would probably achieve the same goal as this puts the variable resistor on the highest ohms.and hence on the most "backflow" restriction. So no shorting plugs on the tuner and volume control on "Low" while I use the fixed outputs.