I have been reading about the “benefits” of lowering input voltage for vintage amps like the 5E3. I can see using one on a vintage amp that was designed around 110V input. My question is about modern transformers in current 5E3 clones. I have a 5E3 clone with a Mercury Magnetics FTDP-MM power transformer with a spec of 335-0-335 unloaded with an input voltage of 120V. Is there any benefit to using a voltage regulator/variac to lower the input voltage on an amp like this? Or would lowering the heater voltage in the process be undesirable? My wall voltage is about 120V to 121.3V depending on the outlet I am measuring.