My stock Stereomour II was dead quiet with my Klipsch Forte II. Zero hum.
When I installed the shunt regulator a teeny tiny bit of hum appeared. Normal?
It didn't bother me. Not audible from listening distance. My new tubes (Shuguang) seem to make that tiny bit of hum a tiny bit louder. Still effectively unnoticeable at listening distance.
But it would be nice to wipe it out completely, which I assume the DC filament upgrade would do. My question is: is there an additional sonic benefit to the upgrade, or is it only meant to eliminate hum?