There’s no difference in the circuits. What you’re probably hearing is differences in component values. Potentiometers can have tolerances up to +/-20%. This doesn’t matter much for voltage dividers, but when they are used as variable resistors, that can certainly have an impact.
An option to try is a crude noise gate with series antiparallel diodes and a parallel resistor with a divider to set the loss. You’d of course be introducing crossover distortion, but it may be worth trying.