NOTE : About this switch(MR/250/308) is only a little different :
There are very few differences between the three originals pedals(mxr distorion+,dod250,and JYM308), so only you can find a little difference with a high-powered speaker and adjust the knob In a particular position.
Or When playing a sweep, meaning when playing multiple strings of different frequencies at the same time, you can see the difference between these three switch(MR/250/308)).