I just replaced my panaflo with some Scythe SFF21-F 1600 rpm fans but unlike my E fans that undervolt very smoothly my KAZE MASTER controller is like full on or full off with this fan.

my FLEX-E I can adjust 30 rpm at a time with small movements but one small movement on the F and thats it

anyone notice this ???? I just touch the voltage down a 1/8th of a turn and the fan powers off