Do router speed controls lose torque?

[tbgallant]

Hey guys,

Looking for a straight forward answer:

When using an add-on variable speed control designed for routers with a universal AC/DC brush type motor, does one lose torque?

If so, is it drastic?

Considering picking one up to control the speed of a drill, electric die grinder, small table saw (with brush motor), as well as potentially a bench grinder if indeed those usually use AC/DC brush type motors.

Thanks

Tim