Quark 125b

[BrianG]

The controller simply sends a set of pulses of audio frequency to the motor in such a way that it won't move. Although, if you don't have the pinion on it, the shaft does move ever so slightly. The tones are made the same way that the "music" is made when running; by the coils vibrating. Some motors are more musical than others. My 10XL makes noise as it is running, but my Neu doesn't - and they both use the same controller. I imagine it matters how tightly the coils are wound...