Speed Box

The 50 Hz Pro-Ject Speed Box retails for about $59 in Hong Kong versus $99 for a 60Hz model at NeedleDoctor.

1) Has anyone tried to convert a 50Hz Speed Box to a 60Hz Speed Box?

2) Would anyone give me some direction on how to build by own Speed Box (to output a low voltage AC signal with a precise 60Hz frequency)? Or direct me to good kit?

thank you very much,
don burgess