Traditionally, speed testing of turntables has been done by viewing a series of bands on the turntable platter under mains lighting. The frequency of the mains supply (50Hz in Europe / 60Hz in the US) causes the bands to appear stationary at the desired speed and adjustment can be made using the turntables speed controller (if fitted).
Unfortunately mains frequency drifts over time making conventional speed measurement inaccurate. To overcome this problem, companies such as KAB and Clearaudio have produced quartz locked illuminators which work independently of the mains supply to give highly accurate speed readings.
While useful, these strobes are rather costly for the average user who only checks speed accuracy on occasion. The DIY Turntable Strobe is a cost effective alternative to commercial designs and can be built for just a few dollars.
DIY Turntable Strobe © D Tilch -Jhb, South Africa. Feb 2006
Strobe Project PCB Artwork (Hewlett-Packard PCL-3 format)
Discuss the DIY strobe in the Forum