Adjusting the Speed

Now I want to get the speed of the playback calibrated.  The recreations (discs) should be played at 80 rotations per minute (RPM).  There are a lot of incorrect references to 78 RPMs on Ebay listings for Edison Diamond Discs.  80 RPM is correct.

The original Edison Instructions mention a special calibration disc and a pitch pipe to make the adjustment.  An alternative is using a stop watch and simply counting the revolutions.

The method I use is the "Stobelight" app on my iphone.  It is free.

Simply place a recreation on the A100, making sure it is properly cranked.  Then in a dark room set the Strobelight app to 80RPM.  Start the disc spinning and look at the label.  If the label stays stationary   with the strobe, you are set at 80RPM.  If it rotates with the strobe, rotate the knob located at the 10 o'clock disc position slightly to increase or decrease the speed.  Once the label becomes stationary the adjustment is complete.

That's it!