Moving the needle

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The first really cool turntable and arm setup I had ever seen was made by Rabco. The local high-end aficionado, Norm, had a Rabco turntable and attached to it was a strange contraption, a Rabco SL-8 tangential linear tracking tonearm.

Crazy looking thing. I remember when it first was placed into the record’s groove, it would sally back and forth until the servos got hold of the routine and the arm finally got in the groove (to make a pun).

The beauty of a linear tracking tonearm, of course, is the lack of a pivot point and the worry of the needle being at different angles in the groove. You don’t see many today, they’re rather tough to engineer properly.

Lastly, ever wonder what it looks like to be a needle in the groove? Engineer Ben Krasnow wondered as well. He got on his trusty electron microscope and painstakingly made the attached video. Since electron microscopes have to take time to scan the image, they aren’t used to make videos. Krasnow solved that problem with stop-frame motion. He moved the needle and the record 50 microns each time, recorded a frame, then did it again.

An amazing look into vinyl reproduction.

If you are interested in the story behind the making of this film, click here for the backstory. It is even more interesting than the image itself.