Here's a bit of super-obscure lathe history....

[Deke Dickerson]

I was looking through a vintage Cinema Engineering catalog from around 1950-1951, and saw this amazing mechanical EQ they used to make to compensate for the high end loss as the groove gets closer to the center.

As near as I can tell, this EQ had a spring connected to a string that actually turned up the high frequencies as the carriage moved in and pulled the string. You'd mount the EQ somewhere on the lathe and set the spring tension, and it would slowly turn up the high end as the carriage got closer to the center. Pretty ingenious "old school" way of accomplishing this, pre-computers, no relays or switches needed.

In the photo, one of these devices is hooked up to what looks like (to me) an Arcturus lathe.

Anybody ever SEEN one of these things?

Also on the same flyer, interesting to note, Cinema also sold the first RIAA-compensated equalizer, also for disc cutting purposes.

Cinema is sort of a footnote in audio history, which is too bad, because they also made the first integrated mixing console, around this same time.

Deke

[piaptk]

Seems like that works very similar to the Presto automatic equalizer. I have one for a PResto 6N if you are interested. Never used it, though...