It’s April 2020, and after 1 year of hard work I have finished building a new mastering lathe for my studio Sky Onion. I acquired the Scully lathe body, sled, turntable motor, and vacuum platter in March 2019. That was a good set of parts to start building with. The Scully is very old – serial number 22, likely from the 1930’s. I slowly put this together using various parts from anywhere I could get them.
The cutter head is a Neumann SX74 which I was lucky to buy. It’s from the legendary Frankford/Wayne Mastering Studio. I had to design and build the cutter head suspension since I wasn’t able to locate a Neumann suspension for sale. The suspension is mostly off-the shelf parts. I had the big cuts, holes, etc. done by a local machine shop, and I did the small detail work. The chip pick-up tube for the cutter head was missing, so I made one out of a thin brass tube using a blow torch and pliers. It’s not pretty but it gets the job done.
The cutting rack is custom, based on Wayne Kirkwood’s Phono Transfer System. The preamp from Wayne handles the inverse RIAA and feedback mixing. The power amp stage is a Parasound A21 which has tons of power, and it’s also is biased well into class-A at small signal levels. It sounds great.
Variable pitch and depth are handled by Flo Kaufmann & Ivo Studer’s Pitch18 computer. That computer drives a high-quality Swiss DC motor which turns the feedscrew. The motor mount is made of a door hinge and spring tensioner that dissipates any vibrations. Cutter depth is driven by a modified 3″ speaker located inside the custom cutter suspension. Somehow it actually works well.
My good friend Dalton Paull made the table top for me out of a Portland walnut tree. He also found the original ad for the Scully parts on craigslist and tipped me off to them, which is how this whole crazy project got started.
The turntable motor is a Lyrec SM8, the same motor that was commonly used for Neumann VMS lathes. For the thrust bearing I used a simple industrial ball bearing which works well and doesn’t cause any noise issues. I don’t know the origins of the vacuum platter – it was with the Scully parts when I acquired them, but it was clearly made for something other than a recording lathe. I had the spindle made at the machine shop. They also couterbore cut the vacuum platter to fit on the old Scully wax platter. Runout has been eliminated by adjusting a few bolts that compress a neoprene gasket in between the two platters. The whole assembly is now well over 40 pounds, which is heavy enough that there is no noticeable cogging from the Lyrec motor.