Building the Lotus Group Reference Turntable

Joe Cohen

Industry Expert
Jun 10, 2012
220
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Turntable1B.jpg

14 years ago a friend of mine called and asked if I would like to take a class at the Randall Museum in San Francisco where we would be building our own turntables. The museum Director was an audiophile/engineer. I said yes, of course. So over a period of many months we drove into San Francisco together every Saturday morning where we first built our motor controllers and then later the plinths. The museum has a splendid wood shop in the basement. My design differed from the others in that I chose not to have a piece of granite sticking out of the top. I also drilled 15 - 2 inch wide holes in the 4 inch thick plywood plinth and filled them with lead shot. I also had a 1” thick aluminum sub-plinth fabricated. Years earlier I had acquired some musical instrument grade flamed maple which I used to clad the plinth. I also installed the Ebony purfling that’s visible on the top. The plan was to use the original Galibier vinyl platters and bearing which all of the others in the class used, but I was fortunate to be able to make a trade with Peter Clark of Redpoint turntable fame for one each of his glorious platters, motor pods and bearings. So I had all the makings of a great turntable, but life intruded and I found myself ten years down the road with a bunch of parts stored in a closet.

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I finally determined to complete the project. I could no longer stomach the idea that I had started but not completed it. The first thing I had to do was to acquire a 2 5/16" inch socket in order to be able to fix the bearing to the plinth. I placed the plinth assembly on the stereo cabinet, oiled the bearing chamber and dropped the spindle in (very satisfying watching it descend so very slowly - nicely machined!), then I lowered the platter and gave it a spin. Something was not right! I got level with the top of the platter to eyeball it. There was at least a 1/16” runout! I tried calling Peter but he was too ill to help. I called Thom Makris at Galibier but he could not help either. Finally I located a machinist who had the skills to work on a turntable assembly. He re-ground the top of the spindle assembly to a tapered cone and re-machined the inside of the top of the platter to match. Now the platter spun smoothly and was lowered to a more pleasing distance from the top of the plinth.I also had him make the adjustable arm board out of 316 stainless steel. I applied a massive amount of fo.Q TA-102 damping material before connecting the sub-plinth to the plinth. My son assisted me in lining the entire underside of the armboard with TA-102, which was a great idea, but…when I loosened the bolts that hold the board in place to slide it forward to adjust the pivot to spindle distance it would not budge. The pressure of the bolts on the arm board and plinth fastened the TA-102 firmly to the maple top. What was I to do? Any attempt to pry it up with a tool would’ve marred the surface. I finally decided to take a hairdryer to it, and with patience it eventually loosened. I covered the TA-102 with blue masking tape so that it would not stick again. Worked like a charm.

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We had exhibited at a number of shows with Joel Durand and I was quite familiar with his wonderful tonearms. I purchased his Kairos unipivot tonearm and an Ortofon Windfield cartridge. These days I lust after his Tosca gimbal-bearing design arm. What a tour-de-force that is!

Kairos.jpg

tosca.jpeg

Plinth2.jpg

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Finally I had a local cabinet maker build the turntable platform/rack of my design to which I affixed a Sound Mechanics platform that I had lying around from early days. It too is isolated from the rack by TA-102. Stereo Squares made a custom dust cover to keep the cats away.

The table sits on four fo.Q HEM-25 footers.

Rosie2.jpg
 
Last edited:

Ron Resnick

Site Co-Owner, Administrator
Jan 25, 2015
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Beverly Hills, CA
Congratulations, Joe!

What a fun and exciting project!

PS: I, too, love Joel's Tosca!
 
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Fsonicsmith

Well-Known Member
Jun 25, 2015
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Beautiful Joe. Great story. You want to finish up some 10 year old balsa wood radio controlled planes of mine? They talk to me whenever I go down to the basement.
 
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Fsonicsmith

Well-Known Member
Jun 25, 2015
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btw, Per Windfeld must have been one of those kids who constantly had his name misspelled in school, cursed to have it persist through adulthood.
 
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