A DIY (with a lot of help) Turntable
I don’t post new toy write-ups very often, if ever, up until now, so I’m going to throw a whole bunch of new toys into this one post. Blame it on the home isolation. Let me back up a bit. The idea for a DIY turntable began several years ago when I took a DIY phono stage class with Edwin Yang at the Randall Museum in San Francisco. Ed had a DIY turntable. Not knowing what I was getting myself into, I thought it would be fun to build one too. I bought a bearing, and then the clock started running… for about the next five years. The first problem, when given a blank slate to design your turntable is, what do you want to do with it? There are so many possibilities. But I wanted to do something unique, which is almost impossible given the plethora of turntable designs already out there. And, given that I don’t have a machine shop with a metal lathe, I had to find someone to do the work on the aluminum and Delrin for the platter and also the aluminum section of the plinth and the aluminum arm pod. Finding someone willing to do all of this was not as easy as you might think, and took me many months. It is my belief now that most machine shops prefer to make one-part multiple times (the more multiples the better) rather than make one-off individual parts.My original design was for a large rectangular plinth big enough so I could fit two tonearms. Somewhere along the line I changed my mind on that and decided on the curved left edge. Then I decided to move the bearing mount closer to the curved edge so that the edge of the platter would be closer to the pulley which would reduce the belt length. Then I decided to shave the top of the platter to increase the diameter of the top. I’d originally gone with a small diameter based upon the size of the top of my Oracle Delphi MKV platter. So, with each change in specifications came increased delays. And, did I mention that the machinist I’d located had health and family problems? These problems resulted in long, sometimes very long, delays on the completion of my individual pieces? Eventually, the turntable parts were ready for my assembly and I was spinning records on it. But I wasn’t totally happy. The original Ebony that was used to sandwich the aluminum of the plinth cracked within a short period of time, as I was warned it would, resulting in loss of structural support. The optical loop feedback speed control, based upon an open DIY forum design, never worked perfectly either. It all sounded pretty good, but it should have sounded great. So, I decided to replace the DC motor with an AC motor (requiring that a new motor pod top had to be machined, along with a specially sized pulley for the belt) and while I was doing that, I decided I would redo the plinth with Baltic Birch plywood and increase the thickness while I was at it. I also changed the metal pipe motor pod for an aluminum motor pod that would match the arm pod. A friend in San Francisco machined it for me. Thank you, William Berndt. Also bothersome with the original design was the narrow gap between the arm pod and the edge of the oversized platter. The solution was getting a longer arm. I absolutely loved the 9” Tri-Planar MK vii that I had on the table, but getting a new 12” Tri-Planar was out of reach for my budget, so I went with the 10.5” Reed 3P. The 10.5” arm is a nice compromise between the 9” arms and the 12” arms and I think it sounds great in this setup. And, a new arm happened to coincide with getting a new Ortofon A95 cartridge. It’s pretty sublime.
Oh, and then while I was making the new Baltic Birch top, but after having it painted, I had the idea of sprucing up the black and silver color scheme with some LED lighting. I routed a groove below the tabletop level and fixed the lights in there and drilled internal holes in the plinth and ran some wire to the plug I mounted on the bottom in the back. I think it adds a nice touch, especially at night. Once everything was up and running, I became a little disappointed with the feet that I’d chosen. They were nice custom audiophile feet with little points on the bottom to drain energy into the cupped bases, but I think the 100+ pounds of the turntable overwhelmed their effectiveness. So, I considered an isolation platform of some kind, but having the outboard motor pod complicates things, so when I noticed the
Pneuance Audio Pneupod Pneumatic Isolation Feet and read the reviews about what a great job they do isolating components I decided to give them a try. Of course, nothing has really been easy with this project. I ended up needing some adaptors for the ¼” x 20 threaded rods that came with the Pneupods to fit into the M12 x 1.75 threaded receptacles I had mounted in the base of the plinth. There’s a whole story that goes along with this and just about every other component in this piece, but I’ll spare you- and just say that eventually, it all came together.One thing about the table you cannot see is that the bottom of the 65-pound platter has a ceramic disc magnet fixed in place that rappels against another ceramic disc magnet fixed to the top portion of the aluminum section of the plinth. This reduces the weight on the bearing to a little under 10 pounds.At this point, I’m just waiting to find someplace to order an aluminum script logo so I can put the name of the turntable on the front of the plinth. So, it’s not 1000% done yet- but it’s done enough that I am spinning lots of vinyl on it and loving the way it sounds. Was it worth the wait? I’ll just say, I’m glad it’s 999% done.
