In May of 2006 I thought it might be fun to try and build, rather than buy, a turntable. The concept was as follows; Triangular plinth to accommodate 3 arms, each designed along different mechanical principles. Suspension, Pointed rather than sprung, with mechanical grounding of all components via large brass tiptoes. A platter using vacuum hold down rather than a center weight and ring clamp. Belt drive via 3 multi motor pods. Use of an epoxy/ lead matrix, where ever possible, to help dampen resonances. Implementation of an anti vibration device such as produced by Halcyonics, Vibraplane or Minus K Technologies. Last of all, build a dedicated, welded, tubular steel stand that would be filled with a lead shot / elastomeric material to reduce resonances. This stand would house the table, 3 electronic motor speed controllers, 3 phono head amps for 3 moving coil cartridges, and a high quality stereo pre amp to act as a switching device among the 3 cartridges. The pre amp would need balanced outputs so that I could locate the table anywhere within the listening room. The table is about 2 months from completion. The above photo, taken just before Christmas, shows most, but not all the design elements in place. This photo essay, along with brief descriptions of each step, may be of interest to anyone who ever deliberated the merits of the various table designs out there before making a final choice.
DIY MK 1 Plinth Pattern
Since the triangular pedestal is the heart of the table, a pattern will be required in order to laminate the fiberglass mold into which the epoxy matrix will be poured. Shown is the MDF sheets being glued together from which the pattern will be fabricated. The dimensional stability and easy machinability of MDF makes this the material of choice. Note the table bearing well machined into the top 3 layers of MDF prior to gluing up step. The well side walls are tapered with a 3 % angle in order to facilitate demolding of the final part from the fiberglass mold.
DIY MK 1 Pattern Cut
The pattern shown includes 3
DIY MK 1 Texture Added
The accurate final assembly of the pods to the center pattern is accomplished by using biscuit joints and polyurethane glue. The black panels shown are the surfaces that have been laminated with slate textured, high pressure laminate.The remaining surfaces will be high gloss black. The contrast will not only be more attractive, but offer a more dimensional surface on which to mount the arms and levelers
DIY MK 1 Pattern Glue Up
Assembly of the 4 pattern pieces requires tight, accurate clamping. The irregular shape means typical clamps may not fit the bill. A band clamp on the bottom and pinch dogs on the top keep the parts from shifting when the pressure is applied.
DIY MK 1 Pattern Coating Applied
After the clamps are removed, a decorative chamfer is machined around the top perimeter of the pattern. After the slate surfaces are masked, the pattern is sprayed with a polyester pattern coating. When the coating cures, the pattern can be sanded and polished prior to the production of the fiberglass mold.
DIY MK 1 Lets Start Building A Mold
The finished pattern is mounted to a mold plate, prepared with multiple coats of mold release wax, then sprayed with a poly vinyl alcohol film forming barrier coat. The dry PVA film can be compared to sheet of saran wrap that will prevent any bond between the pattern an the mold surface about to be applied over the pattern.
DIY MK 1 Surface Coat Applied First
Shown is the application of the metal filled surface being sprayed over the pattern. The surface coat will generate a mirror of surface of the pattern that will become the performance surface of the production mold. This surface coat is a 2 part, catalyzed material, as compared to an air dry, solvent based paint. Once cured, it will be impervious to the chemical attack generated when the final production pedestal is cast.
DIY MK 1 Fiberglass Comes Next
Laminating fiberglass re-enforcemint will add strength and bulk to the thin layer of surface coat that has been sprayed over the pattern. Multiple layers, that add up to 1/4 inch in thickness, will be required before we can proceed to the next step. The dark areas around the corners and edges come from the paste made from ground glass, calcium carbonate and cotton flock that was brushed on prior to the first layer of fiberglass. It will eliminate any small air pockets that may result from the difficulty in getting stiff glass fibers to conform to sharp inside and outside corners.
DIY MK 1 Rigidize The Laminate
Even though a 1'4 inch laminate of fiberglass has a great degree of strength, it must have a substrate of some thickness to maintain rigidity and dimensional stability. Panels of MDF are bonded to the flat surfaces in order to accomplish the desired result. Another layer of fiberglass will go over the MDF panels to effect a sandwich type of construction that will guarantee dimensional stability for years to come. A box will then be bonded to the back of the laminate to facilitate easy handling.
DIY MK 1 Showtime!
It's time to demold the pattern from the fiberglass mold. Shown at the top of the picture is the light gray pattern, with the darker gray fiberglass mold in the lower part of the picture.
DIY MK 1 Making The Plinth
A few days later the mold has been sanded, polished and waxed. It's now ready to produce a final part. It will take some engineering to determine the size and shape of the aluminum plinth, along with the arm boards needed to accommodate the various tone arms and leveling vials. Because of these factors, it would be a good idea to laminate a trial horse off the mold to be used for experimentation. This photo shows the trial lamination, in black at the right, being demolded from the production mold,at the left, in light gray. This part is just a 1/4 inch thick fiberglass shell without any additional re-enforcement.
DIY MK 1 Trim Out Time
Trimming out a fiberglass part is never a fun job, but it doesn't take that long and it only itches for a little while.
DIY MK 1 The Finished Plinth
With 2000 grit sandpaper and a little polishing , and it's as shiny as new money.
DIY MK 1 Plinth Plate
A mock up of the aluminum plinth plate, done in MDF makes it easy and inexpensive to work out the details before machining it in Aluminum.
DIY MK 1 Plinth Plate Mock Up
Angles and measurements are accurately transferred to the MDF pattern, then cut to size.
DIY MK 1 Progress Check.
With the vacuum platter on top, and the plinth plate on the bottom, things are taking shape. A few changes are made on the thickness and overall dimensions of the plinth plate, in order to maintain good proportions, and it's time for the next step.
DIY MK 1 Tip Toe Check
Tip toes are mocked up in steel. Final parts to be in brass, but a thinner jam nut in brass is a must.
Dynavector DV 507 MK 11
A Dynavector DV 507 MK II is shown ,sans head shell and counter weight, positioned on the first of three pods that each will accept a different type of tone arm.
Kuzma Air Line
The Kuzma Air Line, to be mounted at the rear of the pedestal, will make an impressive contribution, not only to the performance but to the overall looks of the project.
Tri Plainer Mk V11
My intention in choosing arms was to utilize 3 very different arm types.The Tri Plainer Mk VII, mounted on the third pod of the table, will complement the other 2 choices.
VPI Industries HRX Drive
The drive unit of choice is the VPI HRX twin motor drive. Utilizing a 15 lb stainless steel flywheel, the added mass will go a long way to maximize the speed stability of the table.
VPI Industries SDS Controller
The VPI SDS electronic controller was the natural choice for the HRX motor drive. 3 separate SDS controllers will power the 3 HRX motor drive units powering the platter.
DIY MK 1 Final Dimension Check
Shown is the pedestal with the plinth, platter and all 3 arms positioned correctly with respect to
DIY MK 1 CNC Time
The dimensions and angles of the mdf mock up of the plinth plate are transferred to a CNC machining center where the a 1- 1/2 inch thick aluminum slab is cut to the same dimensions, and the 1-1/2 fine threads are tapped to accept the tip toes.
DIY MK 1 Arm boards next
A 3/4 inch thick aluminum arm board will be used to mount the various arms to the top of the pedestal. Note the inset vial level that will be used to continuously monitor the levelness of the table. A mock up tells me if my dimensions are correct before I proceed in aluminum.
DIY MK 1 Aluminum Arm Board
The arm boards have been cut from 3/4 inch aluminum and the underside cored out removing almost 50 % of the aluminum. This cored area will then be filled in with a lead shot/ urethane elastomeric matrix that will dampen the resonance that might occur in a solid aluminum arm board.
DIY MK 1 Final Machining- Arm Board
Additional machining on the top side includes a hole to access the top of the tip toe. Here a long T handle allen wrench can be inserted, fitting into the top of the tip toe, for easy adjustment of the pedestal height.
DIY MK 1 Arm Boards, Final Location
Accurate location of the 4 mounting holes for the arm boards in the top of the plinth are laid out, along with the other holes for the arm cables, tip toe adjustment holes etc.
DIY MK 1 Secondary Fittings Installed
Aluminum bars to accept the 10-32 threads for mounting of the arm boards , along with various pvc fittings to act as conduits for arm cables and tip toe adjustment, are epoxied in place.
DIY MK 1 Aluminum Motor Bases
2 inch thick aluminum billet has been machined out to act as a bases for each of the 3 drive units. The drive units will be firmly bolted to these bases with a thin sheet of Isodamp in between for good contact. The chamfered edge has been maintained for continuity of the overall appearance of the unit.
DIY MK 1 Motor Bases- Underside
As with the aluminum arm boards, the underside of the motor bases has been heavily cored out. This will then be filled with the same lead/ elastomeric matrix as used in the arm board. 3 holes are visible for the 1-1/2 dia threaded tip toes that will level and mechanically ground each motor drive unit.
DIY MK 1 Threads And Holes
Threads for mounting the arm boards are tapped into the pedestal prior to it being filled with an epoxy / lead matrix. The holes for the signal cables and tip toe access are also drilled.
DIY MK 1 Final Plinth Polishing
Final 2000 grit sanding and polishing of the plinth is done now. The next step will be to cast approximately 240 lbs of lead and epoxy fill into the underside. After that step it will be too heavy to handle for anything other than the final mounting on the aluminum plinth.
The picture of your beautiful assembled behemoth reminds me of an aerial shoot of the Zeppelin Ludwig kit of John Bonham's. I realize some pissy audio- snobs may shrug off this remark but, well fine... I would love to hear the driving force of this transcriber plowing through the grooves of the classic Lp Led Zeppelin I, no doubt, it would do the both justice! ;^)
Kftool, Beautiful table, it looks like a true labor of love by a skilled craftsmen. Thank you for showing all of us an outstanding industrial design and build process, this is a fantastic insight you have shared into what our hobby is really all about and a great influence for future builders. I have an automotive industrial design background that really offers a great appreciation for your choice of materials, constrained mass construction, and three arm flexibility, smart concepts. Also with this crazy amount of mass in motion from a belt driven/flywheel affair, I'm sure it will play with gusto and dead quiet backgrounds. Bravo!
Hello there, It seems that any compliment that i can give you has already been said and right so! All i could do now is sit back and wonder how the human imagination is so powerful and they say we only use 10% of our brain! You sure proved them wrong!!!!! beautiful art piece....
Fritz the cat, I think it's wonderful that you plan on bringing that table to my house in your 1955 Chevy, I can hardly wait for us to listen together.
It is truuly a piece of great art the turntable that you created. I wish I had the knowhow, patience, skills and recourses to pull of a masterpiece like that.
My knowledge of arms is very limited, my VPI Scout is my 2nd turntable I own. But I might have chosen different arms then you have. Maybe a Schröder and a SME.
I favor the desigh of the Kuzma Air Line and have a My Sonic Labs Eminent for one Air Line and a Koetsu Platinum Signature Jade for the other Air Line. The Dynavedtor DV 507 Mk II will be fitted with both XV 1s stereo and mono cartridges via plug in head shells. I've yet to hear any of the arms or cartridges as all are still in boxes, but based on what I've read, I'm looking forward to the sound of the Koetsu - Air Line combo, especially on classical music.
The project began almost three years ago and has gone through a few changes. I hope to have it up and running by Christmas. I replaced the Tri Plainer with a second Kuzma Air line, both are still in the box as the table has yet to be assembled but all the parts are finished.
Two months ago I decided to increase the mass of the platter. I looked into a one inch lead slab I could machine and bond between the sub platter and the vacuum disc. Lead that thick is hard to find and is available only as dead soft lead which is hard to machine. The price I got was exorbitant so I looked into casting a platter.
I found a company that casts lead with 3% Antimony that increases the hardness of lead and makes machining easier.
I welded up a metal mold and sent it out to be poured with 80 lbs of lead. It's been machined and sent off to be bonded between the sub platter and vacuum disc and sealed with an epoxy coating. I hope to have it back soon so I can begin the assembly ot the table.
Since I increased the height of the platter by one inch it was necessary to raise the three armboards up with one inch brass risers.
Hopefully, there will be no more changes that will delay the compleation of the project.
There are always technical professionals that design breakthrough products that utilize state of the art thinking. However, at the same time there are those who have a level of passion that they too, come up with breath taking products. The audio community has a balanced mix of both. The final judgement of their efforts is always determined by their bank accounts. If enough of us realize the fruits of their efforts by opening our checkbooks and buy their ideas, we can perpetuate their drive to produce new and upgraded products. If the creek don't rise, they can be a success.
This TT is but a collection of tried and true axioms in design, built by a person who would rather spend any amount of money to validate an idea rather than buy the best out there that someone else built. How it will sound is about to be evaluated. While I'll be playing records on it for the first time, I'll be thinking of the next project. The saying, " The journey is more fun than the destination," certainly applies to me.
It sounds as though you may have an inkling to follow a similar path.
My company builds polyester tooling for the cast polymer industry, so I've had what I needed to convert my ideas on the TT project to reality. How it will sound is yet to be determined.
It has been 2 years, almost to the month, since I started the project. All the parts are here and are waiting to be assembled. I can't believe how many times I've changed one thing or another. It all translated to a delay in time and an increase in cost. Now I know why high end TTs cost what they do.
If you can be a bit more specific on what your question is regarding the mix for the molds, I'll be happy to help if I can.
I thank you for your response and comment on the project. It's become one of those things that keeps growing in scope. Whenever I find another avenue to explore I take it, especially if I feel that it will it will affirm the thoughts behind my TT project.
A while back, "Grooves" posted regarding the use of an accelerometer to measure the vibrations inherent in turntables and stands. It sounded as though it was the logical way to eliminate Subjective opinions as to how vibrations affect the way a TT / stand sounds. Thanks to Grooves I'll measure what is going on as I assemble and fine tune the TT as I assemble it.
Listening to music is the end result of our hobby, but putting our own personal tweak on the gear is what keeps us happy to hear the music better than everyone else.<>*^
You and Yildiray must have been on the same wavelength. Your reply gives me an opportunity to express a view that might seem contradictory to the projects I've undertaken and posted on Audiogon.
There are many turntables that use inverted bearings. I may be wrong, but I know of only SOTA that implimented that design 20 years or so ago. If you assume all inverted bearings do a good enough job to SELL, the difference among them could be ; motors, drive belt, isolation, sprung or pointed design, one or four beers, etc.
I dare say that if I took the table bearing from 20 year old SOTA STAR, replaced the bearing and saphire bearing plate, I'm not sure I could hear the difference between it and the new SOTS stuff I'm using. I'd like to think I would, but, if my life depended on the decision ??? Boy , I just opened myself up for criticism.
I shall make a comparison of audiophiles at both ends of the spectrum. --- EXCUSE ME ALBERT. At one end of the spectrum, you have a person that educated his ears to what sound best, over many years. It takes time, discreation, good judgement, money and a patient wife-- partner.
After many decades, he knows what sounds right to him and, with an open mind, will listen to the other side. Now let's go to the other extreme.
About the same age as Albert, a few years older, an audiophile always who wanted the best, but traveled a different road. My business didn't include audio so I needed to learn on my off time and never had much. The mantra of "Bigger Is Better" hopefully offsets the lack of experience that comes with time. If it costs more, weighs more, looks better, sells better, is written up more--- it must be good, maybe not.
When you have less time to hear for yourself, you make educated, or uneducated choices. That's me. I have no reason to think I'll hate the sound I'll hear. After all , it's the fruit of my labors.
The only rules that apply to what your choices are can be summed up -- you're the only one that counts.
"Enjoy The Music." Raul, you should've copywrighted the phrase.
Thanks for the response and kind words. In answer to your questions---
My original intention was to use a 1 1'4 inch thick platter of 304 non magnetic stainless steel. I still have the 13 inch square slab I bought almost 18 months ago when I started the project. 3 motor drive pods, each containing 3 Hurst 300 rpm PA motors, driving a 10 lb stainless steel flywheel. I still have the 9 Hurst motors I bought, now unused, just sitting on a shelf. If anyone needs them, let me know.
A long time friend of mine owned a top shelf machine shop with cnc machines capable of turning the platter and flywheels. One day he just up and sold his company to a bean counter with money and no skill or ability to run a shop, my plans had to change.
20 years ago I purchased a SOTA Star- vacuum from Robert Becker at a CES show. Just 2 years ago I bought a Sota Millennia from Kirk and Donna Bodinet at the 2005 CES, it is still in the boxes, unused. I always enjoyed the performance of the Sota tables, so the choice was an easy one. The Bodinets sent me the platter, inverted bearing, and vacuum system as supplied on my Millennia. Since I had a stainless slab for a platter, I asked if they could have their machinist make one for me and if their inverted bearing would handle the 75 lb platter weight. David Fletcher, the designer of the original Sota table design still consults for SOTA, so after checking with him, I was told the bearing would properly handle a platter weight up to 100 lbs. I would have to wait for another batch of platters to be run before I could get one. That was about 14 months ago. I was sure this project would be done in about 6 months, so I bought the standard SOTA platter.
It will be only another few months when an order for another batch of platters will be placed. I'll get my stainless slab machined then and have an extra new platter on the shelf.
Regarding the motor drives; The VPI Hrx drive uses 2 Hurst - 300 rpm - PA motors and a 15 lb stainless flywheel, I was rescued!! I ordered 3 HRX drives and 3 SDS controllers for a lot less than the cost of maching my original motor drives. I plan on using 20 # test, WOVEN Spyder wire, for the 3 drive belts, a suggestion from Harry at VPI. Durring the discussion, I asked what would happen when the knot came around, "nothing" was his reply. I asked why he didn't use Spyder Wire if it was superior to a rubber drive belt. His reply," I be spending too much time on the phone answering the same question you asked, it's not worth it." The only change I'm making regarding the HRX drives is cosmetic. I've stripped off the wrinkle coat paint with Methylene Chloride and will be sending them to Rayco Industries and Valley Plating in Conn. to be brushed and anodized in Krell Gray hard coat and black to match my Krell gear.
In keeping with the idea of three's, three arms will give me the opportunity to use 4 top cartridges simoutaneously. The Dynavector DV 507 MK II , with an extra plug in head shell, will enable me to switch between Dynavector XV-Is stereo and mono cartridges, as I have enough great mono classical titles to make it worth while to have both.
My original choice of arms included the DV 507 MK II, the Tri Plainer VII, and the Kuzma Air Line. A few months ago I felt another Air Line would be a better choice than the Tri Plainer, a great arm in it's own right. The "gonner" that bought it got a new and unused arm at a great price, praise the Lord for Audiogon.
I have another 550 lbs of aluminum almost ready to ship off to Conn. and I need to take and post pictures on Audiogon. My friends in audio keep asking me how I can be so patient with this project. Long term goals are the best, and WORTH waiting for.
I have a Koetsu Platinum signature Jade, My Sonic Labs Eminent, and a Shelter 90 X. I bought the shelter 2 years ago , almost to the day, and finally installed it 3 weeks ago, I'm listening to it now, instead of the Benz Glider. What a difference. While I bought the cartridge new, I'm not the first person to listen to it.
6 months or so ago , I responded to a thread, probably on the analog site. As happens , the discussion wandered off on a tangent. I posted a thought about getting something for nothing, made mention of some members of society getting legal representation free, a metaphor of great sound cheap, if I remember correctly. If I'm wrong, I'll defer to Hillary's, " I really don't recall." I was posting to a reply from "gregadd." Look up his thread responses if you have time. He, as a lawyer, seems to have chosen to have a great social conscience, rather than a big bank account; The legal shark community could take a lesson from Gregg. In an attempt to ease my conscience, and as a remedy for "foot in mouth disease," I sent my 90 X off for him to try --- a true gentleman.
Music is great, along with the "gonners" that have the same passion.
Ken, You mentioned you will be using a vacuum platter for this project, can you tell me where you sourced the platter, is it from a donor table or have you managed to get your hands on one from a table manufacturer.
