I am not an expert on anything related to audio, let alone turntables. Therefore, the goal of this project was not to create best quality audio and high tech output. I wanted to create my own turntable that I think is an interesting design piece. Two main objectives were:
- Vertical position of the vinyl and a clear view of the record itself.
- Ability to play both sides of the record automatically after each other without extra actions.
Step 1: Overview of Design
I started the design of the turntable by drawing some 2D front and side views of the main shape. Since I wanted to display the vinyl vertically and be able to turn it without taking it out, the design hold a rotating function. The vinyl can spin 180 degrees on the vertical axis. I didn't want to use multiple tonearms or a complicated design of it. The concept is that the tonearm moves out of the way to let the vinyl turn. I chose a simple triangle shape to continue the design.
I made a paper 1:1 scale model. This way I could determine the rough measurements. The third image shows this model. The main shape consists of two main parts. The base, which house the controller and buttons and the upper part. This upper part can rotate on a vertical axis and holds the vinyl in its middle. The design is not completely vertical. It angles backwards 5 degrees. This way, the future tonearm can still perform some pressure on the vinyl by gravity.
The next step was to determine what components were needed and what the general layout of the system will be. The third image shows this overview. I used a tonearm from a second hand turntable, a solid AKAI model. Also the DC motor was scavenged from an old turntable.
The overview shows a motor to spin the vinyl, a stepper motor to turn the record around, and some components to control the unit and to help to automate it. The final prototype is not automated yet. I'll have to spend some more time programming with the Arduino IDE. For now the record spins and plays audio, but the tonearm and flipping the record are controlled by hand for now.
Because I used some parts that are ripped from old turntables, this design is not one fits all. If you want to make your own, you got to be able to make your own version of it. Other hardware requires other designs. Being able to create your own CAD files is important.
Step 2: 3D CAD Design
Once I had an idea of the required functions and the hardware, I started designing everything in CAD. Since I wanted to challenge myself, I created a lot of custom parts for my 3D printer. The design is compact and packed with components. It is convenient to model hardware like motors in the assembly to make sure everything fits.
The main challenge for me was to reduce the RPM's from the DC motor to the driving axle. As you can see partly on the second image, I reduced from 2000 to 33,3 RPM by creating two reductions. Lowering the voltage on the motor also helped.
All parts I designed are available in STL format on thingiverse:
For now I will only actively drive the DC motor with an Arduino/motorshield module. A future version of my design will have an automated turning mechanism and automated tonearm. First I wanted the core of the design right before moving to programming different components.
Step 3: 3D Print Parts, Priming, Painting
Since 3D printing with plastic filament does not provide a smooth and nice surface, it is very satisfying to finish the parts that are in plain sight. It requires some effort and patience, but it is worth it.
I sanded my outer parts with grid 120 before getting the woodfiller in. Smooth out the filler, let it dry, sand, prime, sand and do it again. It depends on the finish you are looking for. I sanded the main parts down to 600 grid before applying the final, yellow paint. I used a small roller brush to get a nice finish. Since yellow is a light color, I needed to apply at least 4 layers before it looked good.
Make sure to use water based lacquer if your primer is water based.
Step 4: Overview of Hardware
A. Anti vibration feet made of rubber. *
B. 80mm long 12 mm diameter copper tube. This tube will be used as a vertical axis in the base compartment.
C. 1 bearing, 3 mm bore, 10 mm diameter. 3 bearings, 8 mm bore, 22 mm diameter. m8 nuts and bolts.
D. A sufficient amount of m3 bolts and nuts. Most of them require a short length like 9mm thread.
E. DC motor. A silent motor is a must. This motor runs max 8V with 2000 RPM.*
F. Nema 16 stepper motor. Used to drive the vinyl turning mechanism. Any stepper motor with some descent torque will suffice. The stepper motor is fitted with a GT2 20 tooth pulley to connect it to the GT2 belt.
G. Axle fitted with a spring. This axis came from the center axis of a turntable.*
H. Tonearm assembly. The tonearm I salvaged from an AKAI turntable has a nice curve to it which was required for my design. All the wires are still attached. When the tulips are plugged into an amp, it will generate the sound. The tonearm has a reasonably new cartridge.*
I. Input buttons. To operate the turntable, some buttons come in handy. For my design, I selected two push buttons and one potentiometer for analog input.
J. 280 mm GT2 belt and two elastic belts. These parts are used to drive certain parts. One rubber belt is actually a Lego one. Belts similar like this were often used in tape decks.
K. Arduino fitted with adafruit motorshield V2 and connected to a drv8825 stepper driver.
L. Power supply. I used a 12V power supply that can provide a max of 1.5A. I run my stepper motor at around 1A and the DC motor doesn't use that much power, so this little PSU will do. Make sure to never over-volt your hardware. My DC motor only gets around 6V through the programmed motorshield.
*Part salvaged from various, old turntables.
Step 5: Overview of 3D Printed Parts
A. The base.
B. Side B.
C. Side A. holds the reduction and the DC motor to spin the vinyl.
D. Tonearm axle. The tonearm is hinged to this part to move up and down.
E. Tonearm axle mount. This part connects the tonearm axle to the base. It also allows the tonearm to spin around the axle.
F. Stepper motor mount.
G. Side A vinyl holder. Both side A and side B vinyl holders are fitted with magnets that attract each other. The vinyl record is clamped between these. Side A's holder is the driven one.
H. Side B vinyl holder.
I. Coupler. This part clamps the sides to the base and can turn around its axis.
J. Motor mount. This part shoves over the DC motor to connect it to side A.
K. Big gear. Reduces the RPM's from the motor to the driving axle.
L. Big pulley and the small gear. This is part of the drive reduction. It holds a 22mm diameter bearing to allow it to spin freely.
M. Toothed pulley. This pulley clamps the coupler and the sides to the base by 10 m3 bolt inserts. It is driven by the GT2 belt from the stepper motor. This part can turn the vinyl's side.
N.Side B axle cover. Covers up the axle end on side B.
O. Front knob that connects to the potentiometer.
P. Side A axle cover. Covers up the axle end on side A.
I use a total of 14 neodymium magnets in my design to get parts to stick together. Make sure you get the poles right!! They have to be in the same direction of the horizontal and the vertical axis of the total design. My magnets are 8 x 2 mm in size.
Step 6: Prepare the Base
I started with the base of the vertical turntable. Start with gluing in the magnets. Any plastic modeling glue will be fine. Make sure they the poles are heading in the same direction on the vertical axis.
Secondly, shove all the required m3 nuts in place. These will provide function if we later on install the tonearm.
The stepper motor can be pushed into place and loosely bolted in on the under and upper side of the base.
Place the buttons in the front of the base. My buttons are not yet functioning so I will take them out and solder some wires to them if my design reaches the next stage.
Step 7: Prepare Tonearm
The tonearm is the key component in a turntable. This 'reads' the record which produces sound. Therefore it is important to understand it. The following link provides nice and clear information on how a needle behaves on the vinyl and how to correctly adjust it:
The needle may only apply several grams of force on the vinyl, otherwise both may be damaged. Balancing an almost vertical positioned tonearm is hard, but pay attention to it!! Most tonearms are positioned horizontally. Because my tonearm has a bend, I adjusted the backside of the tonearm to have an angle to provide a better center of mass in the vertical axis.
Step 8: Prepare Side A, the DC Motor Driven Side
Side A drives the vinyl record once it is completed. It is an important assembly and it helps if all the parts have proper dimensions and don't grind on each other.
To start, a proper metal axle must be selected and put into the upper bearing in side A. On this axle a small pulley with the first, smaller rubber belt is placed. Make sure that the band is installed around the pulley before securing the axis into place. This is a part that you have to be creative about yourself with parts that you have. Make sure it runs smoothly with some grease and that the axle runs straight. A wobbling axle may give problems when playing a record.
After that, install the magnets. This time, make sure they want to stick to the base when you place side A on the base.
Fit the m3 nuts and secure the DC motor in place. Depending on your motor, you may want to install some rubbery material between the motor and the side component. This may reduce vibration sounds that the motor might produce.
Bolt the two M8 bolts with their corresponding gears in place. Make sure that the pulley under the big gear grabs and connects with the rubber belt connected to the upper axle. Fit the final belt to the DC motor.
Step 9: Assemble Axis and DC Motor Leads
A straight piece of copper tubing can be used to create a spinning axle in the base. It creates a pivot point for the two connected sides through the gray coupler part. I drilled two holes in the sides to feed the DC motor wires through.
The big, toothed pulley must be placed over the copper tube before running the wires. The GT2 belt fits around the pulley.
It may take some fiddling, but pulling a thin metal wire from the bottom connected to these wires will help.
After everything is in place, the coupler can be loaded with 10 m3 nuts from the top. Don't topple the assembly yet, or they will fall out.
Step 10: Assemble Side B
The assembly of side B is really straightforward. The axis is fitted with a spring that pushes vinyl holder B forward.
Make sure that the inner sides of the magnets attract the opposite vinyl holder A.
Once the axle was secured with a clamp, I glued the back button to the axle (!and the axle only!) with some two component glue that can glue metal to plastic.
Check if the moving parts are running freely and sand and/or grease if necessary.
Step 11: Putting Side B on the Base and Securing Everything
Once both sides are completed, side B can be included in the main assembly.
Tighten the GT2 belt, secure the stepper motor and insert m3 bolts in the bottom of the big pulley. Once these are bolted in the nuts in the coupler part, everything should be held in place firmly, but the sides should be able to rotate around the copper axle axis.
Step 12: Finishing Up Side A
Finish up side A by fitting the vinyl holder. Again, this part holds magnets which poles have to face the same direction. This part does't need to be glued down. It should fit snugly on the driving axle.
Step 13: Prepare Electronics
Since I am still figuring out how to use the Arduino in the best way in this design, I will not go into detail on the components that could be needed. Buttons are still not wired up and there is no feedback loop. This is some work for the near future. However, the only component I use to drive the DC motor is the Adafruit motor shield V2. A very elaborate information page is available on their website:
I also coupled a DRV8825 driver board to the arduino to control the stepper motor. These are ideal to control a stepper in a safe and precise way. One could use the motorshield to control the stepper, but it depends on the current the stepper motor draws. I myself blew up half of the motorshield because my stepper motor drew too much current. Always do research on what your hardware requires and what it is capable of.
Descent information on the stepper driver can be found at:
Step 14: Assemble Final Parts
To finish up, connect some rubber feet to the base. Damping vibrations from the surface of which its standing on can help reduce noise in your audio signal.
Make sure the tonearm can move freely inside of the base and get rid of any unnecessary wiring.
Once you get everything cleaned up, bolt the back part on the base. Feed the power and the audio cables through the bottom or create a new hole if required.
Fit the last parts to cover up any eye sores and your done!
Step 15: Enjoy Your Vinyl in a Fancy Way!
First Prize in the
Audio Contest 2018