DIY Turntable - Hi-Fi Phono Record Player

DIY Hi-Fi Phono Turntable Project

This DIY turntable project was completed by Nandor Szabo, a very talented DIYer who is located in Hungary. His English is far better than my Hungarian and I agreed to assist in presenting his DIY record player project for him. I had no part in this project and am acting only like an editor. - Bruce Heran. Additional edits and commentary by Giovanni Militano

Photograph 1: DIY Hi-Fi Phono Turntable

This DIY record player project started out as a need for a turntable. I acquired a Dual 701 direct drive turntable which was used as the starting point for this DIY turntable project. Since I had already located a good motor and turntable platter assembly I set out to construct a turntable base (plinth) and a DIY tonearm for the record player. The general construction sequence for the DIY turntable project is outlined in the photographs and build log that follow.

The choice of a Dual 701 turntable as a starting point for the project is a good one as the motor is a DC servo controlled unit that in turntable terms is known as a direct drive type. This means the motor is actually part of the rotating turntable assembly. This is unlike both idler wheel and pulley belt drive type turntables which are more common. The discussion of the relative merits of each type of turntable drive is up to the end user and will not be part of this project. The advantage though in using the direct drive unit from a Dual 701 turntable is that it is a rather vibration and noise free assembly and that it can be directly mounted to the same board as the tonearm. This is in fact how the original turntables are constructed. Mounting to the same board simplifies the construction process considerably. The Dual 701 turntables were manufactured between 1973-76 and a typical Dual 701 turntable is shown in Photograph 2. Only the platter and the direct drive motor assembly with controls was used from the Dual 701 record player.

Photograph 2: Vintage Dual 701 Direct Drive Turntable

The tonearm is a very special design that has been built by hand using local materials and the assistance of a local machine shop. The DIY tonearm I used for this project is unlike most tonearms in that there are no fixed pivot points or bearings. The tonearm tube and counterweights are suspended on a monofilament thread and held in place by high strength magnets. This tonearm design has very low friction.

DIY Turntable Plinth (Base) Construction

The idea to use a solid plinth constructed of several layers of plywood came from soundfountain.com which outlined the construction of a plinth for the SP 10-Mk2. Since the Technics SP-10 turntable also uses a direct drive motor system I decided to adopt the same design philosophy for my plinth. The base of the turntable will be constructed by stacking the three cut plywood pieces. Plywood is a good material to use for the turntable plinth because it is stable (will not shrink), and relative to solid wood it is less likely to resonate, stronger and weighs less. Photographs 4 and 5 show the paper templates used to cut the plywood sections that will be used for the turntable plinth (base) construction.

Photograph 3: Stacked Plywood Plinth for a Technics SP-10 Turntable

Photograph 4: Plywood Patterns for DIY Turntable Plinth

Photograph 5: Cutting Plywood for DIY Turntable Plinth

Drilling holes through the plywood laminations that will be used to secure the stacked plywood plinth base together.

Photograph 6: Plywood Laminations for Turnable Plinth (base)

Photographs 7 and 8 show the three bolts arrangement that is used to secure the plywood laminations that will make up the plinth of the turntable. The three bolts are approximately equally spaced. The bolts are used to hold the plywood laminations together while the base is sanded. In the final plinth construction the stacked plywood base will also be held together using a wood adhesive (Photo 10). Note that the photographs shown are after the plywood base had already been sanded and stained.

Photograph 7: Stacked Plywood Turntable Plinth

Photograph 8: Stacked Plywood Turntable Plinth

The type of wood sander (belt sander) used to make a smooth round edge of the turntable plinth is shown in Photograph 9.

Photograph 9: Belt Sander used to Smooth out Stacked Plywood Base

A wood adhesive is used to hold the finished plywood laminations that will make up the plinth of the turntable. Staining of the stacked plywood base was completed after the wood glue had set.

Photograph 10: Wood Glue / Adhesive used for the Stacked Plywood Plinth

DIY Turntable Support Feet and Suspension

The construction method for making the circular slots to hold the turntable mounting support feet is shown in Photographs 11 to 13. First a hole saw is used to cut a circular slot that will neatly hold the external hardware of the turntable support feet.

Photograph 11: Circular Mounting for Turntable Support Feet

Once the circular slot has been cut as above, next drill the center hole that will be used to house the adjustable suspension of the turntable mounting support feet. You can use a large drill bit to drill the hole or you can use a small Forstner bit like I did (Photograph 12).

Photograph 12: Forstner Bit used to make Center Hole for Turntable Mounting Support Feet

Photograph 13 shows a bottom view of the center hole where the mounting support will go through.

Photograph 13: Bottom View - Hole for Turntable Mounting Support Foot

The assembly of the support feet for the turntable is shown in Photographs 14 through 21. A photo of one of the adjustable turntable support feet is shown below in Photograph 14 and the mounting hardware is shown in Photograph 15.

Photograph 14: Adjustable Turntable Support Foot

Photograph 15: Mounting Hardware for Adjustable Turntable Support Feet

The mounting hardware for the support feet is firmly secured to the turntable plinth (Photograph 16).

Photograph 16: Assembly of Mounting Hardware for Support Feet

The support feet I used are meant to be hidden inside an enclosure and therefore did not come with a decorative cover to hide the hardware. To make the turntable presentable for Hi-Fi use it was necessary to hide the suspension mounting hardware. You can surely purchase a fancy cover to hide the hardware and dress up the turntable. I went the DIY route and made my own cover for the mounting hardware. To make the aluminum covers I used empty containers of mousse (hair styling product) which I cut to size. These hair products are typically pressurized so be sure they are empty and that you have safely depressurized the canister before you begin cutting. The paint on the mousse tube was removed using fine sand paper which makes the covers look like brushed aluminum. It is easier to sand off the paint while can is intact.

Photograph 17: Mounting Feet Cover made from a Mousse Canister

To hold the cover in place I used a a couple of O-rings - one just smaller than the diameter of the cover and one just slightly larger. The smaller O-ring is placed inside of the circular slot. The cover for the feet is pressed over the inner O-ring and then the larger O-ring is used on the outside to close off the gap and create a friction fit.

Photograph 18: O-ring used for Mounting the Turntable Suspension

Photograph 19: O-ring in place inside the Mounting for Turntable Suspension

Photograph 20: Adjusting the Turntable Suspension

Photograph 21 shows the completed turntable feet with the decorative aluminum cover in place to hide the turntable suspension and mounting hardware.

Photograph 21: Completed Turntable Feet / Turntable Suspension

Turntable Motor and Drive Assembly

Chances are that the turntable motor and drive assembly you have selected to use will need to be custom fit into the base you just built. To carve out the base to hold the turntable motor and for the stroboscope RPM speed indicator (Photograph 22) I again used Forstner bits which have proven to be very useful for this project.

Photograph 22: Forstner Bit used for Turntable Motor Mounting and Strobe Speed Indicator

The Dual 701 turntable motor and drive assembly is shown in Photograph 23. The Dual 701 motor and drive assembly is 3-speed (33-1/3, 45 or 78 RPM) and uses an electronically servo driven system with pitch control. The control circuitry is contained in the base of the motor. I built a separate matching external speed control box to contain the turntable controls. The separate control box contains the power switch, a turntable speed control selector (33, 45 or 78 RPM) and also the pitch control which allows fine adjustment of the turntable speed.

Photograph 23: Dual 701 Turntable Motor with External Speed Control Box

The bottom view of the Dual 701 platter is shown in Photograph 24 shows the stroboscope markings. The stroboscope markings are used with the visual speed assembly which allows you verify or fine adjust the speed of the turntable.

Photograph 24: Dual 701 Turntable Platter showing Stroboscope Markings

Now you can really see the DIY turntable starting to take form. Photograph 25 shows the completed turntable base, with the speed control box to the right and the record platter at the back.

Photograph 25: DIY Turntable with Speed Control Box and Record Platter

Photograph 26: Dual 701 Stroboscope Turntable Speed Indicator

DIY Record Clamp / Turntable Weight

To most a Hi-Fi record player would not be complete without some sort of record clamp or a turntable weight. The idea behind a record weight or clamp is that it will hold the record securely on the turntable platter during playback. There are a number of good record clamps and weights that you can purchase for use with your turntable project. For a turntable record weight I decided to build my own. I started out with a circular door stop. For your turntable weight make sure that you use a non-ferrous metal as we don't want to affect the phono cartridge which is magnetic. You will also want to choose a weight that is perfectly symmetrical. It will be very important that you accurately locate the center of the record weight for drilling the center hole to slide over the record player spindle. If the turntable weight is too heavy or off-balance this may result in excessive wear on the bearing.

Photograph 27: Circular Door Stop to be used for Record Weight

Here is a photograph of the door stop after it has been disassembled. For my record weight I was only interested in the top piece of the door stop.

Photograph 28: Disassembled Circular Door Stop

And here is the finished turntable weight. It looks quite well with the rubber bands and also matches the platter of Dual 701. The completed and assembled turntable base (less the tonearm) is shown in Photograph 30.

Photograph 29: Finished DIY Turntable Weight

Photograph 30: Finished Turntable Base, Speed Control Box and DIY Turntable Weight

DIY Magnetically Suspended Tonearm

The tonearm was constructed from the ground up in a trial and error fashion. To build a tonearm you will need access to a machining shop as you will require custom machined parts. You will also require a lot of time and patience as the trial and error procedure in making refinements to the tonearm to optimize performance is long and tedious. I wanted to try something unique and the the idea of using a magnetically suspended tonearm seemed like an interesting idea. A magnetically suspended pick-up arm is unlike typical record player tonearms in that there is no fixed pivot point or bearings. Rather the tonearm tube, headshell, cartridge and counterweights are suspended in air by carefully aligned high-strength magnets of opposite polarity. The goal of a magnetically suspended tonearm is to eliminate and minimize the friction that would normally occur at the pivot point and along the bearings.

For the tonearm I used a single thread of monofilament fishing line to act as an alignment guide and as the pivot point for the tonearm. The tonearm was built using a trial and error process so there are no detailed drawings. The pick-up arm is made using furniture grade beech wood. It took about 3 months to construct the tonearm in this manner but the results were well worth the effort. Photographs 31 through 33 show the rear portion of the custom DIY tonearm. I used very fine pick-up wire in the tonearm to carry the signal from the phono cartridge. The signal wires terminate at the bottom of the turntable base and are connected to RCA connectors. The RCA connectors allow you to easily change out the phono cables and I prefer them to a fixed RCA cable.

Photograph 31: Rear of DIY Tonearm and Counterweight

If you look closely in at the mounting details of the tonearm you will see that the pick-up arm is suspended in air by the magnets and that only a single monofilament fishing line thread maintains alignment.

Photograph 32: DIY Counterweight and Tonearm

Photograph 33: DIY Tonearm Controls and Settings

The front half of the tonearm with headshell is shown in Photograph 33. For my DIY turntable project I have attached an Ortofon Samba Low Output Moving Coil (MC) Phono Cartridge ($285US) to the headshell.

Photograph 34: Samba Low Output MC Phono Cartridge Mounted to DIY Tonearm

Finished DIY Turntable (Record Player)

Finally, the DIY record players is complete. Photographs 35 shows a top view of the completed DIY turntable project without the platter. I am using a simple spirit level to set up the turntable.

Photograph 35: Finished DIY Record Player without Turntable Platter

Photograph 36: Finished DIY Hi-Fi Record Player

From start to finish the DIY turntable project took several months to complete. Three months were spent on the DIY tonearm alone. As noted in the beginning of the article the choice of the drive and motor assembly was key to success in this project. The Dual 701 motor is quiet, vibration free and fully adjustable for speed. Other motor assemblies may work but it is likely that most will require some sort of isolation to keep noise and vibration levels low. Take time to choose a good turntable drive and motor assembly. The DIY tonearm is a potentially a very difficult part of the project to duplicate as it will require precision machining of parts. For most hobbyists it will probably make more sense to acquire a premium quality tonearm that has already been assembled and tested. Higher resolution photos are available in the photo gallery, DIY Record Player - front view and DIY Turntable - top view