DIY Turntable Project
I have found this to be a very exciting learning experience and recommend anyone interested to find an old turntable and to use the parts for building your own "high-end" turntable. For those with better cash flow, several kits are available.
I used an old Logic DM101 turntable as parts. I only used the main platter bearing, the sub platter, main platter and the motor with its electronic control. Any old turntable can be used for parts, key things to look for are a quality platter bearing and preferably if the platter bearing housing is fitted with screws.
I selected wood to construct the new turntable and the main reason is the fact that I have the means to work with wood.
First step to consider was the basic design, with or without sub chassis. All the turntables I have are suspended and therefore I decided on a non-suspended design. I also believe that a non-suspended type turntable will better create the illusion of pace and rhythm. The main disadvantage, however, is that said type will be more susceptible for external resonance and or vibration.
Figure 1 shows the bottom triangle or shelf of the new turntable. I constructed this section using four different pieces of wood, joint together using biscuits and glue. You will notice that the joints are of high quality and the reason is to have a strong one-piece design. The main reason for using four pieces of wood is to prevent or minimize the risk of having the shelf resonating during use. The joints should also act as high resistance areas and should therefore minimize the transfer of vibration energy. I used three copper cones as feet for the bottom shelf and not the traditional rubber type feet found on turntables. These cones then fit into round wood pieces. Important for optimum performance will be the use of a dedicated wall rack with this type of design.
Fig 2Above :
Fig 3Above :
Figure 2 shows the main parts of the new turntable, being the shelf and the top part. The top part is important as this can be considered as the actual turntable. This top part is further isolated from the bottom shelf with the cork fitted in-between them. With a suspended design typically springs or some type of suspension would have replaced the cork. Is the cork the best material to use? The cork I use is a compound of rubber and cork. This to my knowledge will create a high resistance area for upper bass and higher frequencies. Important for me was to have the top part of one piece and thus strong and rigid. In addition the total area of the top part must be as small as possible in order to increase the natural resonance point of the top part. The principle of having as little as possible-joining points between the stylus and the LP was also considered. The top part in my opinion will present a very rigid base for the arm and the platter bearing.
Fig 4Above :
Fig 5Above :
Figure 4 shows the platter bearing fitted. Figure 5 is a top view of the turntable without the outer platter. This view is important as it shows how the motor is placed as well as the one bolt between the top part and the lower part or shelf. The bolt is also isolated via rubber from both the top and shelf part in order to prevent it from transmitting high-energy resonance between the two parts.
Fig 6Above :
Figure 6 show the complete turntable. Notice the tone-arm cable, it is the one piece Incognito wire kit for the RB250.
Fig 7Above :
Figure 7 shows my heavily modified RB250 arm. The arm is completely re-wired using Incognito wiring from Germany. The Incognito VTA adjuster is also fitted. The most significant improvement to the armís performance is the brass rear end stub and counter weight. The counter weight is off center as to align its center of gravity in line with the stylus. The rear stub has a rubber ring between the lib on the stub and the arm wand. Reason for this is to damp upper bass frequencies in the arm. The thread on the rear stub is made such that it is better coupled to the arm wand using a high torque fit.
Important with the design of this turntable is that every arm I use will have its own top part. Reason is to prevent the use of sound degrading arm boards and to maintain the rigidity between arm and platter.
What does it sound like?
It has the behavior of a thoroughbred and one quickly realizes that there is lots of potential. The weakness right now is the fact that I do not have a dedicated wall shelf. This is one of my future projects and when completed I will be in a better position to give an in-depth review. I had it on show for example in a dedicated "high-end" shop a while ago and customers were completely surprised by the quality of replay offered by vinyl and then this turntable.
Photos and text by Bushman