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.

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Fig 1 size=2>Above:  

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.

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Fig 2 size=2>Above :

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 Fig 3 size=2>Above : 

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.

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Fig 4 size=2>Above : 

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Fig 5 size=2>Above :

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.

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Fig 6 size=2>Above : 

Figure 6 show the complete turntable. Notice the tone-arm
cable, it is the one piece Incognito wire kit for the RB250.

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Fig 7 size=2>Above :

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 arm’s
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

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