DIY Direct Drive Turntable (Black Widow Project...English Only)

Diy turntable (sansui sr 535 based…)

Back in 1978 (roughly)… My father gifted me a hi-fi direct drive turntable… It played many years as source of amateur radio
stations and also as main source of then system…

But on the way the virus of improvement and upgrading caught me so I started thinking seriously on it...
In the beginning the thoughts were for an upgrade, but in the course were decided only certain parts to be used and build a
new machine from the beginning...

This point of view has to do with the certainty that the new machine must be able to give the more it can, baring the
limitations of a Direct Drive turntable… The all process of manufacture with the delays in orders and the delivery of
materials and parts lasted roughly 6 months…

The ʽprojectʼ began little by little to take place first in the brain, later in the paper and afterwards in the bench…
The all undertaking concerned…

*** isolation of Power Supply in separate chassis, far from deck with new wiring for current and strobe
* manufacture of new interior sub-chassis (sandwich type with 4 different materials) where motor shall lean and the base of arm too
* manufacture of new exterior chassis where the above sub-chassis shall lean
* new wiring of signal with minimal length and addition of RCA plugs
* stiffen platter with addition of mass of different material
* new head of higher category
**
The parts of the old turntable that would be used were…

*** the motor with incorporated shaft
* the platter
* the arm
* certain steel parts of the chassis**

The turntable was dissolved carefully and detail recording began with measurements as well in order to obtain the custom
parts and materials (acrylic chassis, deflex, lead plate, flanges) that would be used… The all planning forecasted five (5)
basic parts…

*** exterior power supply

main chassis with the motor arm system exterior chassis platter **

The parts were assembled and the work began with first step the build and the wiring of the power supply unit and the
circuit of strobe… It shall be connected with a braid of cables and a special plug of ʽVGAʼ type with the internal chassis
of the turntable… all the capabilities are presents… on-off switch, speed selection, speed control, strobe on-off…

**PSU front view …

**

**
PSU back view … **

the male plug connected to central chassis…

The construction of the most difficult piece of manufacture followed, that was the main chassis, which should be as much as
possible dead and isolated from the mechanic parts, that supposed to be tied up precisely… The electric parts also had to be assembled
so as noises and interjections to be absents…
For this reason five different plates were used build from four (4) different materials for the construction of the two
parts, the ʽupperʼ and the ʽunderʼ part of the main chassis…

The ʽunderʼ part…

Acrylic material of (12) mm thickness (very good absorbent material) Lead plate of (2) mm thickness (exceptional insulator of radiofrequencies and heavy metal for addition of mass) Deflex plate of (20) mm thickness (exceptional anti shock - absorbent)

The ʽupperʼ part…

Steel plate of (2) mm thickness (that of SR 535) acrylic material of (5) mm thickness

the upper and under parts are linked with four (4) fat aluminum screws with four (4) nuts each one (2 internal 2 external)
for horizontal regulation and stability…

Big motor was sunk at the half in fat wall of absorbent material (deflex) and screwed in the upper steel plate…
The electric connections were done and the two chassis were then also tightened and leveled so as to constitute a unique
sandwich-mass where the mechanic and electric parts were assembled…
The turntable with this form plays very well… However, mainly for further isolation reasons as well for appearance, all construction ʽleanedʼ in exterior multilateral chassis with base strengthened from lead plate …

In the beginning another method had been selected, that of placement(in the four big screws holding the upper and under parts of the main chassis), elastic barrels with embraced springs between the screws and no internal nuts… With that way of fixing, the turntable having the two parts of central chassis to sail freely within the barrels and their springs, would be at some way of mass and suspension…

However, after trying this method was rejected because that I wanted was this complicated block to be compact,
stable and solid… I did not want to play with tolerances and de-tunes… So, in this version, the thing it is considered to be mass absorbed…

The arm re-wired with 5N pure copper and the arm** board** fitted with his base and screwed, well isolated from the chassis with
two flanges from skin and thin deflex pad… two high quality female RCAʼs fitted on the upper main chassis behind the arm-
board…

Also Shelter 501 II mounted with the help of a protractor…

Unfortunately, the particular arm has no VTA adjustment, thus the Vertical Tracking Adjustment has to be done with addition
of mats in platter… not so bad…

Exterior chassis became a custom order from acrylic (plexi glass) and its base was strengthened with 2mm lead plate and coated inside with black film…

Four (4) cheap steel feet with elastic bases were added…

In the end, platter was strengthened with lead plate , thus it became system of two elements with much better damping and rejection of aluminum ringing, also became much heavier, thus not so much for the motor to be exhausted…

The three basic parts of turntable with the arm fitted…

During the six (6) months of the construction many things happened, grouches, bad turns and grief and sometimes were
thoughts of dropping everything out of the window and abandoning…

However, I accomplished to proceed, overcoming all the above and in the end the effort was rewarded… The all thing weighs
25 kg… and platter only roughly 5 kg…