<img class=" titleimg" alt="" src="/images/audio/turntable/tt-complete2.jpg"/>
Although my first turntable prototype worked quite well, it had a few issues, each of these is looked at here:
- The area under the platter was too thin, and tended to concentrate vibration around the platter main bearing sleeve. This was fixed by brute force to avoid vibration in the first place (a very large granite / MDF block below the plinth).
- The positioning of the motor and circuit led to some noise, and only earthing to motor prevented it.
- It left the stylus too exposed, and because of its design could not easily be covered with a lid. This turned out to be the biggest weak point! While trying to clean under the turntable I caught the duster on the stylus. This led to the demise of an Ortofon 2M black stylus; which at £300 led me to rethink the design.
So in summary:
- First and foremost, the stylus is very expensive, and needs to be protected! It is better if the plinth covers the stylus to avoid damage. It's even better still if it is possible to cover the turntable when not in use.
- The plinth must be of a fairly consistent thickness, except around the motor, where it obviously must be thin to allow the motor to be fitted. The motor vibrates as it's turning, and should be isolated as best possible from the plinth.
- To avoid noise from the motor, it will be mounted on an 4mm aluminum plate. This plate will not be screwed into the plinth, it will be set in a Silicone bed. The motor will be screwed to the metal plate as the motor needs to be as stable as possible, it will be stuck to the metal plate using a 1.5mm self adhesive foam. Further, it will need small rubber washers on the back of the motor to isolate the screws from the aluminium.
- Motor wiring will be kept as far behind the arm as possible right at the back of the unit, further the wires going to the motor will be twisted together in an attempt to remove buzz.
- Sorbothene will be used between the two parts of the plinth to further reduce vibration reaching the turntable.
These lessons will be integrated into the next turntable.