Love creating hifi equipment
Joined 2023
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Belt-driven turntables make up a very large proportion of the vinyl turntable range. Because the micro-elasticity of the belt itself can filter out most of the vibrations of the drive motor and the torque output that is not absolutely continuous, the sound of the belt machine is relatively analogous.
However, when you debug the speed of the belt turntable, you will find that the adjusted speed of the turntable occasionally changes slightly. For example, the originally debugged 33.33rpm changed to 33.42rpm after a few months. I think the reasons may be as follows.
1. Changes in room temperature will affect the softness and hardness of the belt. When the room temperature changes from low to high, the belt will soften slightly and the rotation speed will slow down slightly. On the contrary, the rotation speed will become faster. (For example, during the few months from winter to summer, the change in room temperature may exceed 20 degrees. According to observations, when the motor speed remains unchanged, the change in speed caused by room temperature is about 0.01-0.1rpm.) In addition, the belt Aging will also cause the belt to become harder and the rotation speed to become faster.
2. The tightness of the belt will affect the speed of rotation. Some record players have external motors, and such motors can adjust the tightness of the belt by adjusting the distance between the motor and the record player. When the motor speed remains unchanged, generally the tighter the belt is pulled, the slower the turntable's speed will be, and conversely, the speed will become faster. We can use this simple rule to fine-tune the speed. However, there is an appropriate range for adjusting the belt tension. If it is too tight, the friction between the motor shaft and the turntable shaft will increase significantly, affecting the stability of the rotation. If it is too loose, it will slip and affect the rotation accuracy.
3. The potentiometer for adjusting the speed was accidentally touched. The motor of some turntables can fine-tune the rotation speed. If the knob is accidentally touched, it will definitely cause the rotation speed of the motor to change, thus affecting the rotation speed of the turntable.
4. The speed control schemes of a small number of motors do not include phase locking or dynamic speed monitoring and other similar correction mechanisms. When the mains voltage changes greatly, the speed of such motors will change significantly, sometimes even exceeding 0.2-0.3 revolutions per revolution. minute. If this is ultimately determined to be the case, it may require frequent adjustments during use, or simply upgrade to a new motor.
The above are the common reasons that affect the rotation speed of belt vinyl turntables. I personally will occasionally measure the rotation speed of the turntable. If the deviation is large, such as exceeding 0.05rpm, I will make adjustments. If new reasons are discovered in the future, I will continue to add them.
Love creating hifi equipment
Joined 2023
Paid Member
Love creating hifi equipment
Joined 2023
Paid Member