About the Precision Optical Encoder Option for the TR-25
What’s the difference between the standard tuning encoder and the optional optical encoder? Optical encoders do not depend on sliding mechanical contacts as the encoder is rotated. They incorporate phototransistors and LEDs to sense rotation, thereby offering much improved reliability and immunity from electrical noise that can confuse digital counting circuits. The optical encoder option allows for a tuning rate of 128 steps per tuning knob revolution versus 40 steps for the standard mechanical encoder. This means that with the tuning step resolution set at 10 Hz (which provides very smooth tuning steps), you will be tuning at 1.28 KHz per revolution with the optical encoder, versus 400 Hz per revolution with the standard encoder. The optical unit is rated for 1 million rotations while the standard encoder is rated for 100,000 rotations. The optical encoder has a better tuning feel than the standard encoder, although the utility and operation of the standard encoder is more than adequate for the tuning function. Neither encoder has click-stops. The optical encoder is not a drop-in replacement for the standard encoder. Since the optical encoder has a larger bushing diameter, the top case half encoder mounting hole must be enlarged. There are several PC board component additions and value changes required to accommodate the optical encoder voltage requirements. These components are surface mounted and are very small. With the selection of this option at the time of the purchase of your TR-25, these changes will be made at the factory for both the kit version and the completely wired unit. Because of the degree of the changes required, the optical encoder option is available only with the initial TR-25 order, and is not available as a user installed option after the TR-25 is shipped. Even though it adds a sizeable premium to the purchase price, this option is highly recommended at the time of purchase in the interest of long term tuning smoothness and reliability.