Electronic Speed Control for VPI and Other Turntables
VPI's ADS Analog Drive System Speed Controller provides extremely accurate speed control to your turntable. It includes two pure analog frequency generators featuring low distortion and noise. Created by VPI Director of Electrical Engineering, Michael Bettinger, the ADS has a high current Class-A/B amplifier that is transformer-coupled to the turntable output. It features analog control logic for low noise operation and 33/45 RPM analog speed adjustment controls with center detente positions that are factory calibrated.
Highly Accurate and Easy to Use
The ADS works with VPI turntables and also with other turntables that use an AC Synchronous motor which draw less than 10 watt. Just plug your compatible turntable into the back outlet of the ADS, and you are ready to go. Please note that it is not compatible with turntables that use an external power supply, such as a the commonly seen 'wall wart' type.
The ADS is intended to remain powered on during listening sessions, allowing the analog oscillators to remain warmed up for lowest distortion. There is a separate run/stop switch to control the motor operation, which is used to control the starting and stopping of the motor.
To operate the ADS apply power using the front panel power switch, power on is indicated by the illuminated blue bar included in the switch. Next turn on power switch on the motor and leave in the on position. The turntable is now started and stopped using the run stop switch in the middle of the ADS faceplate. Speed is chosen using the 33/45 RPM switch.
The ADS utilizes separate 60 Hz and 81 Hz oscillators to eliminate unnecessary switching circuitry in the oscillator circuits for long term speed stability and low oscillator distortion. LEDs indicate the Run/Stop condition and chosen speed. Speed adjustment controls provide a center detent position that is factory calibrated to 60 and 81Hz +/- .02 Hz in their center detent position. The controls also provide fine speed adjustment of approximately 3 Hz through continuously variable linear adjustment controls.
