Voice cards that have not been serviced can result in autotune failing, and the voices not sounding right and inconsistent from voice card to voice card even when autotune succeeds.
The original electrolytic capacitors have long since dried out and stopped performing as they should. This kit contains high quality electrolytic capacitors to replace these failed or failing capacitors and provide decades of stable operation. We provide quality, name brand, long life capacitors. Gold audio grade capacitors are provided for the signal path. Also, metal film resistors are provided to replace several key resistors that will improve oscillator stability.
Other component values can change over time as well, so a full calibration of the voice cards is required in connection with installing this kit. One of the challenges in calibrating and tuning the OB-Xa is the cheap single turn trimmer pot used for the initial frequency of the oscillators which makes it very difficult to get the oscillators in tune. This kit includes replacement multiturn trimmers for the initial frequency of Oscillator 1 and Oscillator 2 on each voice card. The precision the multi turn trimmers afford allow for tuning so precise, it may not be necessary to use the Autotune when the servicing is complete!
Additionally, the voice selection DIP switch block found on the pot board (which is used to disable or enable voices) oxidizes over time and can causes voices to fail. This kit includes a new DIP switch block, and replacements for the polarized capacitors found on that pot board.
This kit contains parts to service 8 OB-Xa voice cards.
This kit requires intermediate level soldering skill and the voice cards require a full calibration after installation. If you’re not comfortable installing this kit and calibrating your synth, please check out our Voice Card Service, where I will install the kit and calibrate the voice cards in one of my OB-Xas.