SY-1 Pearl Syncussion clone - fixing the PSU noise

Published on Jul 2, 2018 Stereoping

"The first batch of the brilliant SY-1 Syncussion clones from the human comparator seemed to have an issue with the negative power supply (TL497 inverter), soiling an ennoying high frequent noise into the audio path. There are several discussions and suggestions for fixing in different discussion boards. On learning from Shruthi filter schematics i came across another voltage inverter (LT1054) and wanted to give it a try. To my own surprise it worked right away, the noise completely disappeared, the unit still worked (unbeleivable!) and the new inverter keeps perfectly cool. I built a test setting with a switch allowing to flip from the original negative supply to a breadboarded LT1054 supply. You will directly hear and see the difference.

Second half of the demo shows some pictures how my alternative negative supply looks like now. It is soldered directly in place after removing the TL497 and some unused components. The background music is of course from the SY-1 (after PSU-conversion) together with the impOSCar.

There is an article on my site with more details about this hack."