saint gillis
Well-known member
Here's a cheap trick if you are annoyed by a a high frequency note in the background of the sound of a Roland SH-3A synthesizer
The SH-3A works by generating a high pitch squarewave note divided in several lower octaves
The VCO is buffered by a common-emitter transistor stage and the note bleeds in the positive rail of the PSU
If the collector resistor on your version is a 2K2, change it for a 10K as on latter versions :
Add a 1000µ 25V capacitor between V+ and ground at the point where V+ reaches the 10K resistor :
The SH-3A works by generating a high pitch squarewave note divided in several lower octaves
The VCO is buffered by a common-emitter transistor stage and the note bleeds in the positive rail of the PSU
If the collector resistor on your version is a 2K2, change it for a 10K as on latter versions :
Add a 1000µ 25V capacitor between V+ and ground at the point where V+ reaches the 10K resistor :
