4771 Power supply

Just a quick note about the power supply module. The unit in my synth has been heavily modified. From the beginning I noticed that the power was wired so that the power switch did not switch off the 18 volt line, just the positive and negative 9 volt lines. A quick look under the panel shows that the thing is quite ugly below the surface. The kludge mounted directly on the transformer seems to be an 18 volt regulator.

Apart from looking ugly, and the power switch issue, the unit actually delivers clean voltages on all lines. That being said, I still plan to replace the unit with my own design. with the following design goals:

• The front panel controls shall function as the original unit
• Keep the original face plate and transformer
• Use a fuse
• Use a voltage regulator for +18V
• Add OP-amp buffers on the control voltage outputs

To be continued!