This is where I am at with mine.
The power distribution block.
Using a 5V linear regulator and the MAX1044 charge pump,
Input 9V via barrel plug ...
Outputs -9, 0, 4. 5, 5, 9 and 18V
-9, 4.5 and 18 taps will service the analog TL072 based input and output buffers. With 13.5+/- to operate in, it...