9v from 18v "wall wart"

[sjturbo]

  I have an 18v 1A "wall wart" (HP computer supply) and wonder if I can make a multi 9v and 18v to supply my pedal board?  Would a simple volage divider do it?

Thanks,
Steve

[nelson]

Voltage divider would do it, if your pedal board stayed the same all the time (guess not).

Best bet is probably heatsinked LM317.

[Paul Perry (Frostwave)]

Have a think about what you are going to use the 9 and 18v supplies for, and whether the grounds are in contact.
Also, how much current do you want at 9v?
Because, sure you can use an adjustable regulator ot a LM7809, but you are dropping at least 9v across the reg, so if you have say 200mA, there is almost 2 watts heat right there!!!
I fthe 18v is just for a boost that requires a single 18v supply, then sure, you can run the original supply tot he boost & use a reg to whack down to 9v for the rest, if the reg can handle the heat.