First Project.

[adam]

Hi,  i'm working on my first project (a filter) and i need some help.  first
of all, i need -5, +5, +12, gnd (i am using a cem3378).  i know i can use an
X volt supply (12 < X < 35), a +5v voltage regulator, and a +12v regulator,
for 2 out of three, but how do i get the -5(relative to ground)??

my friend claims that if i use a 20 volt supply then i can use +5 as the
ground, ground as -5, and +17 as +12, but this sounds really wonky.

Please help! (or i'll follow his advice, likely blowing up everything) 



Is there a nice simple intro to diy synthmaking _online_?

Thanks.
adam.