[sdiy] +/- 15v from a wall wart...

[Paul Perry]

Well in my experience you usually can't go lower than a nominal 14V AC wart
for +-15.
It's frightening when you do an error budget.
Mains can be up or down 10 or more.
You lose a diode drop in the rectifier.
The regulator is another 2.8 or even 3V if it isn't a low drop out type.

On the bright side, a tiny amount of hum on the power rails can fatten up an
oscillator nicely ;D

Paul perry Melbourne Australia

-----Original Message-----
>Not necessarily.  Depending on the capacity of the wallwart and the load 
>you can usually get away with 9VAC for +/-12VDC, 12VAC for +/-15VDC, 
>etc.  Most AC wallwarts are way over voltage when not fully loaded and 
>the smoothing caps bump up the voltage somewhat.  Use too high an input 
>voltage and you'll need more heatsinking.