I kept the original transformer after measuring it and found out it was 20.9 VRMS across each half of it's secondary windings (it had a center-tapped secondary). That translates to 29.5VPK. I used this website to help design the rectifier to get the AC line voltage to DC. I decided upon using a LM317 3-Terminal Adjustable Voltage Regulator because it was inexpensive, easy to use, and did everything I wanted with a very small component count. (Just a warning, the pin-out of this regulator is different than fixed voltage regulators, so make sure to use the correct pins for this chip.) I based my circuit on the application notes starting on page 9 of this schematic. There's also a lot of interesting applications of this regulator starting on page 16 of that data sheet. I had a ten-turn potentiometer that I used for the adjustment so I can have supreme control over the output voltage.
|The real thing|
|My hand-bent aluminum case|
|Lots of noise at 3.3V output|
Edit: After looking through some of the pictures and comparing it to the schematic, I noticed I never installed the 100uF output capacitor (oops). I don't have an oscilloscope at home (I'm still on Christmas break) so it'll have to wait until I go back to school next week to see if that improved the noise issues.