LT1033 & LT1085 BASED POWER SUPPLY - THE FROG

Introduction Design Build Measure

In the above linked pages I attempt to comprehensively describe my 3-pin regulated power supply project. This project was originally motivated by an AudioXpress article (January 2009). In the hope of learning more I set out to design my own power supply.

I chose to work with adjustable 3-pin voltage regulators for several reasons:

1. Low cost
2. Easily available
3. Easy to implement
4. Can achieve high performance
5. Good first project to learn about power supplies

Can you build a better supply? Yes (See reference list). Are the differences audible? I have no personal experience but I can say that no one has ever shown any measurements to corroborate claimed audible differences.

I settled on the LT1033 and LT1085 because they are pin compatible with the LM317 and LM337 but have higher max current and lower output impedance (Zout). They are getting more difficult to find, especially the LT1033 which is out of production. Nevertheless they are still obtainable, and if you can't get them, just use the LM versions and performance will be almost as good.