FlexReg Single and Dual Rail Regulated Power Supply using 78xx/79xx OR 317/337

Joined 2018
Paid Member
The idea for this PCB is to provide a flexible dual-rail general-purpose regulated power supply for low-power audio projects (e.g. preamps, crossovers, etc.). The design goals for the board and power supply included:
  • Compact with PCB mount transformer & optional connections for an external transformer
  • 15 or 25VA Transformer Options
  • Dual Rail Regulated DC power supply (Positive & Negative)
  • Flexibility for using standard 78xx/79xx family of fixed regulators OR 317/337 adjustable regulators
  • Able to fit in an off-the-shelf Hammond chassis OR into the 10x10 grid of a Modushop / DIYAudio chassis
  • CRCRC pre-filtering before regulators
  • Include ground break rectifier on the PCB
  • Include A/C cap on the PCB
  • Flexibility for 120/240 mains
  • Optional items for users to populate or not:
  • LEDs on PCB (for rail voltage indication and front panel indicator) – optional to populate
  • Snubber circuitry
Thank you to Jim “6L6” for the inspiration, brainstorming, and encouragement on this project!

The first one I built is in a headphone amp using a 15VA transformer and 7812/7912 regulators. I have also built a variable 317/337 version for a BA3 preamp project.

Send me a message if you're interested in trying one.


  • FlexReg Regulated Single Rail Power Supply Build Doc-1.0a.pdf
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  • FlexReg Regulated Single Rail Schematic-1.0a.jpg
    FlexReg Regulated Single Rail Schematic-1.0a.jpg
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  • FlexReg Regulated Single Rail Schematic-1.0a.pdf
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  • FlexReg Regulated Dual Rail Power Supply Build Doc-1.0b.pdf
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  • FlexReg Regulated Dual Rail Schematic-1.0b.jpg
    FlexReg Regulated Dual Rail Schematic-1.0b.jpg
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  • FlexReg Regulated Dual Rail Schematic-1.0b.pdf
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Joined 2018
Paid Member
I have 3 Dual Rail and 5 Single Rail FlexRegs I’d like to send out to anyone who wants to try a build with one. Boards are free to you.

Rules and conditions:
Enter your name in a new post. Write if you want 1 Dual Rail, 1 Single Rail, or 1 of each. These are first come, first serve. Not a raffle format.

If you're in the USA I'll pay shipping. If you're outside the USA, you will need to pay shipping costs. As long as USPS will ship to your country/address, you meet the criteria.

If you'll use the board(s), sign up. You must be willing to build it up and comment on the build within a month or two of receiving it. Please have a project in mind. I don’t want these sitting in a box of PCBs or a drawer.

DIYAudioUser 1 – 1 Dual Rail
DIYAudioUser 2 – 1 Single Rail
DIYAudioUser 3 – 1 of each
Then send me a PM with your mailing details.