_MG_7502_thumbFlexible power where you need it – in your modular!

This easy DIY build, based on a supply design from the great Ray Wilson will quickly, easily and cost-effectively set you up with +12 and -12V power rails for your Eurorack power bus. With the same footprint and 4-pin connectors as our ThirdRail 5V solution and  MiniBus power distro board, you can build a neat and scalable solution to your modular power needs in no time at all.

Power is drawn from an external 12V AC adaptor (not supplied).

In conjuction with our ThirdRail, MiniBus and Power products, Dualist forms the heart of your modular power system.

Specifically targeted at entry-level DIY-ers, this project boasts

  • Low part count
  • Clear, simple instructions
  • Complete parts kits, with all parts clearly identified
  • Low tool requirements


Although the regulators in Dualist are rated to deliver up to 1A of power on each rail, we carried out some extensive testing to find out what the optimum real-world capabilities of this PSU would be in a practical application.

We hooked up a whole bunch of test loads (in fact, we developed our DummyLoad module in order to do this) and kept adding more while we watched the load change on the ‘scope.

We found that the best we could realistically claim for this PSU before ripple and voltage drop became an issue was around 350mA per rail – more than enough to power a pretty looong row of modules.

Dualist comes with multiple input and output options to help you integrate it into your modular project and shares the same physical footprint and mounting hole positions as our compatible ThirdRail and MIniBus products (using suitable hardware and spacers, we mount all three on a couple of lengths of 300mm MakerBeam for a complete modular “power sled”).


Important note: Dualist requires a 12V AC power supply; you can’t use a DC power supply with this module or with the Dualist PSU. You must not try to power the Dualist PSU directly from mains voltage!

Dualist requires a 12V AC-AC supply with a 2.5mm barrel socket (we chose the 2.5mm component as we found that in this application they seem to “latch” more securely than equivalent 2.1mm connectors). We’ve found some suitable power supplies here (1A) and here (2A, which we recommend), but both are supplied with 2.1mm connectors; if you buy our complete Dualist kit, you’ll receive a 2.5mm replacement plug as part of the kit, however if you need to obtain one of these they’re available from one of our favourite suppliers.

Build options & instructions

The Dualist build instructions provide a clear guide to making this project.


The full parts list can be found in the build instructions. All of the parts used in this project are easily and widely obtained from any electronics supplier.

Our parts kits contain all of the electronic parts that you’ll need to do the job; the only things that we don’t supply are:

  • Tools
  • Solder
  • Connecting cables


Item Price

PCB only


Full kit

A PCB and all of the additional parts you need to build this project.


Fully assembled & tested

A fully-assembled Dualist, ready to use. Please note that lead times will vary – contact us or see the shop for more details.


Prices include packing & standard (untracked) shipping. All prices are given in GBP, your local price after currency conversion may vary.

All of our products are available from our Etsy shop. Although we make efforts to keep our stock levels as constant as possible, demand might occasionally mean that an item is out of stock. Stock replenishment typically takes less than one week.