6.7A Power Supply Build

I documented my power supply build so everyone can see how it happened. You will see in the first step there is a plastic case with two supplies. Each one is 6.7A and they are going to be wired together to create a +15V/-15V power supply. The mounting is done with 1-1/4” 4/40 screws, washers and lock washers. There are also two 1/4” 4/40 plastic spacers so the power supply bottoms and plastic case do not touch in case of supply heat against the plastic case.


After that I trace out the MIDI/DIN jacks on the side of the plastic box before cutting each one out with an Exacto Knife. They are super sharp and can cut holes out really close. Be careful though, one wrong move….ouch!!!


Once the MIDI/DIN holes are cut I moved onto the IEC jack with fuse holder. That cut was also done with my Exacto Knife to get it as close to the size as possible. This also helps with the midi jacks because you can have enough plastic to screw them in with 2.5mm screws and square nuts. The IEC also has tabs so if the hole is the correct size it locks into the plastic and stays put when plugging and unplugging.

Next is cutting all of the wire to size and putting Female Terminal Connects on all of the wire going to the IEC jack and stripping the wire to be on the supplies and soldered to the MIDI jacks. This step is the most important because the ground wire in my box is done with 12G wire and all of the power if done with 16G. From doing car audio we always used thicker wire with the ground. The shorter the run of cable the better so there isn’t a bunch of wire in a corner of the box. It could also cause EMI noise in your audio lines.



Once the wiring is done and the MIDI jacks are wired and soldered I go get a multimeter and test all of the jacks to make sure the power is giving +15V where needed and -15V where needed. There is a regulator board inside each of my cases that regulate the boards to +12 /-12. Running the system this way has been documented on the ELBY Designs site. It seems to be solid. If you do not know about voltage regulators you can always buy +12/-12 supplies and just go straight 12volts.

You can see my power MIDI/DIN jacks are finished. Then i GOO-Gone the marker off. Please note that people in your studio SHOULD know there is power running on MIDI/DIN jacks. If one of these gets plugged into any gear you could have a total gear meltdown. My studio speed has become much slower now that there is power running along MIDI lines. Be CAREFUL if you choose to run things this way. MIDI jacks have plenty of pins and usually are handy for running over 10’ lengths for connecting gear/power/audio in certain situations.


My final wiring is below. As you can tell I like clean wiring and simple design. I found the plastic case in the trash and the supplies were 30$ each online (Jameco.com). Wiring is about 5$ with a 3$ IEC plug and 1$ fuse. Pretty simple project that took me about 1 hour.


Case is powered and making amazing sounds!