As the number of my Eurorack modular cases climbs, I find myself needing more power bricks. With the exception of one small case that runs off an AC supply, all of them can work with 15-volt DC supplies. Now, with eleven cases needing DC wall supplies, and having only seven available, I just bought three more. I like to have bricks available to take when playing out, so that my studio setup doesn’t have to be disturbed.

I thought it might be helpful to write a post describing the considerations going into such a purchase.

Specifications

• First of course is the voltage. The very first Eurorack power supply I bought was a 4ms Company Row Power 40. It came with a 19-volt supply. But all Row Power modules can use 15-19V supplies. Some of my other cases have supplies that stipulate 15V input, and so I standardized on 15 volts, so that I can generally use any of my bricks with any case.
• Next comes amperage, also specified sometimes by watts. Most 3U (1 row) cases will need no more than 2.5-3.5A. Six and nine U (2 and 3-row) cases may need more.
• Two barrel sizes are common, 2.1mm and 2.5mm diameter. This is specified by the size of the power inlet jack on the supply module or case. All of mine, except one, are 2.1mm.
• Barrel polarity: center-positive
• AC power cables come in two basic types: 2-wire and 3-wire. A power cable is usually an extra part that does not come with the brick. This is because the bricks themselves can use a wide range of AC voltages, from 100 to 240 volts. So the power cable needed depends on the standard used by the country where you’re located.
• Isolated or non-isolated. Earth grounding is passed through to the common terminal (the negative, or ground terminal) of the barrel connector in non-isolated designs. One model in my list has a 3-wire cable with an earth plug, and yet it does not pass the earth to the barrel connector. Two other models do. Whether to isolate or not seems to be a controversial question among modular users. I’ve decided that having the metal jacks on my modules hooked to Earth is a good thing for safety. But not all of my supplies do it. Thus, I have added a banana jack on each case that can be routed to an Earth ground, if desired.

Five models

2.67A with a three-wire inlet that nevertheless is isolated.

Quantity: 2

2.67A with a two-wire cable

Quantity: 3

6.6A with a three-wire non-isolated cable, bought to power my 9U case, which has two Row Power 40 modules.

Quantity: 1

3.4A, 2.5mm barrel, bought to go with the one uZeus power module

Quantity: 1

3.34A with a two-wire cable, bought as a better alternative to the Meanwell units: new design and more amps.

Quantity: 3