DIY Power Supply 2

More power! It's sort of a mantra when constructing a modular synthesizer. The type of power supply being used is arguably more important than any other part of the synth and it's wise to get the largest supply you can. This is especially true if you might ever want to expand your system. A high output power supply will last you a while. I'm currently on my fourth power supply.

My first DIY supply - the third overall

When choosing this newest power supply, I had a few considerations. For example, there are the common linear power supplies which are bulky and can weigh a few pounds, and then there are the far lighter switching power supplies. Currently, only Tiptop Audio offers a switching supply and it is integrated into their Zeus bus boards. Each board can pull up to 1.2A from a laptop style power brick and can be daisy chained together to power a large system if your power brick has the amperage to spare. Additionally the Tiptop boards give you a lot of configuration options and headers for both the common Doepfer style connectors and less common Analogue Systems connector.

Price was my second consideration. Tiptop's linear powered Zeus boards are 160 USD each. To safely power a 9U eurorack system would require an investment of over 300 dollars. Coincidentally, this is about the price of most higher end synth modules. For myself, the glamour of a three hundred dollar oscillator outshines the practicality of a working power supply. Thus I feel these bus boards are pretty expensive for the relative benefits offered. And I already own a set of bus boards. But if you are just starting a system they might not be a bad choice at all!

Tiptop Audio also makes a power module called the uZeus which offers an all-in-one solution with limitations. Each comes with a bus board made from ribbon cable and can power up to 1000 ma worth of modules. One should be enough to power 6U of eurorack. On the downside, these cannot be daisy chained to pull more power so you will need a wall wart for each uZeus. uZeus must also be mounted in the front of the system so it competes for space with your other modules.

I have a uZeus and it's pretty nice. However I blew out a resister and led on it when trying to integrate a dual power supply for my ever expanding and power hungry system. Something was hooked up backwards or grounded incorrectly and it starting smoking when powered on. Oops! It still works without the visual indicator but I doubt it has much resale value. This also convinced me to not try and integrate different power systems in my synth. With my most recent upgrade I decided to just get one power supply large enough to power everything.

Newer, beefier supply and it's oversized case

Instead of repurchasing bus boards and a power brick I went with a linear power supply. I bought a PowerOne HCC1.5-3-A from feeBay. It puts out 3.4 amps worth of power which is enough for a fairly substantial amount of modules. And it was only 12 dollars! On hand was a cheap toolbox from Harbor Freight that I picked up for a mini system. It's large enough to house the PSU and one additional row of eurorack.

At this point, let me state that this is not a tutorial on building power supplies. I have no knowledge of electrical engineering other than my own DIY experiences. In addition to the uZeus frying LEDs, I've also blown another linear PSU and pretty sure I caused a brown out on my block last summer for not grounding something else correctly. If you have some experience with electricity and want to roll your own, consult this excellent post on the Muff Wiggler synth forum.

First I had to clean the foam out of the bottom because I'm pretty sure the heat from the transformer would have melted it. It was glued in pretty well and was took far longer than I expected. Once that was done I drilled a few holes in the case and mounted the PSU with aluminum standoffs. Afterwards I recycled the power switch, fuse holder, and CB connector (to deliver power to the main case) from my first DIY supply and soldered the necessary connections.

Foam removed and connections made

Pay attention to the fuse recommendation on the PSU!

On first power up it blew a fuse. After replacing the fuse it worked two more times before blowing the fuse again. This cycle of blowing fuses continued until I spent over 20 dollars on replacements and decided enough was enough. The solution came in two fixes. The first was simple enough - I had been using 0.6A and 1A fuses instead of the recommended 2A. Second, I had not connected the common ground of the PSU to it's chasis. Since these two fixes were made everything has been great. Hopefully my synth doesn't surpass this supply for quite a while.