#1

I’ve been kicking around the idea of making a Frequency Central tiny PSU or StupidUSBPower for doing a round of prototyping, but then I remembered that I had a circuitspecialists.com psu / breadboard thing sitting in the back of my studio from when I used to do more electronics work. Anyway its got variable 0–15, 0 – -15 @ 500ma and 5v @ 1a built in. I’m really new to bi-power power.

Should this thing work fine for testing and prototyping eurorack-powered circuits, or does anyone else out there use anything like this? Is there a simple way/circuit to test it? I imagine there might be an issue with the ground being attached to earth ground and not the ± circuit ground. I can get +12 and -12 when metering the corresponding terminals to the ground terminal as seen in the pics!

This link is to a newer version. Mine’s the same but w/o the LCD screens.

If this could work it might prove to be a cheap and effective way to get a minimal standalone system for lots of folks to get into prototyping all in one place!

#2

Looks totally fine to me, and seems like a good solution to do some bipolar power prototyping. You could hook up a simple protection mechanism with some PTC thermistor fuses & diodes if you want to protect your downstream effort from shorts.

#3

Excellent thank you!

For that downstream protection is that basically just running a fuse and diode in the path of each voltage before hitting the fun stuff?

#4

Here’s an example.

I’m referring to F1, F2, D1 and D2 on the far-right hand side.

PTCs are temperature sensitive resistors. As current flows through, some voltage is dropped and they heat up a little. As they heat up their resistance also increases, which further increases temperature. If there’s a short downstream, this feedback loop will run-away and the PTC will go to a very high resistance value (essentially fuse-breaking the circuit). The purpose of the diodes, is to provide a path to ground in case of connecting things backward.

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#5

excellent! thank you! I’ll give it a try.