Getting the 3 blinking blue lights on the uZeus when I plug just these three modules in.

The VRL or the Subharm will work fine if I unplug one of them.

Is it the wall wart? I bought the case and the power supply used and the WW says Tiptop audio on it. Says is outputs 13.1v @ 1.1 amps.

The Subharmonicon pulls 360 mA +12V.
The Voltage Lab pulls 525 mA +12V.
The MSCALE pulls 6 mA +12V.

So, we're up to 891mA @ 12V, very close to the limit of the uZEUS 13.5V 1000mA PSU. Step up to the uZEUS Boost 3000mA 13V Universal Power Adaptor.

I grew my first modular build into four 104HP skiffs, each powered by a uZEUS. It was my experience that a conservative approach was necessary and often found myself needing more power per skiff. The uZEUS was often temperamental with certain modules, mostly those wanting more and consistent draw and operating on arduino/pi/microcontroller/single-board type builds. The flying bus cables were kind of a drag to manage and keep organized. I still have three of those skiffs but now only use one with a 3000mA 13V PSU.

Good, clean, consistent power is vital.

Thanks - I had a 12v 3a adapter that I was close to trying. But fear made me order the Boost instead and not take a chance!

I'll just have to wait.


Yep, that's a very serious overloading issue there. You don't want those indicators doing anything other than being on.

The problem here is that you're trying to run the power supply right up against (and over...we'll get to that) the current limits of those uZeuses. NEVER, EVER do this! First of all, heavy loading on a power supply leads to heat, and heat leads to a bunch of problems, such as component damage in the P/S, excess heat throwing settings and patches off, and potentially module damage if the P/S fails in a few specific ways.

Your rule of thumb with current loading in a synthesizer is to make sure that the P/S (the module's DC bus outputs, not the wallwart or power brick) exceeds the amperage load from the modules by at least 1/4th...if not more (I prefer 1/3rd excess amperage headroom)! This lowers the heat on the supply, which makes it work easier, but it also fixes a very sneaky issue that you've apparently seen first-hand here: inrush loading.

Inrush loading is a simple fact of the physics of introducing power to a circuit. In the first milliseconds at power-up, circuits can draw more than their rated amperage draw, and this inrush can exceed this by quite a bit if the circuit in question contains things such as tubes, major inductors, etc. Sure, it stops doing this in a tiny fraction of a second, but that's enough time to trash a compromised component, and the best way to get THOSE is to keep pushing the P/S too hard! And this is precisely why those uZeus indicators are yelling at's trying to get you to STOP trying to blow it up!

Another way to push things too hard is to take something with a big current draw and stick it in a cab with OTHER things that ALSO have a huge current draw. These often tend to be patchables that fit the Eurorack standard, but which don't belong in a system cab...such as the Subby and the VRL. If those have cabs of their own...USE THEM. Eurorack cabs need to be used for things which DON'T have their own housings and power, because there's a whole lot of those, and it's infinitely easier to have something like a Subharmonicon out of the main cab and in its OEM powered cab than it would to have a few VCO modules or whatever laying loose on your workspace with a flying bus attached. It's also cheaper, since you're not paying TWICE to house and power those devices. You should probably step back, take a deep breath, and rethink what you're doing here. Try and define what the Eurorack cab should be used for in your workflow, your music, etc. What should go in there? What is that system supposed to do? Is this something that you'll change your mind on in a month's time, or are you good with this for a matter of several YEARS time? All of these and more are questions you should be asking before spending any more money WITHOUT a game plan for this...and you DO need to be sorting this out before you wind up damaging equipment or, for that matter, winding up with gear you thought you needed when you potentially DIDN'T need it!