OTS -AC controller removed, not as bright on 24 DC


New elf
Sep 6, 2011

I have several 30m sets of OTS (Santa's Christmas Wonderland ex KMART) strings which I was planning to fill in some trees with, they have a 240v [50hz] - 24v AC [50hz] plugpack that powers the controller.

My intention was to cut of the controllers, and run the strings via the DMX controllers I have @ 24v, however when connected directly to 24v DC, they are not as bright as factory.

I measured the voltage coming out of the factory controller (3 wires - 2 channels) to each strings as being 24v DC. Thus happly whopped off the controller and connected it to the 24v DC power supply. The lights are pretty dim, the only way I can achieve the same brightness as achieved using the 'original controller' is to ramp up the power supply to its maximum (and the multimeter reads 27v).

The question for you all that have been doing this for longer (first animated display this year), how can I be reading the same voltage across the string of lights but yet have a different brightness ( I undersand if the resistors had changed, but nothing has - simply unplugged one and plugged in the other).

One oddity I did pickup is with the original controller, the output is 24v DC - [100hz] thus are my multimeter's only showing the RMS value - in essence the voltage is peaking higher?

Will the DMX Controllers rated up to 24v last if I ramp up the input voltage 1-2 volts?

Other info:

I have everything for this Xmas ready to go - 80% of the display is 24v dc - 100 led strings I had made in china this year, routed back to 24ch -LT-880 and 27ch -EasyDMX (from ray wu) DMX controllers (2 of each). I'm running everything from 24v switchmode power supplies.

Thanks in advance.


Grandpa Elf
Community project designer
Generous elf
Jun 12, 2010
Victoria Point (Brisbane)
You'll need a DC voltage of around 28V - 30V to drive LED strings that originally supplied by a 24V AC plug pack.

You are correct about getting misleading readings when measuring the pulsed DC output of the controller.

The Kmart strings would follow the same general principles as the Big W ones, so check out the Big W threads in this same forum section.