Hi, I have run into an issue that I find confusing regarding DC power to display elements. To set the stage, here is one example: - (8) 3ch DMX controllers, hooked up to various blinky things - Mean Well 12v 50a power supply (or a professional benchtop adjustable power supply) If I hook up all 8 controllers to the power supply (basically vampire-tap the positive and negative), with each drawing (according to my bench power supply) between .03 -.3 amps @ 12v, I get weird results. That is, some channels will sometimes respond, others will flicker and some will not respond at all. I measured the voltage at the end of the 12v run and it was 12 volts. Current draw (according to my benchtop PS) was 1.7a, well below the 5a of this power supply, and certainly well below that of the Mean Well. After a lot of troubleshooting, I cut up some cheap 12v 1a wall-warts and hooked one up to every 2 controllers. Everything worked as expected. Another example: I have qty 20 LED popcorn strobes. The are a very simple construction, using a 555 timer and 4 piranha white LEDs in series, run at 12 volts (regulator is the Mean Well 12v 50a power supply). I attach these into a standard straight-through (in parallel) C9 cord, and attached to the power supply. The more I add, the dimmer they become, and their behavior appears to be not that of running off the 555 timer, but rather that of the circuit resetting. Again, I checked voltage at the end and it was 12v, and the amp draw was well under the 50 amps (in the order of single digits). Again, if I set an individual power supply to 2-3 of them, they worked perfectly, but once I add more in parallel, it was erratic. [SIZE=78%] [/SIZE] My question is why? Why can't I treat a leg of 12v power kinda like AC, where one can just tap into it as long as you don't overrun the total amps for the power supply? Second question I have is related to the one above, depending on the answer. If, in the case above, I need to use a constant-current power supply, what happens when power gets manipulated through PWM on a voltage regulator? I've seen many DMX lighting controllers that use a 7912 with PWM, so doesn't that kinda defeat the purpose of constant-current? I'm totally confused.