Anyone tried one of these Aliexpress DMX 12-channel AC dimmer controllers?

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OptykMuse

New member
I just got one of these 12-channel dimming AC controllers from Aliexpress about a week ago to play with to see if I could get it to work for my Christmas show this year as I still use a lot of AC props (currently three 16-channel LOR controllers and a DMX relay).
I was hoping this might get me through this year with a few more AC props as I slowly begin transitioning to just a few pixel strings (also have a controller for those, not in use yet).
Anyway, I saw that it was for 50Hz AC power, and it didn't work at all when I tried it, but there are small jumper pads on the PCB labeled "60Hz" so thought I'd give that a try. After placing a wire jumper between the pads it still didn't work so thought I'd check on this forum to see if anybody else has had success with 60Hz power with one of these.
I'm using Vixen 3.x with Open DMX driving the controllers. This also works fine with the DMX relay I've used so expect it should work just as well with the new board which is a DMX controller. Its DMX LED also blinks like it should as soon as Vixen is running and the dongle is connected to the board.
I just connected the board by itself and set it for the first 12 DMX channels just to see if I could get anything happening with one of my sequences... nada. Checked with an O-scope to see if there were any signals from the outputs on the microcontroller and nothing there. I suspect the firmware is testing for a 50Hz line frequency and probably nothing actually in the firmware to check the 60Hz jumper input. I've reached out to the manufacturer but not much help there.
So if anyone has tried one of these and had success on USA power I'd sure like to hear from you:)
 
Yes, I got those to work, without any incident. What I did was first test them on a virtual light board. That's the simplest. Any problems that happen after that, you know it's a software problem.
 
I did not have to do anything special, but different sellers might ship with different default settings. I have one up on a stage truss and one under the floor, so I can't get to them easily to look. What I did differently from what most here would do is I first plugged it into dedicated DMX software (i.e. QLC+), and made sure it dimmed first. I didn't mess with Christmas stuff until after I verified that. That split the problem in two.

If 50 vs. 60 Hz might be a problem, maybe you could buy one of those US-to-EU plug adapters for a couple bucks, to test.
 
Thanks, that's all great to know. I did more troubleshooting and found I had mis-wired something. It's now working. I used a single LED test light (with appropriate diode and current limiting resistor for 110AC) and tested each channel again with that. I also re-installed a wire jumper on the jumper pads marked "60Hz" just in case.
All channels working! Don't know what the deal was with the o-scope testing...
 
I finally tried this thing with some of my light strings (all were packed away in boxes and didn't come out until November)...
Results were not too good unfortunately. Not sure, but I think it has to do with the 50Hz line frequency vs. 60Hz and probably isn't doing zero-crossing switching correctly or at all.
I first tried an incandescent light string and it did dim but kind of jumpy and not smooth at all. Also, about 3/4 of the time, when I output an intensity ramp-up from zero to max it would start with a full-on flash then a rough ramp-up from zero to full-on. The rest of the ramp-ups were just kind of rough looking.
When I tried an LED string they never shut off, remaining at about 20 or 30% brightness during off time.
So I just figured there's a lot of leakage current getting through the triacs. Too bad, I was looking forward to getting this set up for use this year. Instead I had to just double up some of the props on single controller outputs. It doesn't look too bad as I have them separated by some distance of not too noticeable that they are doing exactly the same thing. This is what I've been doing for several years and was hoping to give all the doubles their own channel this time. Guess I'll go hunting for some unused renard (or LOR or other) someone wants to get rid of next year.
Anyone who has an extra AC controller or two they don't want, let me know :]
 
Ask the seller if the firmware is set to only use 50 hertz and if so, do they have 60 Hz version. The only change would be the timing of the on signal. Also, looks like it is a standard STC micro so maybe you could hack it if you had a few weeks to kill.
 
One thing I would add about these dimmers is that they don't seem to sink a lot of current. I tried mounting it up on a white LED truss in the theater, and just 6 LED floods alone made it run hot. It didn't take too long to cause the whole universe to start flickering. However, I'm running mine on stage this season to switch LED Christmas light strings, and they are doing just fine. I would have expected it to successfully run 2 amps per channel, but it seems the max current limit is lower than that.
 
OptykMuse said:
When I tried an LED string they never shut off, remaining at about 20 or 30% brightness during off time.
So I just figured there's a lot of leakage current getting through the triacs.
Click to expand...

A quick way to test this, is to use an old nightlight with a C7 incandescent bulb in parallel with the LED string. (Or a table lamp with an incandescent bulb)

If this works, a quick fix is to use a plug-in air freshener (without the freshener).


I don't know how this particular board works but I'd expect the 50/60 jumper should just set how the software divides the AC half cycle. 50 Hz timing should still work but the dimming would only be within the lower 60%. The dim should still stay steady at any value.

I'm pretty sure that just increasing the resistive load (as described above) on the output of the TRIAC would get you what you want though.
 
ErnieHorning said:
A quick way to test this, is to use an old nightlight with a C7 incandescent bulb in parallel with the LED string. (Or a table lamp with an incandescent bulb)

If this works, a quick fix is to use a plug-in air freshener (without the freshener).


I don't know how this particular board works but I'd expect the 50/60 jumper should just set how the software divides the AC half cycle. 50 Hz timing should still work but the dimming would only be within the lower 60%. The dim should still stay steady at any value.

I'm pretty sure that just increasing the resistive load (as described above) on the output of the TRIAC would get you what you want though.
Click to expand...

Good call, I missed reading that. It's called a dummy load. He should try that.
 
Lots of good thoughts! I did try to get some info from the seller on the 50/60Hz jumper and they really didn't seem to understand. I tried using it with the jumper in and out and it didn't seem to make any difference in operation. They just told me it would only work with 50Hz line frequency, although we know it does appear to work (to some degree at least) at 60Hz. I did some reading regarding zero-crossing and why it's used... it's supposed to make the triac work more efficiently and with less RF noise generated, but it's been a LONG time since I've learned about it in school so can't say for sure if that's it.
It didn't occur to me to try a resistive load in parallel with the LED's so I think I will try that and not give up on the controller just yet. I'd also like to scope the AC signal and see exactly what's happening to the AC waveform during dimming. That will tell me if zero crossing is working or if the 50/60Hz jumper actually does anything.
 
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