A rather nice, cheap LED mover

[paulears]

As so often happens we get called in when people have systems they can't make work. I don't do nightclub stuff - it's never interested me, but a friend suggested me to a club owner - who just said we need help.

 

He'd bought some Thomann Stairville MH-50 LED movers - and I sort of sighed. He showed me the control - which seemed a bit odd. A Masterpiece working a few 250W discharge movers, with the faders set to operate a few par cans of various sizes and colours around the venue via "dimmer things in a room somewhere" . There were some Abstract mirror scans run from a dedicated controller, another 12 channel DMX controller doing something else, and an ancient pulsar 0-10v control running something else - didn't find out what. Every system installed on top of the others.

 

I've worked out I can run most opt this from a magicq - which will also be useful as none of the staff know anything about lighting at all. I took one of the Stairvilles home, not expecting much. It's bright - actually, very bright for such a tiny fixture and the beam angle wasn't as narrow as I expected to try to keep up brightness levels with a low power light source. Gobo sharpness was really good too. Colours weren't that good, I felt. The red was orange, not red, and the UV was just blue. That said, apart from being damn noisy it was pretty good for this use. I'd NOT want to use these in theatre. In my living room, it was too loud to hear the TV properly - so a bunch of them over the stage would be horrible. They move quickly, but not speedy - and this also adds to the noise levels. However, output wise - I'm pretty impressed. Dimming is by dimming the LED light source and although a bit steppy at the bottom, works ok. The lowest level before off is still bright enough I can't look into it directly, though. I did many of my patching and fiddling tests by mistake at 50% and didn't notice - which says something. I'm usually a bit of LED sceptic - but they have the main thing - brightness,pretty well nailed.

 

Cons

Apart from noise, gobo and prism rotation is weak. There is no really slow rotation available, and the prism rotation doesn't reverse. The LED light source also has the plane of sharp focus on the gobo wheel very narrow - so the pebbly-glass gobo can be defocussed to get some nice effects - but the purple with spots glass gobo needs a focus tweak compared with the others to be sharp - and the range of adjustment on the pebble gobo is very wide. I'm not that keen on the supplied stock ones, but I guess they're ok - just some of the common shapes aren't there. So no straight line, or row of dots and there's some that just look, well, Klingon!

[Brian]

Is it just fan noise?

 

At £370 each it'd be economic to replace the fans with something quieter.

[KevinE]

I've also been impressed with the performance of the latest of these LED disco movers. But I do wonder how the LEDs will perform when they've clocked up a few hours. The LED engines (as they've called them) are also supplied by the usual tatty-looking chinese switch-mode modules. Review them in another 5 years!

[paulears]

There isn't really very much space inside - I took a few quick pics if these help in any way because I had to open one up when a gobo fell out! Inside everything is quite compact. The gobos are in small metal housings, with a plastic toothed ring on the outside that engages is a large diameter cog for the rotation. To fit a different gobo is done by removing 3 small screws, and then lifting off the metal plate that is on the reverse side of the toothed ring. This simply slides in with a sprung strip that pushes against the slotted backplate, and it just clicks into place. I can't make them fall out by whaling the unit - so I assume they just weren't clicked home properly in the factory. You can't really see the light source, being contained in a heatsink block. The place yesterday eve had some windows open so the venue was lit by daylight coming in and it was easy to see what was happening - no complaints on brightness. If they get used a lot, then I expect even if the light source did have a limited lifespan, then buying ten of these or one big one from the big boys would make sense. It does seem that nowadays it's quantity that we see when people go 'wow' - so a clubby type venue who want impact and don't really care about noise could do pretty well with these.

[bigclive]

I have noticed that in many high power architectural LED applications, the LEDs are actually being let down by the power supplies. They don't always fail with dignity either. Sometimes they go dim and flickery (dry caps?) or just start strobing on and off.

 

Once the LED manufacturing industry has standardised on a form for the higher power LEDs like they did for the original Luxeon star type devices, it may well be viable to dig out the light engines and simply replace the LED, since the heatsink is likely to be the only part of the engine that is custom built for the fixture.

 

That said, the reliability of high power whites seems to be evolving rapidly.