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Chinese LED wash fixture with zoom


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There seem to be more and more Chinese LED moving head washes becoming available with zoom. My question is to do with how the actual zoom is carried out. I've never seen one apart, so I wondered how the mechanics actually work. I've seen a few of the other design where the concentric rings of LEDs are at different 'tilt out' angles so the beam spread is done simply by turning some off, but it's the mechanical ones I'm interested in.
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All the LED units with zoom that I've come across (GLP units) work by moving the front 'lens' about 2-3cm away from the LED's using two or three linear actuators. Although I'm guessing this would cause some serious issues if one if the actuators failed… would be interesting to see what would happen really.
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The budget RGBAW 36x15W led movers I have move the front lens ring away from the pcb, with a single worm drive in the centre. This can cause major problems as they came with a frost perspex front to "merge" the light back together. If you take the frost away, you get about a 30% increase in brightness, but you also get at certain zoom points, rings of different colours, similar to the dark focus ring you get with Selecon Acclaim fresnels as you move through the zoom range. Only noticeable to the discerning watcher or if someone points it out to you.


These colour rings do not affect the outdoor jazz shows I do, however I will eventually get around to buying LED zoom lens kits similar to Khatod moving lens.


My theory for the reason for the colour rings is that the LED emitters are on the circular pcb with a wide beam output. As the lens ring moves away to zoom in, the output of LED emitters passes out though adjacent lens and a spectrum shift occurs due to the angle that the light passes through adjacent lens, as these circles come and go as the zoom angle changes.


I watch for the rings and move the zoom slightly to avoid the effect. Most of my jazz shows are done on the fly so I need the ability to highlight solos and refocus after setting up during the afternoon.

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Useful info so thanks folks.


My usual supplier for audio products offered me 4, plus flight cases as a sample one-off for a quite reasonable sum, so I've ordered them. I can't find anything exactly the same, as the DMX chart is 16ch, and quite different to others that look the same, so it's a bit of a punt in the dark - but could be quite useful if they do what they claim.

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  • 2 weeks later...

I've had a chance to do a little testing on the units they sent me, and I'm impressed enough to have ordered some more.


I'll take some proper photographs and add them a little later, but I now know enough to make proper buying decisions - and I've done enough research to determine there are at least 2 designs being sold at the moment. These appear to share a common base unit, but have different heads.


The ones I have have a rear metal finned casting to act as a heat sink. The other variety has a moulded rear cover, and any heat sinks are not visible.


Thanks to Don for some info on his, and we appear to share many common features, but have differences in others.


Good features.


The plastic finish to the handles and some other parts is that type found on the older Pearl River movers - with a slightly rubbery feel.

Locking Powercon (style, not brand) mains input connector - supplied with a 2 pin continental plug.

Excellent light output - very close to the Robes I had in the rig last week.

Pretty good price for the performance and the size.

Flightcases are rather good - two unit per case, central compartment for the odds and ends.


Not so good features.


Plastic casing cracked on one unit when delivered - I can actually see how it happened. The guide foam in the case is there to align the units when the head is dropped into the cavity, and because of the sharp angle on the casing, it's possible to drop the unit into the case, and have one of these guides lifting the unit slightly . As the foam is pretty dense, when the lid was closed, it forced the base unit against the edge of the foam, and the plastic cracked across the foam line - a perfect match! The supplier is posting me a couple of replacements.


Fan noise - the units, when not lit, are silent. As soon as the light comes up, a fan powers up to keep it cool. The fan is pretty loud, but seems to do a good job, and on full for an hour, the heatsink remained just warm. Once the light goes out, the fan powers down shortly afterwards.


The hanging bracket - with a single suspension hole attaches with M8 allen bolts, so a bit of a pain - some designs seem to use Omega catches, but this one is firmly a tape the allen key to the box job!


In and out are on 3 Pin XLR. One odd feature is the programming, where the up and down buttons actually do the opposite so when sitting on the ground, the printing of the display is the right way up, but the arrows go the wrong way, so selecting DMX, then enter brings up the usual number, but then the arrow up button goes down in numbers. When hanging, the labels are then upside down, but the arrows work the right way. If you invert the display then the direction is wrong again. Doesn't matter really, just odd.


The unit comes with the previously mentioned 'diffuser' that attaches with three screws to the lens plate that travels in and out to vary the zoom. With the diffuser on, the beam has a nice soft edge and is fairly even in field. With the diffuser removed the result is a fairly well defined circle - not quite what I expected, but the edge has a colour fringe of the complimentary colour. In addition, there is a strange shadow extending out from the circle of light - looking like a kind of spoked dark shape, like the front cog on a pedal cycle? I didn't find the diffuser dimmed the beam very much, so it went back on straight away.


One good feature is that full RGB produces a quite even and decent coloured white light - swapping this for the white LED produces a small colour change, a tiny shift to the blue end - but RGB and W all on produce a nice bright white field - very useable.


I'll edit this a bit later to show the pictures.

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I have recently purchased 8 led moving head wash direct from China. They are similar to the ones for sale on Ebay with two exceptions. The display is a touch screen, and each led has a diffused lens. LED complement is 36 x 10w rgbw, zoom range is approx 20 - 55 deg. Dimming is very smooth, even at the bottom of the range. Individual control of each colour is also smooth. It is possible to fade to black without a sudden blackout. Fans are acceptable in terms of noise. The only thing I found that was odd was the fitting of a Powercon output as the mains input. When this was pointed out to the supplier, they offered to have the units back to change them, or to supply the correct blue Powercons for me to fit. Having stripped one of the units down to see how well they were constructed, the Powercon change is an easy job. The units are very tidy inside. They are on a par ( no pun intended ) with Chinese kit exhibited at PLASA by various companies in the £800 - £1200 price range. Cost to me was below £400 per unit, inclusive of UPS priority delivery. Would I buy again ? I just ordered another 8.
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Here are the pictures showing the good and weird bits.


Taken in my studio, with the unit sitting on the floor - ceiling at 8ft.The images don't show the narrow beam very well - to my eye, the hot spot in the centre is MUCH brighter than the area around it, the camera overexposed the hotspot.

1. White, on wide - with diffuser

2. White on narrow - with diffuser

3. White on wide - without diffuser - notice blue and red fringing

4. White on narrow - without diffuser - blue and greeny fringing

5. Magenta - on wide without diffuser - blue and red fringing?

6. Cyan - from the front, without diffuser

7. Diffuser off, notice the extra rim of light with 'cog' like spokes

8. Close up of the LED modules

9. Side view with diffuser on

10 Side view without diffuser

11 LED modules from the front

12 Front panel with broken plastic moulding removed - no branding on the fixture at all


In some circumstances, I can imagine taking the diffusers off could be rather useful, but the odd cog wheel shadows are a bit odd?


I've bought them at a good price as I've death with this people before - I'm quite happy with the quality and performance.

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Last time I mentioned one of my Chinese suppliers, a few weeks later one of my top sellers on ebay did a full stop, and two people, who are not, as far as I'm aware contributing members here suddenly had the very same item, selling with a tiny margin, so for the moment - I'm a bit loath to say who - because I'm going to hopefully buy more and sell a few.
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What sort of money will you be asking for them Paul? We might be in the market for a few, maybe not for a couple months tho, new bass amps are at the top of the shopping list at the moment.


Do they have a sound to light function? Might be useful for some of the disco dry hires we do.

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